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Essay on Human Evolution

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100 Words Essay on Human Evolution

Introduction.

Human evolution is the lengthy process of change by which people originated from apelike ancestors. It’s a fascinating journey that took millions of years.

The Beginning

Our story begins in Africa about 6 million years ago. The first humans were primates, similar to apes.

Walking Upright

Around 4 million years ago, early humans started walking upright. This trait, called bipedalism, set us apart from other apes.

Use of Tools

About 2.6 million years ago, humans started using tools. This was a major step in our evolution.

Development of Language

Human evolution is a fascinating subject. It helps us understand where we come from and who we are.

250 Words Essay on Human Evolution

Introduction to human evolution.

Human evolution is an intriguing scientific concept that traces the progression of Homo sapiens from our early ancestors. It is a multidimensional process that has been shaped by natural selection, genetic drift, migration, and mutation over millions of years.

The Early Beginnings

The journey of human evolution began approximately 6 million years ago in Africa, with the emergence of the first hominins, our earliest ancestors. These hominins were distinguished from apes by their upright posture and bipedal locomotion.

The Genus Homo

Around 2 million years ago, the genus Homo appeared, characterized by a significant increase in brain size and the advent of tool use. Homo habilis, Homo erectus, and eventually Homo sapiens, our species, were part of this genus. Homo sapiens are unique in their capacity for complex language, abstract thought, and creativity.

The Role of Environment

Environmental changes played a critical role in human evolution. For instance, climate fluctuations led to the development of traits like bipedalism, which allowed early hominins to adapt to diverse habitats.

Modern Humans and Migration

The story of human evolution is a testament to our species’ adaptability and resilience. It underscores the dynamic interplay between biology and environment, shaping our past and influencing our future. As we continue to unravel the mysteries of our evolution, we gain profound insights into what it means to be human.

500 Words Essay on Human Evolution

Human evolution is a fascinating and complex process that has shaped us into the beings we are today. It is a multidisciplinary field of science that encompasses biology, anthropology, archaeology, and genetics. The process of evolution involves a series of natural changes that cause species to arise, adapt to the environment, and eventually become extinct.

The Origins of Homo Sapiens

Over time, evolutionary pressures such as environmental changes and competition for resources led to the emergence of new hominin species. Around two million years ago, the genus Homo, which includes modern humans, emerged. The Homo species had larger brains and made sophisticated tools.

The Advent of Homo Sapiens

Approximately 300,000 years ago, Homo sapiens, our own species, appeared. Early Homo sapiens had a combination of physical traits from earlier hominin species and new traits that we still possess today, such as a high forehead and a chin. They also exhibited advanced behaviors, such as creating complex tools and engaging in symbolic behavior like art and burial rituals.

Migration and Modern Evolution

The Homo sapiens began to migrate out of Africa around 70,000 years ago, gradually populating the entire globe. They adapted to a variety of environments and developed diverse cultures. This migration and adaptation are reflected in the genetic diversity we see in modern humans.

Modern human evolution continues today. Humans are still evolving, with natural selection acting on traits such as resistance to diseases and the ability to digest certain foods. Furthermore, our cultural and technological advancements are now a significant driver of our evolution.

The journey of human evolution is a testament to the resilience and adaptability of our species. It is a complex process that has shaped our physical traits, behaviors, and cultures. As we continue to evolve and adapt to our changing world, we carry with us the legacy of millions of years of evolution. Understanding our evolutionary history not only helps us appreciate our place in the natural world but also sheds light on our future as a species.

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Essay on Human Evolution

Essay Contents:

Essay on the Models of Human Evolution

Essay # 1. Introduction to Human Evolution:

Evolution as a process is composed of two parts:

1. An organism reproducing mechanism that provides variable organisms. Changes to the organism are largely random and effect future generations. They are made without regard to consequences to the organism.

2. A changing environment which screens organism changes. The environment provides stress on the variable organisms that selectively allows, through competition, certain changes to become dominant and certain others to be eliminated, without consideration for the future of the mechanism.

That same process provides mechanism (organism) disintegration if a strong screening environment is not present. Evolution is a two-way process which does not always work to the long term advantage of the organism and in fact often becomes quite deadly to a given species and thereby eradicates it.

The evolutionary process is bidirectional in its effect. It may, depending on the environment, either improve a given characteristic or decay it. Since the first step in the process is largely random and most organisms are quite complex, almost all of the variations are harmful.

A characteristic of a species advances if the environment is harsh, since most harmful variations to that characteristic will be eliminated through death and suffering at a rapid rate, leaving only the inconsequential and helpful changes in the lineage.

If the environment is benign with respect to the capability of the species then the harmful changes are not eliminated and the species will degenerate to a point of balance with the environment.

Human evolution is the part of biological evolution concerning the emergence of Homo sapiens as a distinct species from other hominans, great apes and placental mammals. It is the subject of a broad scientific inquiry that seeks to understand and describe how this change occurred.

Mammals developed from primitive mammal-like reptiles during the Triassic Period, some 200-245 million years ago. After the terminal Cretaceous extinction (65 million years ago) eliminated the dinosaurs, mammals as one of the surviving groups, underwent an adaptive radiation during the Tertiary Period.

The major orders of mammals developed at this time, including the Primates to which humans belong. Other primates include the tarsiers, lemurs, gibbons, monkeys, and apes. Although we have significant differences from other primates, we share an evolutionary history that includes traits such as opposable thumbs, stereoscopic vision, larger brains, and nails replacing claws.

Primates are relatively unspecialized mammals- they have no wings, still have all four limbs, cannot run very fast, have generally weak teeth, and lack armor or thick protective hides. However, the combination of primate adaptations that include larger brains, tool use, social structure, stereoscopic color vision, highly developed forelimbs and hands, versatile teeth, and upright posture, place them among the most advanced mammals.

Approximately 20 million years ago central and east Africa was densely forested. Climatic changes resulting from plate tectonic movements and episodes of global cooling about 15 million years ago caused a replacement of the forest by a drier-adapted savanna mixed with open areas of forest. During the course of hominid evolution, periodic climate changes would trigger bursts of evolution and/or extinction.

Primates have modifications to their ulna and radius (bones of the lower arm) allowing them to turn their hand without turning their elbow. Many primates can also swivel or turn their arms at the shoulder. These two adaptations offer advantages to life in the trees.

Primates have five digits on their forelimbs. They are able to grasp objects with their forelimbs in what is known as a prehensile movement. A second modification makes one of the digits opposable, allowing the tips of the fingers and thumb to touch.

Placement of the eyes on the front of the head increases depth perception, an advantageous trait in tree-dwelling primates. Changes in the location of rods and cones in the eye adapted primates for color vision as well as peripheral vision in dim light.

Upright posture allows a primate to view its surroundings as well as to use its hands for some other task. Hominids, the lineage leading to humans, had changes in the shape and size of their pelvis, femur, and knees that allowed bipedalism (walking on two legs). The change from quadruped to biped happened in stages, culminating in humans, who can walk or run on two legs.

Several trends of primate evolution are evident in the teeth and jaw. First, change in the geometry of the jaw reduced the snout into a flat face. Second, changes in tooth arrangement and numbers increased the efficiency of those teeth for grinding food. Third, about 1.5 million years ago our diet changed from fruits and vegetables to include meat.

Essay # 2. Origin of Apes and Hominids:

The fossil record indicates primates evolved about approximately 30 million years ago in Africa. One branch of primates evolved into the Old and New World Monkeys, the other into the hominoids (the line of descent common to both apes and man).

Fossil hominoids occur in Africa during the Miocene epoch of the Tertiary period. They gave rise to an array of species in response to major climate fluxes in their habitats. However, the nature of those habitats leads to an obscuration of the line that leads to humans (the hominids).

Until a few years ago, the ramapiths were thought to have given rise to the hominids. We now consider ramapiths ancestral to the orangutang. The hominid line arose from some as-yet-unknown ancestor. Lacking fossil evidence, biochemical and DNA evidence suggests a split of the hominid from hominoid line about 6 to 8 million years ago.

Australopithecus afarensis, the first of the human-like hominids we know of, first appeared about 3.6-4 million years ago. This species had a combination of human (bipedalism) and apelike features (short legs and relatively long arms). The arm bones were curved like chimps, but the elbows were more human-like. Scientists speculate that A. afarensis spent some time climbing trees, as well as on the ground.

Australopithecus ramidus is an older species, about 4.4 million years, and is generally considered more anatomically primitive than A. afarensis. The relationship between the two species remains to be solved.

History of Man:

I. Ardipithicus ramidus- 5 to 4 million years ago

II. Australopithecus anamensis- 4.2 to 3.9 million years ago

III. Australopithecus afarensis- 4 to 2.7 million years ago

IV. Australopithecus africanus- 3 to 2 million years ago

V. Australopithecus robustus- 2.2 to 1.6 million years ago

VI. Homo habilis- 2.2 to 1.6 million years ago

VII. Homo erectus- 2.0 to 0.4 million years ago

VIII. Homo sapiens archaic- 400 to 200 thousand years ago

IX. Homo sapiens neandertalensis- 200 to 30 thousand years ago

X. Homo sapiens sapiens- 200 thousand years ago to present.

The role of A. afarensis as the stem from which the other hominids arose is in some dispute. About 2 million years ago, after a long million year period of little change, as many as six hominid species evolved in response to climate changes associated with the beginning of the Ice Age.

Two groups developed- the australopithecines, generally smaller brained and not users of tools; and the line that led to genus Homo, larger brained and makers and users of tools. The australopithecines died out 1 million years ago; Homo, despite their best efforts (atomic weapons, pollution) is still here!

With an incomplete fossil record, australopithecines, at least the smaller form, A. africanus, was thought ancestral to Homo. Recent discoveries however have caused a reevaluation of that hypothesis. One pattern is sure, human traits evolved at different rates and at different times, in a mosaic- some features (skeletal, dietary) establishing themselves quickly, others developing later (tool making, language, use of fire).

A cluster of species developed about 2-2.5 million years ago in Africa. Homo had a larger brain and a differently shaped skull and teeth than the australopithecines. About 1.8 million years ago, early Homo gave rise to Homo erectus, the species thought to have been ancestral to our own.

Soon after its origin (1.8 million but probably older than 2 million years ago) in Africa, Homo erectus appears to have migrated out of Africa and into Europe and Asia. Homo erectus differed from early species of Homo in having a larger brain size, flatter face, and prominent brow ridges. Homo erectus is similar to modern humans in size, but has some differences in the shape of the skull, a receding chin, brow ridges, and differences in teeth.

Homo erectus was the first hominid to:

1. Provide evidence the social and cultural aspects of human evolution.

2. Leave Africa (living in Africa, Europe, and Asia).

3. Use fire.

4. Have social structures for food gathering.

5. Utilize permanent settlements.

6. Provide a prolonged period of growth and maturation after birth Between 100,000 and 500,000 years ago, the world population of an estimated 1 million Homo erectus disappeared, replaced by a new species, Homo sapiens. How, when and where this new species arose and how it replaced its predecessor remain in doubt. Answering those questions has become a multidisciplinary task.

Two hypotheses differ on how and where Homo sapiens originated:

1. The Out-of-Africa Hypothesis proposes that some H. erectus remained in Africa and continued to evolve into H. sapiens, and left Africa about 100,000-200,000 years ago. From a single source, H. sapiens replaced all populations of H. erectus.

Human populations today are thus all descended from a single speciation event in Africa and should display a high degree of genetic similarity. Support for this hypothesis comes from DNA studies of mitochondria- since African populations display the greatest diversity of mitochondrial DNA, modern humans have been in Africa longer than they have been elsewhere. Calculations suggest all modern humans are descended from a population of African H. sapiens numbering as few as 10,000.

2. The Regional Continuity Hypothesis suggests that regional populations of H. erectus evolved into H. sapiens through interbreeding between the various populations. Evidence from the fossil record and genetic studies supports this idea.

Scientists can often use the same “evidence” to support contrasting hypotheses depending on which evidence (fossils or molecular clock/ DNA studies) one gives more weight to. The accuracy of the molecular clock, so key to the out-of-Africa hypothesis, has recently been questioned.

Recent studies on the Y-chromosome seem to weaken the regional continuity hypothesis by indicating a single point-of-origin for our species some 270,000 years ago. Continued study will no doubt reveal new evidence and undoubtedly new hypotheses will arise. It is a task for all of us to weigh the evidence critically and reach a supportable conclusion, whether we are scientists or not.

Essay # 3. H istory of the Primates:

Before Homo:

The evolutionary history of the primates can be traced back for some 85 million years, as one of the oldest of all surviving placental mammal groups. Most paleontologists consider that primates share a common ancestor with the bats, another extremely ancient lineage, and that this ancestor probably lived during the late Cretaceous, together with the last dinosaurs. The oldest known primates come from North America, but they were widespread in Eurasia and Africa as well, during the tropical conditions of the Paleocene and Eocene.

With the beginning of modern climates, marked by the formation of the first Antarctic ice in the early Oligocene around 40 million years ago, primates went extinct everywhere but Africa and southern Asia. One such primate from this time was Notharctus.

Fossil evidence found in Germany 20 years ago was determined to be about 16.5 million years old, some 1.5 million years older than similar species from East Africa. It suggests that the primate lineage of the great apes first appeared in Eurasia and not Africa.

The discoveries suggest that the early ancestors of the hominids (the family of great apes and humans) migrated to Eurasia from Africa about 17 million years ago, just before these two continents were cut off from each other by an expansion of the Mediterranean Sea. These primates flourished in Eurasia and that their lineage leading to the African apes and humans —Dryopithecus—migrated south from Europe or Western Asia into Africa.

The surviving tropical population, which is seen most completely in the upper Eocene and lowermost Oligocene fossil beds of the Fayum depression southwest of Cairo, gave rise to all living primates—lemurs of Madagascar, lorises of Southeast Asia, galagos or “bush babies” of Africa, and the anthropoids; platyrrhines or New World monkeys, and catarrhines or Old World monkeys and the great apes and humans.

The earliest known catarrhine is Kamoyapithecus from uppermost Oligocene at Eragaleit in the northern Kenya rift valley, dated to 24 mya (millions of years before present). Its ancestry is generally thought to be close to such genera as Aegyptopithecus, Propliopithecus, and Parapithecus from the Fayum, at around 35 mya.

There are no fossils from the intervening 11 million years. No near ancestor to South American platyrrhines, whose fossil record begins at around 30 mya, can be identified among the North African fossil species, and possibly lies in other forms that lived in West Africa that were caught up in the still-mysterious transatlantic sweepstakes that sent primates, rodents, boa constrictors, and cichlid fishes from Africa to South America sometime in the Oligocene.

In the early Miocene, after 22 mya, many kinds of arboreally adapted primitive catarrhines from East Africa suggest a long history of prior diversification. Because the fossils at 20 mya include fragments attributed to Victoriapithecus, the earliest cercopithecoid, the other forms are (by default) grouped as hominoids, without clear evidence as to which are closest to living apes and humans.

Among the presently recognised genera in this group, which ranges up to 13 mya, we find Proconsul, Rangwapithecus, Dendropithecus, Limnopithecus, Nacholapithecus, Equatorius, Nyanzapithecus, Afropithecus, Heliopithecus, and Kenyapithecus, all from East Africa.

The presence of other generalised non-cercopithecids of middle Miocene age from sites far distant—Otavipithecus from cave deposits in Namibia, and Pierolapithecus and Dryopithecus from France, Spain and Austria—is evidence of a wide diversity of forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the early and middle Miocene.

The youngest of the Miocene hominoids, Oreopithecus, is from 9 mya coal beds in Italy.

Molecular evidence indicates that the lineage of gibbons (family Hylobatidae) became distinct between 18 and 12 Ma, and that of orangutans (subfamily Ponginae) at about 12 Ma; we have no fossils that clearly document the ancestry of gibbons, which may have originated in a so far unknown South East Asian hominid population, but fossil proto-orangutans may be represented by Ramapithecus from India and Griphopithecus from Turkey, dated to around 10 Ma.

It has been suggested that species close to last common ancestors of gorillas, chimpanzees and humans may be represented by Nakalipithecus fossils found in Kenya and Ouranopithecus found in Greece.

Molecular evidence suggests that between 8 and 4 mya, first the gorillas, and then the chimpanzee (genus Pan) split off from the line leading to the humans; human DNA is 98.4 percent identical to the DNA of chimpanzees. We have no fossil record, however, of either group of African great apes, possibly because bones do not fossilize in rain forest environments.

Hominines, however, seem to have been one of the mammal groups (as well as antelopes, hyenas, dogs, pigs, elephants, and horses) that adapted to the open grasslands as soon as this biome appeared, due to increasingly seasonal climates, about 8 mya, and their fossils are relatively well known.

The earliest are Sahelanthropus tchadensis (7- 6 mya) and Orrorin tugenensis (6 mya), followed by:

1. Ardipithecus (5.5-4.4 mya), with species Ar. kadabba and Ar. Ramidus.

2. Australopithecus (4-2 mya), with species Au. anamensis, Au. afarensis, Au. africanus, Au. bahrelghazali, and Au. Garhi.

3. Kenyanthropus (3-2.7 mya), with species Kenyanthropus platyops.

4. Paranthropus (3-1.2 mya), with species P. aethiopicus, P. boisei, and P. robustus.

5. Homo (2 mya-present), with species Homo habilis, Homo rudolfensis, Homo ergaster, Homo georgicus, Homo antecessor, Homo cepranensis, Homo erectus, Homo heidelbergensis, Homo rhodesiensis, Homo sapiens neanderthalensis, Homo sapiens idaltu, Archaic Homo sapiens, Homo floresiensis.

Essay # 4. Genus of Homo:

The word homo is Latin for “human”, chosen originally by Carolus Linnaeus in his classification system. It is often translated as “man”, although this can lead to confusion, given that the English word “man” can be generic like homo, but can also specifically refer to males. Latin for “man” in the gender-specific sense is vir (pronounced weer), cognate with “virile” and “werewolf”. The word “human” is from humanus, the adjectival form of homo.

In modern taxonomy, Homo sapiens are the only extant species of its genus, Homo. Likewise, the ongoing study of the origins of Homo sapiens often demonstrates that there were other Homo species, all of which are now extinct. While some of these other species might have been ancestors of H. sapiens, many were likely our “cousins”, having speciated away from our ancestral line.

There is not yet a consensus as to which of these groups should count as separate species and which as subspecies of another species. In some cases this is due to the paucity of fossils, in other cases it is due to the slight differences used to classify species in the Homo genus. The Sahara pump theory provides an explanation of the early variation in the genus Homo.

i. Homo Habilis:

H. habilis lived from about 2.4 to 1.4 million years ago (mya). H. habilis, the first species of the genus Homo, evolved in South and East Africa in the late Pliocene or early Pleistocene, 2.5-2 mya, when it diverged from the Australopithecines.

H. habilis had smaller molars and larger brains than the Australopithecines, and made tools from stone and perhaps animal bones. One of the first known hominids, it was nicknamed ‘handy man’ by its discoverer, Louis Leakey. Some scientists have proposed moving this species out of Homo and into Australopithecus.

ii. Homo Rudolfensis and Homo Georgicus:

These are proposed species names for fossils from about 1.9 -1.6 mya, the relation of which with H. habilis is not yet clear. H. rudolfensis refers to a single, incomplete skull from Kenya. Scientists have suggested that this was just another habilis, but this has not been confirmed.

H. georgicus, from Georgia, may be an intermediate form between H. habilis and H. erectus, or a sub-species of H. erectus.

iii. Homo Ergaster and Homo Erectus:

The first fossils of Homo erectus were discovered by Dutch physician Eugene Dubois in 1891 on the Indonesian island of Java. He originally gave the material the name Pithecanthropus erectus based on its morphology that he considered to be intermediate between that of humans and apes.

H. erectus lived from about 1.8 mya to 70,000 years ago. Often the early phase, from 1.8 to 1.25 mya, is considered to be a separate species, H. ergaster, or it is seen as a subspecies of erectus, Homo erectus ergaster.

In the Early Pleistocene, 1.5-1 mya, in Africa, Asia, and Europe, presumably, Homo habilis evolved larger brains and made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, H. erectus. In addition H. erectus was the first human ancestor to walk truly upright.

This was made possible by the evolution of locking knees and a different location of the foramen magnum (the hole in the skull where the spine enters). They may have used fire to cook their meat.

A famous example of Homo erectus is Peking Man; others were found in Asia (notably in Indonesia), Africa, and Europe. Many paleoanthropologists are now using the term Homo ergaster for the non-Asian forms of this group, and reserving H. erectus only for those fossils found in the Asian region and meeting certain skeletal and dental requirements which differ slightly from ergaster.

iv. Homo Cepranensis and Homo Antecessor:

These are proposed as species that may be intermediate between H. erectus and H. heidelbergensis.

H. cepranensis refers to a single skull cap from Italy, estimated to be about 800,000 years old.

H. antecessor is known from fossils from Spain and England that are 800,000-500,000 years old.

v. Homo Heidelbergensis:

H. heidelbergensis (Heidelberg Man) lived from about 800,000 to about 300,000 years ago. Also proposed as Homo sapiens heidelbergensis or Homo sapiens paleohungaricus.

vi. Homo Neanderthalensis:

H. neanderthalensis lived from about 250,000 to as recent as 30,000 years ago. Also proposed as Homo sapiens neanderthalensis- there is ongoing debate over whether the ‘Neanderthal Man’ was a separate species, Homo neanderthalensis, or a subspecies of H. sapiens.

While the debate remains unsettled, evidence from mitochondrial DNA and Y-chromosomal DNA sequencing indicates that little or no gene flow occurred between H. neanderthalensis and H. sapiens, and, therefore, the two were separate species.

vii. Homo Rhodesiensis, and the Gawis Cranium:

H. rhodesiensis, estimated to be 300,000-125,000 years old, most current experts believe Rhodesian Man to be within the group of Homo heidelbergensis though other designations such as Archaic Homo sapiens and Homo sapiens rhodesiensis have also been proposed.

In February 2006 a fossil, the Gawis cranium, was found which might possibly be a species intermediate between H. erectus and H. sapiens or one of many evolutionary dead ends. The skull from Gawis, Ethiopia, is believed to be 500,000-250,000 years old.

Only summary details are known, and no peer reviewed studies have been released by the finding team. Gawis man’s facial features suggest its being either an intermediate species or an example of a “Bodo man” female.

viii. Homo Sapiens:

H. sapiens (“sapiens” means wise or intelligent) has lived from about 250,000 years ago to the present. Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in cranial expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens.

The direct evidence suggests that there was a migration of H. erectus out of Africa, then a further speciation of H. sapiens from H. erectus in Africa (there is little evidence that this speciation occurred elsewhere). Then a subsequent migration within and out of Africa eventually replaced the earlier dispersed H. erectus.

This migration and origin theory is usually referred to as the single- origin theory. However, the current evidence does not preclude multiregional speciation, either. This is a hotly debated area in paleoanthropology.

Current research has established that human beings are genetically highly homogenous, that is the DNA of individuals is more alike than usual for most species, which may have resulted from their relatively recent evolution or the Toba catastrophe. Distinctive genetic characteristics have arisen, however, primarily as the result of small groups of people moving into new environmental circumstances.

These adapted traits are a very small component of the Homo sapiens genome and include such outward “racial” characteristics as skin color and nose form in addition to internal characteristics such as the ability to breathe more efficiently in high altitudes.

H. sapiens idaltu, from Ethiopia, lived from about 160,000 years ago (proposed subspecies). It is the oldest known anatomically modern human.

ix. Homo Floresiensis :

H. floresiensis, which lived about 100,000-12,000 years ago has been nicknamed hobbit for its small size, possibly a result of insular dwarfism. H. floresiensis is intriguing both for its size and its age, being a concrete example of a recent species of the genus Homo that exhibits derived traits not shared with modern humans.

In other words, H. floresiensis share a common ancestor with modern humans, but split from the modern human lineage and followed a distinct evolutionary path. The main find was a skeleton believed to be a woman of about 30 years of age. Found in 2003 it has been dated to approximately 18,000 years old. Her brain size was only 380 cm 3 (which can be considered small even for a chimpanzee). She was only 1 meter in height.

However, there is an ongoing debate over whether H. floresiensis is indeed a separate species. Some scientists presently believe that H. floresiensis was a modern H. sapiens suffering from pathological dwarfism.

Use of Tools:

Using tools has been interpreted as a sign of intelligence, and it has been theorized that tool use may have stimulated certain aspects of human evolution—most notably the continued expansion of the human brain. Paleontology has yet to explain the expansion of this organ over millions of years despite being extremely demanding in terms of energy consumption.

The brain of a modern human consumes about 20 Watts (400 kilocalories per day), which is one fifth of the energy consumption of a human body. Increased tool use would allow for hunting and consuming meat, which is more energy-rich than plants. Researchers have suggested that early hominids were thus under evolutionary pressure to increase their capacity to create and use tools.

Precisely when early humans started to use tools is difficult to determine, because the more primitive these tools are (for example, sharp-edged stones) the more difficult it is to decide whether they are natural objects or human artifacts.

Stone Tools:

Stone tools are first attested around 2.6 million years ago, when H. habilis in Eastern Africa used so-called pebble tools, choppers made out of round pebbles that had been split by simple strikes.

This marks the beginning of the Paleolithic, or Old Stone Age; its end is taken to be the end of the last Ice Age, around 10,000 years ago. The Paleolithic is subdivided into the Lower Paleolithic (Early Stone Age, ending around 350,000-300,000 years ago), the Middle Paleolithic (Middle Stone Age, until 50,000-30,000 years ago), and the Upper Paleolithic.

The period from 700,000-300,000 years ago is also known as the Acheulean, when H. ergaster (or erectus) made large stone hand-axes out of flint and quartzite, at first quite rough (Early Acheulian), later “retouched” by additional, more subtle strikes at the sides of the flakes.

After 350,000 BP (Before Present) the more refined so-called Levallois technique was developed. It consisted of a series of consecutive strikes, by which scrapers, slicers (“racloirs”), needles, and flattened needles were made. Finally, after about 50,000 BP, ever more refined and specialised flint tools were made by the Neanderthals and the immigrant Cro-Magnons (knives, blades, skimmers). In this period they also started to make tools out of bone.

Essay # 5. Evolution of Neanderthals :

Archaic H. sapiens lived from 500,000 to 30,000 years ago and combined features of H. sapiens with those of H. erectus. The Neanderthals, considered in this group, lived in Europe and western Asia between 100,000 and 30,000 years ago before their disappearance.

Neanderthals were larger-brained than modern humans, had a sloping forehead, prominent brow ridges and a receding chin. They had a very prominent nose and ranged in height from 5 foot 2 inches (average female) to 5 foot 6 inches (average male).

Despite their image as brutish simpletons, Neanderthals were the first humans to bury their dead with artifacts, indicating abstract thought, perhaps a belief in an after-life. They lived in free-standing settlements, as well as caves. Neanderthal tools were more sophisticated than H. erectus’ tools, employing handles to gain extra leverage.

Did Neanderthals evolve gradually into modern humans, or were they replaced by modern forms originating from a single population? The answer to that depends on the answer to the question of the origin of H. sapiens from H. erectus. The out-of-Africa hypothesis suggests Neanderthals were a separate species (H. neandertalensis) replaced as modern humans (H. sapiens) spread from Africa. The regional continuity hypothesis suggests Neanderthals were a subspecies (H. sapiens neandertalensis) that evolved into modern humans (H. sapiens sapiens).

Agriculture and Migrations :

Since the evolution of H. erectus, migrations have been a fact of human existence, helping to spread genetic diversity as well as technological innovation. The most recent innovations have not been physical, but rather cultural.

The Neolithic transition, about 10,000 years ago, involved the change from hunter-gatherer societies to agricultural ones based on cultivation of plants and domesticated animals. Evidence suggests this began in the Middle East and spread outward via migrations. Genetic studies suggest agriculture spread by the migration of farmers into hunter-gatherer societies. This would produce a genetic blurring as the farmers interbred with the indigenous peoples, a pattern supported by genetics.

Most anthropologists agree that the New World was populated by a series of three migrations over the temporary land connection between Asia and North America. The Immigrants spread southward, eventually reaching Tierra del Fuego in the southernmost part of South America.

Anthropological and linguistic studies find three groups of peoples:

1. The Amerinds, who spread across North and South America.

2. The Na-Denes, who occupied the northwestern region of North America.

3. The Eskaleuts, Eskimo and Aleut peoples who live in the far north.

Mitochondrial DNA studies find four distinct groups descended from peoples of Siberia. Amerind mtDNA suggests two waves of migration (one perhaps as old as 21-42 thousand years ago). The genetic model confirms the accepted ideas about human migration into the Americas and suggests a possible fourth wave.

Essay # 6. Models of Human Evolution:

Today, all humans are classified as belonging to the species Homo sapiens sapiens. However, this is not the first species of hominids- the first species of genus Homo, Homo habilis evolved in East Africa at least 2 million years ago, and members of this species populated different parts of Africa in a relatively short time.

Homo erectus evolved more than 1.8 million years ago, and by 1.5 million years ago had spread throughout the Old World. Virtually all physical anthropologists agree that Homo sapiens evolved out of Homo erectus.

Anthropologists have been divided as to whether Homo sapiens evolved as one interconnected species from H. erectus (called the Multiregional Model, or the Regional Continuity Model), or evolved only in East Africa, and then migrated out of Africa and replaced H. erectus populations throughout the Old World (called the Out of Africa Model or the Complete Replacement Model).

Anthropologists continue to debate both possibilities, and the evidence is technically ambiguous as to which model is correct, although most anthropologists currently favor the Out of Africa model.

Multiregional Model :

Advocates of the Multiregional model, primarily Milford Wolpoff and his followers, have argued that the simultaneous evolution of H. sapiens in different parts of Europe and Asia would have been possible if there was a degree of gene flow between archaic populations.

Similarities of morphological features between archaic European and Chinese populations and modern H. sapiens from the same regions, Wolpoff argues, support a regional continuity only possible within the Multiregional model. Wolpoff and others further argue that this model is consistent with clonal patterns of phenotypic variation.

Out of Africa Model :

According to the Out of Africa Model, developed by Christopher Stringer and Peter Andrews, modern H. sapiens evolved in Africa 200,000 years ago. Homo sapiens began migrating from Africa between 70,000 – 50,000 years ago and would eventually replace existing hominid species in Europe and Asia.

The Out of Africa Model has gained support by recent research using mitochondrial DNA (mtDNA). After analysing genealogy trees constructed using 133 types of mtDNA, they concluded that all were descended from a woman from Africa, dubbed Mitochondrial Eve.

A variation on this model involves the Southern dispersal theory, which has gained support in recent years from genetic, linguistic and archaeological evidence. In this theory, there was a coastal dispersal of modern humans from the Horn of Africa around 70,000 years ago. This group helped to populate Southeast Asia and Oceania, explaining the discovery of early human sites in these areas much earlier than those in the Levant.

A second wave of humans dispersed across the Sinai peninsula into Asia, resulting in the bulk of human population for Eurasia. This second group possessed a more sophisticated tool technology and was less dependent on coastal food sources than the original group. Much of the evidence for the first group’s expansion would have been destroyed by the rising sea levels at the end of the Holocene era.

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Introduction to Human Evolution

Human evolution

Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.

One of the earliest defining human traits, bipedalism -- the ability to walk on two legs -- evolved over 4 million years ago. Other important human characteristics -- such as a large and complex brain, the ability to make and use tools, and the capacity for language -- developed more recently. Many advanced traits -- including complex symbolic expression, art, and elaborate cultural diversity -- emerged mainly during the past 100,000 years.

Humans are primates. Physical and genetic similarities show that the modern human species, Homo sapiens , has a very close relationship to another group of primate species, the apes. Humans and the great apes (large apes) of Africa -- chimpanzees (including bonobos, or so-called “pygmy chimpanzees”) and gorillas -- share a common ancestor that lived between 8 and 6 million years ago. Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa.

Most scientists currently recognize some 15 to 20 different species of early humans. Scientists do not all agree, however, about how these species are related or which ones simply died out. Many early human species -- certainly the majority of them – left no living descendants. Scientists also debate over how to identify and classify particular species of early humans, and about what factors influenced the evolution and extinction of each species.

Early humans first migrated out of Africa into Asia probably between 2 million and 1.8 million years ago. They entered Europe somewhat later, between 1.5 million and 1 million years. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years and to the Americas within the past 30,000 years or so. The beginnings of agriculture and the rise of the first civilizations occurred within the past 12,000 years.

Paleoanthropology

Paleoanthropology is the scientific study of human evolution. Paleoanthropology is a subfield of anthropology, the study of human culture, society, and biology. The field involves an understanding of the similarities and differences between humans and other species in their genes, body form, physiology, and behavior. Paleoanthropologists search for the roots of human physical traits and behavior. They seek to discover how evolution has shaped the potentials, tendencies, and limitations of all people. For many people, paleoanthropology is an exciting scientific field because it investigates the origin, over millions of years, of the universal and defining traits of our species. However, some people find the concept of human evolution troubling because it can seem not to fit with religious and other traditional beliefs about how people, other living things, and the world came to be. Nevertheless, many people have come to reconcile their beliefs with the scientific evidence.

Early human fossils and archeological remains offer the most important clues about this ancient past. These remains include bones, tools and any other evidence (such as footprints, evidence of hearths, or butchery marks on animal bones) left by earlier people. Usually, the remains were buried and preserved naturally. They are then found either on the surface (exposed by rain, rivers, and wind erosion) or by digging in the ground. By studying fossilized bones, scientists learn about the physical appearance of earlier humans and how it changed. Bone size, shape, and markings left by muscles tell us how those predecessors moved around, held tools, and how the size of their brains changed over a long time. Archeological evidence refers to the things earlier people made and the places where scientists find them. By studying this type of evidence, archeologists can understand how early humans made and used tools and lived in their environments.

The process of evolution

The process of evolution involves a series of natural changes that cause species (populations of different organisms) to arise, adapt to the environment, and become extinct. All species or organisms have originated through the process of biological evolution. In animals that reproduce sexually, including humans, the term species refers to a group whose adult members regularly interbreed, resulting in fertile offspring -- that is, offspring themselves capable of reproducing. Scientists classify each species with a unique, two-part scientific name. In this system, modern humans are classified as Homo sapiens .

Evolution occurs when there is change in the genetic material -- the chemical molecule, DNA -- which is inherited from the parents, and especially in the proportions of different genes in a population. Genes represent the segments of DNA that provide the chemical code for producing proteins. Information contained in the DNA can change by a process known as mutation. The way particular genes are expressed – that is, how they influence the body or behavior of an organism -- can also change. Genes affect how the body and behavior of an organism develop during its life, and this is why genetically inherited characteristics can influence the likelihood of an organism’s survival and reproduction.

Evolution does not change any single individual. Instead, it changes the inherited means of growth and development that typify a population (a group of individuals of the same species living in a particular habitat). Parents pass adaptive genetic changes to their offspring, and ultimately these changes become common throughout a population. As a result, the offspring inherit those genetic characteristics that enhance their chances of survival and ability to give birth, which may work well until the environment changes. Over time, genetic change can alter a species' overall way of life, such as what it eats, how it grows, and where it can live. Human evolution took place as new genetic variations in early ancestor populations favored new abilities to adapt to environmental change and so altered the human way of life.

Dr. Rick Potts provides a video short introduction to some of the evidence for human evolution, in the form of fossils and artifacts.

Climate Effects on Human Evolution
Survival of the Adaptable
Human Evolution Timeline Interactive
2011 Olorgesailie Dispatches
2004 Olorgesailie Dispatches
1999 Olorgesailie Dispatches
Olorgesailie Drilling Project
Kanam, Kenya
Kanjera, Kenya
Ol Pejeta, Kenya
Olorgesailie, Kenya
Evolution of Human Innovation
Adventures in the Rift Valley: Interactive
'Hobbits' on Flores, Indonesia
Earliest Humans in China
Bose, China
Anthropocene: The Age of Humans
Fossil Forensics: Interactive
What's Hot in Human Origins?
Instructions
Carnivore Dentition
Ungulate Dentition
Primate Behavior
Footprints from Koobi Fora, Kenya
Laetoli Footprint Trails
Footprints from Engare Sero, Tanzania
Hammerstone from Majuangou, China
Handaxe and Tektites from Bose, China
Handaxe from Europe
Handaxe from India
Oldowan Tools from Lokalalei, Kenya
Olduvai Chopper
Stone Tools from Majuangou, China
Middle Stone Age Tools
Burin from Laugerie Haute & Basse, Dordogne, France
La Madeleine, Dordogne, France
Butchered Animal Bones from Gona, Ethiopia
Katanda Bone Harpoon Point
Oldest Wooden Spear
Punctured Horse Shoulder Blade
Stone Sickle Blades
Projectile Point
Oldest Pottery
Pottery Fragment
Fire-Altered Stone Tools
Terra Amata Shelter
Qafzeh: Oldest Intentional Burial
Assyrian Cylinder Seal
Blombos Ocher Plaque
Ishango Bone
Bone and Ivory Needles
Carved Ivory Running Lion
Female torso in ivory
Ivory Horse Figurine
Ivory Horse Sculpture
Lady of Brassempouy
Lion-Man Figurine
Willendorf Venus
Ancient Shell Beads
Carved Bone Disc
Cro-Magnon Shell Bead Necklace
Oldest Known Shell Beads
Ancient Flute
Ancient Pigments
Apollo 11 Plaque
Carved antler baton with horses
Geometric incised bone rectangle
Tata Plaque
Mystery Skull Interactive
Shanidar 3 - Neanderthal Skeleton
One Species, Living Worldwide
Human Skin Color Variation
Ancient DNA and Neanderthals
Human Family Tree
Swartkrans, South Africa
Shanidar, Iraq
Walking Upright
Tools & Food
Social Life
Language & Symbols
Humans Change the World
Nuts and bolts classification: Arbitrary or not? (Grades 6-8)
Comparison of Human and Chimp Chromosomes (Grades 9-12)
Hominid Cranial Comparison: The "Skulls" Lab (Grades 9-12)
Investigating Common Descent: Formulating Explanations and Models (Grades 9-12)
Fossil and Migration Patterns in Early Hominids (Grades 9-12)
For College Students
Why do we get goose bumps?
Chickens, chimpanzees, and you - what do they have in common?
Grandparents are unique to humans
How strong are we?
Humans are handy!
Humans: the running ape
Our big hungry brain!
Our eyes say it!
The early human tool kit
The short-haired human!
The “Nutcracker”
What can lice tell us about human evolution?
What does gut got to do with it?
Why do paleoanthropologists love Lucy?
Why do we have wisdom teeth?
Human Origins Glossary
Teaching Evolution through Human Examples
Frequently Asked Questions
Recommended Books
Exhibit Floorplan Interactive
Print Floorplan PDF
Reconstructions of Early Humans
Chesterfield County Public Library
Orange County Library
Andover Public Library
Ephrata Public Library
Oelwein Public Library
Cedar City Public Library
Milpitas Library
Spokane County Library
Cottage Grove Public Library
Pueblo City-County Library
Springfield-Greene County Library
Peoria Public Library
Orion Township Public Library
Skokie Public Library
Wyckoff Free Public Library
Tompkins County Public Library
Otis Library
Fletcher Free Library
Bangor Public Library
Human Origins Do it Yourself Exhibit
Exhibit Field Trip Guide
Acknowledgments
Human Origins Program Team
Connie Bertka
Betty Holley
Nancy Howell
Lee Meadows
Jamie L. Jensen
David Orenstein
Michael Tenneson
Leonisa Ardizzone
David Haberman
Fred Edwords (Emeritus)
Elliot Dorff (Emeritus)
Francisca Cho (Emeritus)
Peter F. Ryan (Emeritus)
Mustansir Mir (Emeritus)
Randy Isaac (Emeritus)
Mary Evelyn Tucker (Emeritus)
Wentzel van Huyssteen (Emeritus)
Joe Watkins (Emeritus)
Tom Weinandy (Emeritus)
Members Thoughts on Science, Religion & Human Origins (video)
Science, Religion, Evolution and Creationism: Primer
The Evolution of Religious Belief: Seeking Deep Evolutionary Roots
Laboring for Science, Laboring for Souls: Obstacles and Approaches to Teaching and Learning Evolution in the Southeastern United States
Public Event : Religious Audiences and the Topic of Evolution: Lessons from the Classroom (video)
Evolution and the Anthropocene: Science, Religion, and the Human Future
Imagining the Human Future: Ethics for the Anthropocene
Human Evolution and Religion: Questions and Conversations from the Hall of Human Origins
I Came from Where? Approaching the Science of Human Origins from Religious Perspectives
Religious Perspectives on the Science of Human Origins
Submit Your Response to "What Does It Mean To Be Human?"
Volunteer Opportunities
Submit Question
"Shaping Humanity: How Science, Art, and Imagination Help Us Understand Our Origins" (book by John Gurche)
What Does It Mean To Be Human? (book by Richard Potts and Chris Sloan)
Bronze Statues
Reconstructed Faces

Introductory essay

Written by the educator who created What Makes Us Human?, a brief look at the key facts, tough questions and big ideas in his field. Begin this TED Study with a fascinating read that gives context and clarity to the material.

As a biological anthropologist, I never liked drawing sharp distinctions between human and non-human. Such boundaries make little evolutionary sense, as they ignore or grossly underestimate what we humans have in common with our ancestors and other primates. What's more, it's impossible to make sharp distinctions between human and non-human in the paleoanthropological record. Even with a time machine, we couldn't go back to identify one generation of humans and say that the previous generation contained none: one's biological parents, by definition, must be in the same species as their offspring. This notion of continuity is inherent to most evolutionary perspectives and it's reflected in the similarities (homologies) shared among very different species. As a result, I've always been more interested in what makes us similar to, not different from, non-humans.

Evolutionary research has clearly revealed that we share great biological continuity with others in the animal kingdom. Yet humans are truly unique in ways that have not only shaped our own evolution, but have altered the entire planet. Despite great continuity and similarity with our fellow primates, our biocultural evolution has produced significant, profound discontinuities in how we interact with each other and in our environment, where no precedent exists in other animals. Although we share similar underlying evolved traits with other species, we also display uses of those traits that are so novel and extraordinary that they often make us forget about our commonalities. Preparing a twig to fish for termites may seem comparable to preparing a stone to produce a sharp flake—but landing on the moon and being able to return to tell the story is truly out of this non-human world.

Humans are the sole hominin species in existence today. Thus, it's easier than it would have been in the ancient past to distinguish ourselves from our closest living relatives in the animal kingdom. Primatologists such as Jane Goodall and Frans de Waal, however, continue to clarify why the lines dividing human from non-human aren't as distinct as we might think. Goodall's classic observations of chimpanzee behaviors like tool use, warfare and even cannibalism demolished once-cherished views of what separates us from other primates. de Waal has done exceptional work illustrating some continuity in reciprocity and fairness, and in empathy and compassion, with other species. With evolution, it seems, we are always standing on the shoulders of others, our common ancestors.

Primatology—the study of living primates—is only one of several approaches that biological anthropologists use to understand what makes us human. Two others, paleoanthropology (which studies human origins through the fossil record) and molecular anthropology (which studies human origins through genetic analysis), also yield some surprising insights about our hominin relatives. For example, Zeresenay Alemsegad's painstaking field work and analysis of Selam, a 3.3 million-year old fossil of a 3-year-old australopithecine infant from Ethiopia, exemplifies how paleoanthropologists can blur boundaries between living humans and apes.

Selam, if alive today, would not be confused with a three-year-old human—but neither would we mistake her for a living ape. Selam's chimpanzee-like hyoid bone suggests a more ape-like form of vocal communication, rather than human language capability. Overall, she would look chimp-like in many respects—until she walked past you on two feet. In addition, based on Selam's brain development, Alemseged theorizes that Selam and her contemporaries experienced a human-like extended childhood with a complex social organization.

Fast-forward to the time when Neanderthals lived, about 130,000 – 30,000 years ago, and most paleoanthropologists would agree that language capacity among the Neanderthals was far more human-like than ape-like; in the Neanderthal fossil record, hyoids and other possible evidence of language can be found. Moreover, paleogeneticist Svante Pääbo's groundbreaking research in molecular anthropology strongly suggests that Neanderthals interbred with modern humans. Paabo's work informs our genetic understanding of relationships to ancient hominins in ways that one could hardly imagine not long ago—by extracting and comparing DNA from fossils comprised largely of rock in the shape of bones and teeth—and emphasizes the great biological continuity we see, not only within our own species, but with other hominins sometimes classified as different species.

Though genetics has made truly astounding and vital contributions toward biological anthropology by this work, it's important to acknowledge the equally pivotal role paleoanthropology continues to play in its tandem effort to flesh out humanity's roots. Paleoanthropologists like Alemsegad draw on every available source of information to both physically reconstruct hominin bodies and, perhaps more importantly, develop our understanding of how they may have lived, communicated, sustained themselves, and interacted with their environment and with each other. The work of Pääbo and others in his field offers powerful affirmations of paleoanthropological studies that have long investigated the contributions of Neanderthals and other hominins to the lineage of modern humans. Importantly, without paleoanthropology, the continued discovery and recovery of fossil specimens to later undergo genetic analysis would be greatly diminished.

Molecular anthropology and paleoanthropology, though often at odds with each other in the past regarding modern human evolution, now seem to be working together to chip away at theories that portray Neanderthals as inferior offshoots of humanity. Molecular anthropologists and paleoanthropologists also concur that that human evolution did not occur in ladder-like form, with one species leading to the next. Instead, the fossil evidence clearly reveals an evolutionary bush, with numerous hominin species existing at the same time and interacting through migration, some leading to modern humans and others going extinct.

Molecular anthropologist Spencer Wells uses DNA analysis to understand how our biological diversity correlates with ancient migration patterns from Africa into other continents. The study of our genetic evolution reveals that as humans migrated from Africa to all continents of the globe, they developed biological and cultural adaptations that allowed for survival in a variety of new environments. One example is skin color. Biological anthropologist Nina Jablonski uses satellite data to investigate the evolution of skin color, an aspect of human biological variation carrying tremendous social consequences. Jablonski underscores the importance of trying to understand skin color as a single trait affected by natural selection with its own evolutionary history and pressures, not as a tool to grouping humans into artificial races.

For Pääbo, Wells, Jablonski and others, technology affords the chance to investigate our origins in exciting new ways, adding pieces into the human puzzle at a record pace. At the same time, our technologies may well be changing who we are as a species and propelling us into an era of "neo-evolution."

Increasingly over time, human adaptations have been less related to predators, resources, or natural disasters, and more related to environmental and social pressures produced by other humans. Indeed, biological anthropologists have no choice but to consider the cultural components related to human evolutionary changes over time. Hominins have been constructing their own niches for a very long time, and when we make significant changes (such as agricultural subsistence), we must adapt to those changes. Classic examples of this include increases in sickle-cell anemia in new malarial environments, and greater lactose tolerance in regions with a long history of dairy farming.

Today we can, in some ways, evolve ourselves. We can enact biological change through genetic engineering, which operates at an astonishing pace in comparison to natural selection. Medical ethicist Harvey Fineberg calls this "neo-evolution". Fineberg goes beyond asking who we are as a species, to ask who we want to become and what genes we want our offspring to inherit. Depending on one's point of view, the future he envisions is both tantalizing and frightening: to some, it shows the promise of science to eradicate genetic abnormalities, while for others it raises the specter of eugenics. It's also worth remembering that while we may have the potential to influence certain genetic predispositions, changes in genotypes do not guarantee the desired results. Environmental and social pressures like pollution, nutrition or discrimination can trigger "epigenetic" changes which can turn genes on or off, or make them less or more active. This is important to factor in as we consider possible medical benefits from efforts in self-directed evolution. We must also ask: In an era of human-engineered, rapid-rate neo-evolution, who decides what the new human blueprints should be?

Technology figures in our evolutionary future in other ways as well. According to anthropologist Amber Case, many of our modern technologies are changing us into cyborgs: our smart phones, tablets and other tools are "exogenous components" that afford us astonishing and unsettling capabilities. They allow us to travel instantly through time and space and to create second, "digital selves" that represent our "analog selves" and interact with others in virtual environments. This has psychological implications for our analog selves that worry Case: a loss of mental reflection, the "ambient intimacy" of knowing that we can connect to anyone we want to at any time, and the "panic architecture" of managing endless information across multiple devices in virtual and real-world environments.

Despite her concerns, Case believes that our technological future is essentially positive. She suggests that at a fundamental level, much of this technology is focused on the basic concerns all humans share: who am I, where and how do I fit in, what do others think of me, who can I trust, who should I fear? Indeed, I would argue that we've evolved to be obsessed with what other humans are thinking—to be mind-readers in a sense—in a way that most would agree is uniquely human. For even though a baboon can assess those baboons it fears and those it can dominate, it cannot say something to a second baboon about a third baboon in order to trick that baboon into telling a fourth baboon to gang up on a fifth baboon. I think Facebook is a brilliant example of tapping into our evolved human psychology. We can have friends we've never met and let them know who we think we are—while we hope they like us and we try to assess what they're actually thinking and if they can be trusted. It's as if technology has provided an online supply of an addictive drug for a social mind evolved to crave that specific stimulant!

Yet our heightened concern for fairness in reciprocal relationships, in combination with our elevated sense of empathy and compassion, have led to something far greater than online chats: humanism itself. As Jane Goodall notes, chimps and baboons cannot rally together to save themselves from extinction; instead, they must rely on what she references as the "indomitable human spirit" to lessen harm done to the planet and all the living things that share it. As Goodall and other TED speakers in this course ask: will we use our highly evolved capabilities to secure a better future for ourselves and other species?

I hope those reading this essay, watching the TED Talks, and further exploring evolutionary perspectives on what makes us human, will view the continuities and discontinuities of our species as cause for celebration and less discrimination. Our social dependency and our prosocial need to identify ourselves, our friends, and our foes make us human. As a species, we clearly have major relationship problems, ranging from personal to global scales. Yet whenever we expand our levels of compassion and understanding, whenever we increase our feelings of empathy across cultural and even species boundaries, we benefit individually and as a species.

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Zeresenay Alemseged

The search for humanity's roots, relevant talks.

We are all cyborgs now

Frans de Waal

Moral behavior in animals.

Harvey Fineberg

Are we ready for neo-evolution.

Jane Goodall

What separates us from chimpanzees.

Nina Jablonski

Skin color is an illusion.

Spencer Wells

A family tree for humanity.

Svante Pääbo

Dna clues to our inner neanderthal.

Human Evolution

Six million years of human evolution.

Paleoanthropology is the scientific study of human evolution which investigates the origin of the universal and defining traits of our species. The field involves an understanding of the similarities and differences between humans and other species in their genes, body form, physiology, and behavior. Paleoanthropologists search for the roots of human physical traits and behavior. They seek to discover how evolution has shaped the potentials, tendencies, and limitations of all people.

What Can Human Fossils Tell Us?

Early human fossils and archeological remains offer the most important clues about this ancient past. These remains include bones, tools and any other evidence (such as footprints, evidence of hearths , or butchery marks on animal bones) left by earlier people. Usually, the remains were buried and preserved naturally. They are then found either on the surface (exposed by rain, rivers, and wind erosion) or by digging in the ground. By studying fossilized bones, scientists learn about the physical appearance of earlier humans and how it changed. Bone size, shape, and markings left by muscles tell us how those predecessors moved around, held tools, and how the size of their brains changed over a long time.

Archeological evidence refers to the things earlier people made and the places where scientists find them. By studying this type of evidence, archeologists can understand how early humans made and used tools and lived in their environments.

Humans and Our Evolutionary Relatives

Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa. Early humans first migrated out of Africa into Asia probably between 2 million and 1.8 million years ago. They entered Europe somewhat later, between 1.5 million and 1 million years. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years and to the Americas within the past 15,000 years or so.

Most scientists currently recognize some 15 to 20 different species of early humans. Scientists do not all agree, however, about how these species are related or which ones simply died out. Many early human species – certainly the majority of them – left no living descendants. Scientists also debate over how to identify and classify particular species of early humans, and about what factors influenced the evolution and extinction of each species.

Human Characteristics

One of the earliest defining human traits, bipedalism – the ability to walk on two legs – evolved over 4 million years ago. Other important human characteristics – such as a large and complex brain, the ability to make and use tools, and the capacity for language – developed more recently. Many advanced traits -- including complex symbolic expression, art , and elaborate cultural diversity – emerged mainly during the past 100,000 years. The beginnings of agriculture and the rise of the first civilizations occurred within the past 12,000 years.

Smithsonian Research Into Human Evolution

The Smithsonian’s Human Origins Program explores the universal human story at its broadest time scale. Smithsonian anthropologists research many aspects of human evolution around the globe, investigating fundamental questions about our evolutionary past, including the roots of human adaptability.

For example, Paleoanthropologist Dr. Rick Potts – who directs the Human Origins Program – co-directs ongoing research projects in southern and western Kenya and southern and northern China that compare evidence of early human behavior and environments from eastern Africa to eastern Asia. Rick’s work helps us understand the environmental changes that occurred during the times that many of the fundamental characteristics that make us human - such as making tools and large brains – evolved, and that our ancestors were often able to persist through dramatic climate changes. Rick describes his work in the video Survivors of a Changing Environment .

Dr. Briana Pobiner is a Prehistoric Archaeologist whose research centers on the evolution of human diet (with a focus on meat-eating), but has included topics as diverse as cannibalism in the Cook Islands and chimpanzee carnivory. Her research has helped us understand that at the onset of human carnivory over 2.5 million years ago some of the meat our ancestors ate was scavenged from large carnivores, but by 1.5 million years ago they were getting access to some of the prime, juicy parts of large animal carcasses. She uses techniques similar to modern day forensics for her detective work on early human diets.

Paleoanthropologist Dr. Matt Tocheri conducts research into the evolutionary history and functional morphology of the human and great ape family, the Hominidae. His work on the wrist of Homo floresiensis , the so-called “hobbits” of human evolution discovered in Indonesia, received considerable attention worldwide after it was published in 2007 in the journal Science. He now co-directs research at Liang Bua on the island of Flores in Indonesia, the site where Homo floresiensis was first discovered.

Geologist Dr. Kay Behrensmeyer has been a long-time collaborator with Rick Potts’ human evolution research at the site of Olorgesailie in southern Kenya. Kay’s role with the research there is to help understand the environments of the sites at which evidence for early humans – in the form of stone tools as well as fossils of the early humans themselves – have been found, by looking at the sediments of the geological layers in which the artifacts and fossils have been excavated.

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Darwin’s Theory of Human Evolution Essay

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Darwin’s Evidence to Theory of Human Evolution

Question of the relationship between religion and science, darwin voice the concern for realism and concrete facts, works cited.

Darwin presents several arguments to support his proposition that man originated from some form of lowly species. To begin with, he asserts that the embryonic development between man and other animals is similar. In other words, the growth cycle of man and other lowly animals or organism demonstrates a lot of distinct similarities that have never been disputed.

For example, conception is the first process of bringing forth life in both man and other animals. Second, the stages of embryonic development are similar in both cases because the embryo takes a particular period before it can transform into a new form of life or creation. Darwin notes that the conception period might be the only difference between man and other living organisms.

There is also a close similarity between man and other animals in terms of geographic distribution. Both of them have been spatially distributed in such a way that they can depend and co-exist with each other. The spatial distribution of man and other animals is also largely dependent on the availability of resources required for sustainable growth.

The evolutionist also stresses the point that even though man has been classified in form other races, it is similar to the case of other animals. Perhaps, the only difference is the wording pattern because animals are grouped into species while human beings are categorized in various races. Also, man retains the same rudiments as other lower animals because he descended from a lowly organized form. Darwin has used these pieces of evidence to support his theory of evolution.

Although Darwin seems to refute the religious claim on the origin of man, it is apparent that both religion and science share a common hypothesis that man has a distinct origin. Nonetheless, the evidence provided above by Charles Darwin contrast the religious belief that man was created by the Supreme Being called God. Science does not recognize the presence of God as referred by Christians and other religions.

Also, it is prudent to underscore the fact that science relies on evidence that can be proven while religion revolves around various abstract belief systems with no evidence at all. This explains why the evidence provided by science on the evolution of man cannot be accommodated by religion. Therefore, religion and science will continue to offer opposite thoughts and perspectives due to the parallels that have been drawn between evidence and belief systems (Lualdi 182).

Darwin readily mentions that several critics will judge his theory of evolution on the origin of the species without giving key attention to the concrete facts and realism presented by the same theory. He appears to be quite aware that the theory may elicit a long debate afterward. Indeed, the evolution theory was not received warmly from all quarters because Darwin was sharply criticized by religious adherents and other scientists.

The evolution theorist emphasizes that he has offered adequate scientific knowledge on the origin of man because he is aware that the theory is bound to be the core subject of discussion for a long time. Darwin is also concerned that hopes and fears can hardly reveal the pertinent facts on the origin of man. He adds that truth based on scientific evidence should be the main guideline on all arguments presented from different viewpoints.

Lualdi, K. Sources of the Making of the West: Peoples and Cultures. Volume II: Since 1500 . Boston: Bedford/St. Martin’s, 2012. Print.

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Home — Essay Samples — Science — Human Evolution

Essays on Human Evolution

Human evolution stands as a captivating subject that spans millions of years, detailing the biological and anthropological journey from our earliest ancestors to modern Homo sapiens. Essays on human evolution provide a fascinating opportunity to explore the theories, discoveries, and debates that have shaped our understanding of this complex process. We want to guide students through the intricacies of writing compelling essays on human evolution, leveraging the rich collection of essay samples available on GradesFixer.

Exploring the Milestones of Human Evolution

The journey of human evolution is marked by significant milestones that highlight the adaptability and diversity of human species over time. Essays may delve into various aspects of this journey, including:

Origins of Bipedalism: Investigating the shift to bipedal locomotion and its implications for human ancestors' lifestyle, habitat, and survival strategies.
Development of Tool Use: Examining the evidence for early tool use and its role in the development of human cognition, social structures, and technological advancement.
Evolution of Language and Communication: Exploring theories on the origins and evolution of language , and how communication has shaped human societies and cultures.
Genetic and Fossil Evidence: Analyzing the fossil record and genetic data to trace the evolutionary lineage of humans and understand the relationship between modern humans and extinct hominin species.

Benefits of Using Human Evolution Essay Samples

Utilizing essay samples on human evolution can offer several advantages to students:

Framework for Essay Structure: Samples provide a blueprint for effectively organizing an essay, from introducing the topic to presenting arguments and concluding insights.
Diverse Perspectives on Evolutionary Theories: By reviewing different essays, students can engage with a variety of perspectives and theories, enriching their own analysis and understanding.
Incorporation of Scientific Evidence: Samples demonstrate how to integrate scientific evidence, including fossil records and genetic data, to support claims and arguments.
Inspiration for Critical Analysis: Engaging with various essays encourages students to critically analyze the evidence and theories of human evolution, fostering a deeper understanding of the subject.

Tips for Writing an Engaging Human Evolution Essay

Crafting a compelling essay on human evolution involves several key strategies:

Select a Specific Focus: Given the broad scope of human evolution, narrowing down to a particular topic or question can provide depth and clarity to your essay.
Incorporate Interdisciplinary Insights: Human evolution is a multidisciplinary subject. Including insights from anthropology, genetics, and paleontology can offer a comprehensive view.
Address Controversies and Debates: Exploring the debates and controversies within the field of human evolution, such as the exact lineage of Homo sapiens, can add a dynamic and engaging element to your essay.
Reflect on the Implications for Humanity: Consider the broader implications of human evolution studies for understanding human nature, society, and the future of our species.

Writing a human evolution essay is an invitation to journey through the annals of time, uncovering the story of our origins and the evolutionary milestones that define us as a species. By drawing on essay samples for structure, inspiration, and evidence, students can craft essays that not only meet academic standards but also contribute to the ongoing exploration of human evolution. This subject offers a unique lens through which we can examine ourselves, providing insights into our past, present, and potential future.

Human evolution is a testament to the resilience, adaptability, and ingenuity of our species. Through their essays, students have the opportunity to engage with this rich history, adding their voices to the fascinating dialogue about what it means to be human.

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Ch. 1 The Study of History and the Rise of Civilization

The evolution of humans, learning objective.

To understand the process and timeline of human evolution
Humans began to evolve about seven million years ago, and progressed through four stages of evolution. Research shows that the first modern humans appeared 200,000 years ago.
Neanderthals were a separate species from humans. Although they had larger brain capacity and interbred with humans, they eventually died out.
A number of theories examine the relationship between environmental conditions and human evolution.
The main human adaptations have included bipedalism, larger brain size, and reduced sexual dimorphism.

aridity hypothesis

The theory that the savannah was expanding due to increasingly arid conditions, which then drove hominin adaptation.

turnover pulse hypothesis

The theory that extinctions due to environmental conditions hurt specialist species more than generalist ones, leading to greater evolution among specialists.

Red Queen hypothesis

The theory that species must constantly evolve in order to compete with co-evolving animals around them.

encephalization

An evolutionary increase in the complexity and/or size of the brain.

sexual dimorphism

Differences in size or appearance between the sexes of an animal species.

social brain hypothesis

The theory that improving cognitive capabilities would allow hominins to influence local groups and control resources.

Toba catastrophe theory

The theory that there was a near-extinction event for early humans about 70,000 years ago.

savannah hypothesis

The theory that hominins were forced out of the trees they lived in and onto the expanding savannah; as they did so, they began walking upright on two feet.

A primate of the family Hominidae that includes humans and their fossil ancestors.

Describing an animal that uses only two legs for walking.

Human evolution began with primates. Primate development diverged from other mammals about 85 million years ago. Various divergences among apes, gibbons, orangutans occurred during this period, with Homini (including early humans and chimpanzees) separating from Gorillini (gorillas) about 8 millions years ago. Humans and chimps then separated about 7.5 million years ago.

Skeletal structure of humans and other primates. A comparison of the skeletal structures of gibbons, humans, chimpanzees, gorillas and orangutans.

Generally, it is believed that hominids first evolved in Africa and then migrated to other areas. There were four main stages of human evolution. The first, between four and seven million years ago, consisted of the proto hominins Sahelanthropus , Orrorin and Ardipithecus. These humans may have been bipedal, meaning they walked upright on two legs. The second stage, around four million years ago, was marked by the appearance of Australopithecus, and the third, around 2.7 million years ago, featured Paranthropus.

The fourth stage features the genus Homo, which existed between 1.8 and 2.5 million years ago. Homo habilis , which used stone tools and had a brain about the size of a chimpanzee, was an early hominin in this period. Coordinating fine hand movements needed for tool use may have led to increasing brain capacity. This was followed by Homo erectus and Homo ergaster , who had double the brain size and may have been the first to control fire and use more complex tools. Homo heidelbergensis appeared about 800,000 years ago, and modern humans, Homo sapiens , about 200,000 years ago. Humans acquired symbolic culture and language about 50,000 years ago.

Comparison of skull features among early humans.A comparison of Homo habilis, Homo erectus, Homo floresiensis and Homo naledi skull features.

Neanderthals

A separate species, Homo neanderthalensi s, had a common ancestor with humans about 660,000 years ago, and engaged in interbreeding with Homo sapiens about 45,000 to 80,000 years ago. Although their brains were larger, Neanderthals had fewer social and technological innovations than humans, and they eventually died out.

Theories of Early Human Evolution

The savannah hypothesis states that hominins were forced out of the trees they lived in and onto the expanding savannah; as they did so, they began walking upright on two feet. This idea was expanded in the aridity hypothesis, which posited that the savannah was expanding due to increasingly arid conditions resulting in hominin adaptation. Thus, during periods of intense aridification, hominins also were pushed to evolve and adapt.

The turnover pulse hypothesis states that extinctions due to environmental conditions hurt specialist species more than generalist ones. While generalist species spread out when environmental conditions change, specialist species become more specialized and have a greater rate of evolution. The Red Queen hypothesis states that species must constantly evolve in order to compete with co-evolving animals around them. The social brain hypothesis states that improving cognitive capabilities would allow hominins to influence local groups and control resources. The Toba catastrophe theory states that there was a near-extinction event for early humans about 70,000 years ago.

Human Adaptations

Bipedalism, or walking upright, is one of the main human evolutionary adaptations. Advantages to be found in bipedalism include the freedom of the hands for labor and less physically taxing movement. Walking upright better allows for long distance travel and hunting, for a wider field of vision, a reduction of the amount of skin exposed to the sun, and overall thrives in a savannah environment. Bipedalism resulted in skeletal changes to the legs, knee and ankle joints, spinal vertebrae, toes, and arms. Most significantly, the pelvis became shorter and rounded, with a smaller birth canal, making birth more difficult for humans than other primates. In turn, this resulted in shorter gestation (as babies need to be born before their heads become too large), and more helpless infants who are not fully developed before birth.

Larger brain size, also called encephalization, began in early humans with Homo habilis and continued through the Neanderthal line (capacity of 1,200 – 1,900 cm3). The ability of the human brain to continue to grow after birth meant that social learning and language were possible. It is possible that a focus on eating meat, and cooking, allowed for brain growth. Modern humans have a brain volume of 1250 cm3.

Humans have reduced sexual dimorphism, or differences between males and females, and hidden estrus, which means the female is fertile year-round and shows no special sign of fertility. Human sexes still have some differences between them, with males being slightly larger and having more body hair and less body fat. These changes may be related to pair bonding for long-term raising of offspring.

Other adaptations include lessening of body hair, a chin, a descended larynx, and an emphasis on vision instead of smell.

Human Evolution

A video showing evolution from early animals to modern humans.

Boundless World History. Authored by : Boundless. Located at : https://www.boundless.com/world-history/textbooks/boundless-world-history-textbook/ . License : CC BY-SA: Attribution-ShareAlike

At the Smithsonian | December 27, 2022

Fourteen Discoveries Made About Human Evolution in 2022

Smithsonian paleoanthropologists reveal the year’s most riveting findings about our close relatives and ancestors

A team led by Laurits Skov and Benjamin Peter from the Max Planck Institute for Evolutionary Anthropology sequenced nuclear, mitochondrial and Y-chromosome DNA of 13 Neanderthal individuals. From these sequences, they determined that two of the Neanderthals represent a father-daughter pair and that another two are cousins.

Ryan McRae and Briana Pobiner

With many projects around the world proceeding despite the Covid-19 pandemic, researchers across a variety of fields made multiple exciting breakthroughs on human origins, gaining more insight into topics ranging from food and drink to interspecies cooperation.

Telling us more about our food, our health, our close relatives and ancestors, and even our animal friends, these 14 new discoveries scientists made this year shed more light on what it means to be human.

Meat, fire and beer: origins of modern food staples

Hominins fishing and cooking on the shores of an ancient lake

For decades, one of the hallmarks of human evolution has been the presumed shift from a predominantly plant-based diet to one that included significant amounts of meat and animal tissue. Scientists surmised that since meat is generally more nutrient-dense, more meat-eating could have allowed our ancestors, beginning with the emergence of Homo erectus around 2 million years ago, to evolve the large and energetically demanding brains that we associate with our own species.

But the question remained: Did meat consumption actually increase after this time, inferred by stone tool butchery marks on fossilized bones, or is there just more fossil material overall from that period—making it more likely to find these butchery marks?

In January, W. Andrew Barr from George Washington University and colleagues examined all the fossil evidence for butchery in eastern Africa from 1.2 million years ago and older. They concluded that the evidence for increased carnivory in our ancestors is merely an effect of increased sampling of the archaeological record at certain time intervals starting around two million years ago, meaning that there is no strong relationship between eating more meat and the evolution of larger brains in our ancestors.

Well, if it wasn’t meat eating that enabled big brains to evolve, maybe it was cooking?

Cooking makes food easier to digest, allowing for the extraction of more nutrients from food while expending less energy. The earliest evidence for human control of fire dates back to at least one million years ago, but the earliest evidence for using fire to cook food is much more recent.

In November, a team led by Irit Zohar from Tel Aviv University made breakthrough discoveries from the Israeli site Gesher Benot Ya’aqov that pushed this date back to around 600,000 years ago with new evidence for hominins cooking fish. Teeth of a species of carp were subjected to temperatures required to cook fish, but not as hot as temperatures directly inside a fire would be. This indicates the fish were placed above or next to the fire for cooking rather than being discarded in the fire or burned accidentally.

Of course, what good is barbecue without a tasty beverage to wash it down? In December 2021, a team led by Jiajing Wang from Dartmouth University uncovered the oldest known beer production in the world in Egypt. Made of fermented grains, the production of beer is closely linked to the emergence and spread of agricultural societies.

Dating to 5,800 years ago, hundreds of years before Egypt’s first pharaoh, this beer was thick like a porridge rather than watery and probably used for both daily consumption and ritual purposes. Yum?

Animal friends and animal food: origins of domestication and cooperation

Whether for work, companionship or food, domesticated animals make modern human existence possible. But do human impacts on animal communities in a broader sense date back far earlier than evidence for domestication?

In July, a team led by Danielle Fraser from the Canadian Museum of Nature quantified species evenness in North America over the past 20,000 years and found that there were two periods when the diversity of animal communities notably decreased. The first, around 10,000 years ago, was associated with the North American megafauna extinction. The other occurred around 2,000 years ago during a period in which agriculture spread rapidly and population sizes boomed.

This study demonstrates that humans can affect, and have affected, animal communities in indirect ways in addition to hunting and domestication.

When it comes to domesticated animals, perhaps none captures the imagination and our emotions like humankind’s best friend—the dog.

Dogs are also currently the earliest known domesticated animal on earth. A June study led by Anders Bergström and Pontus Skoglund of the Francis Crick Institute looked at genomes of ancient wolves, from whom our species domesticated the modern dog, to try to determine where and when the connection between humans and dogs began.

They found that ancient wolf populations in North America, Europe and Siberia were interconnected with each other in the past rather than being separate populations as they are today, and that all dogs included in the study are most closely related to wolves from eastern Eurasia rather than from western Eurasia.

However, ancient wolves in southwest Eurasia made significant contributions to the genome of dogs originating from the Near East and Africa—either indicating a separate domestication process or, more likely, interbreeding with that additional wolf population early in the process (just as early members of our own species interbred with Neanderthals when we first left Africa).

While this study points strongly to eastern Eurasia as the geographic source of modern dogs, none of the ancient wolf populations studied were the direct ancestor of modern dogs, meaning that the true dog ancestor (or ancestors) is yet to be found.

In addition to companionship, humans also domesticated animals for food and to assist with work. A study in June led by Joris Peters from Ludwig Maximilian University Munich and Greger Larson from the University of Oxford traced the origin of chicken domestication to around 1650 B.C.E. in Thailand, corresponding to the spread of grains (specifically rice and millet). Chickens then appear to follow the grains as they spread around the world as a food source.

Clearly, modern humans owe a lot to our animal friends, and new finds continue to shed light on where, when and how these interspecies interactions first emerged.

New fossils shed light on old ancestors: discoveries from our earliest and most recent evolutionary history

As in previous years, 2022 revealed more fossil finds tied to our human lineage’s earliest history.

One of the first possible hominins, Sahelanthropus tchadensis , dates to around six to seven million years ago and was found in Chad in Central Africa. This species was previously known only by cranial remains and a partial femur, but in August a team led by Guillaume Daver and Franck Guy from the University of Poitiers reinterpreted the femur (upper leg bone) and described two ulnae (forearm bones). These ulnae share many affinities with our ape relatives and suggest that while Sahelanthropus may have been bipedal on the ground, its arms were still well adapted to climbing and clambering in trees.

On the more recent side of prehistory: New fossils of the enigmatic Denisovans , known mostly from their DNA, are starting to tell us more about where they lived and what they looked like. Following up on a Denisovan mandible found in Tibet in 2019, a Denisovan molar was recently discovered in Laos. Dating to between 130,000 to 160,000 years old, this is the first Denisovan fossil found in a geographic area where scientists now know their DNA wound up. Many populations of modern Southeast Asian, Papuan and Filipino people have some Denisovan DNA in them— up to five percent in one Indigenous Filipino group . We’re looking forward to more new finds of Denisovan fossils to tell us more about who they were and what they looked like, as well as when and how they interacted with our own species.

Speaking of species interactions, new finds in February from a cave in southeast France are complicating the story of human-Neanderthal co-occupation of Europe. A team led by Ludovic Slimak from the University of Toulouse unearthed evidence of hominin occupation at a site called Grotte Mandrin in France: First Neanderthals were there, then modern humans, then Neanderthals again before modern humans became the only hominin in Europe.

From both lithic and fossil evidence, this modern human occupation dates to older than 50,000 years ago, almost 10,000 years older than the previous record for modern humans in this region. This evidence tells us that not only did Neanderthals and modern humans live in the same area for a long span of time (potentially implying that our presence in Europe did not drive Neanderthals to extinction), but also that these two species occupied the same site alternately. This extended timespan of interaction could have implications for genetics as well, potentially adding another data point to the where and when of modern human-Neanderthal interbreeding .

Friends and family ties in modern apes and Neanderthals

Fourteen Discoveries Made About Human Evolution in 2022

While most studies of apes focus on groups of only one species at a time, some apes, like chimpanzees and gorillas, do overlap in multiple locations—providing an opportunity to observe the interactions between them. Often when two closely related species overlap in range, their actions are predominantly antagonistic or aggressive toward the other group.

But in the Nouabalé-Ndoki National Park in the Congo Republic, chimpanzees and gorillas have been observed being downright friendly with each other. From the two species foraging in the same tree, to their young playing with each other, to individuals forming lasting friendships, chimps and gorillas have generally gotten along over the 20-year period of study led by Crickette Sanz of Washington University in St. Louis, which was announced in October. This interspecies cooperation may offer a large advantage in deterring predators like leopards and in helping each other find valuable food sources.

While it is relatively straightforward to observe group dynamics in living apes, figuring out how now-extinct early human groups lived and interacted is much trickier, as population-level studies require multiple fossils from the same site at the same time period.

Between two cave sites in southern Siberia (the Chagyrskaya and Okladnikov caves), in October a team led by Laurits Skov and Benjamin Peter from the Max Planck Institute for Evolutionary Anthropology sequenced nuclear, mitochondrial and Y-chromosome DNA of 13 Neanderthal individuals. From these sequences, they determined that two of the Neanderthals represent a father-daughter pair and that another two are cousins.

Additionally, evidence points to one-third of the Neanderthals being part of the same tightly knit community living around 54,000 years ago. Such small-scale resolution is almost unheard of in paleoanthropology. Analysis of the Y-chromosome (passed on through males) and mitochondrial (passed on through females) DNA reveals that the individuals had significantly less diverse Y-chromosome DNA, indicating that Neanderthal females were the ones to relocate to different groups, diversifying the mitochondrial DNA gene pool—in much the same pattern as has been observed in living chimpanzees.

These findings give us new insights into Neanderthal social structure, and potentially even to how interbreeding with our own species may have occurred.

How disease shapes us, and how we evolved to treat it

Modern medicine is thought to have arisen at least by the time of agriculture and large-scale population centers, possibly as a result of their development. More people means more disease, and humans would have looked for new ways to treat diseases. But something as medically complex as limb amputations were only known to occur as far back as 7,000 years ago and were not commonly known until a few hundred years ago, long after the rise of agricultural societies.

However, a new finding out of Borneo in Indonesia pushes this date back to as much as 31,000 years ago. A team led by Tim Maloney from Griffith University in Australia suggests that this individual appears to have had their leg surgically amputated just above the ankle, and then proceeded to live for another six to nine years based on bone remodeling around the amputation site. This evidence implies that modern humans had complex medical knowledge, such as how to locate and sever blood vessels, nerves, muscle tissue and bone, both safely and effectively, long before the advent of agriculture.

Yet, medicinal knowledge is not relegated to our own species. While animals like elephants, bears and other apes have been known to ingest material for medicinal purposes, it was not until this year that a team led by Simone Pika from the University of Osnabrück observed apes using topical ointments for healing . After catching insects, the wild chimpanzees from the Rekambo community in Gabon then squished them between their lips, rubbed the insect in the wound and removed the insect afterward.

The truly groundbreaking part of the study, announced in February, is that the chimpanzees treated not only their own wounds but also other chimps’ wounds. This sort of caring behavior was assumed to be reserved for our own species, but it seems like caring for others in one’s community could have deeper roots in our evolutionary history.

Another new study out in July led by Pascal Gagneux and Ajit Varki of the University of California San Diego looked at the intersection of medicine and genetics to explore why modern humans have developed such a long post-reproductive lifespan.

The “ grandmother hypothesis ” posits that modern humans live well past sexual maturity in order to care for family members, specifically grandchildren. But when did this long lifespan evolve— and how? A specific gene that produces immune receptors (like specialized parts of immune system cells) called CD33 allows modern humans to prevent some side effects of aging, specifically protecting the brain from inflammation and dementia. The gene for these CD33 receptors is not present in Neanderthals or Denisovans, meaning that it could be one advantage our species had over them, but it also means we had to have acquired it on our own rather than inheriting the gene from a common ancestor. One hypothesis this study explored comes from reproductive health: the idea that we evolved these receptors to fight gonorrhea bacteria. The bacterium coats itself in sugars to mimic the human body, and our version of the CD33 receptors can effectively fight it—sparing our reproductive health. This potentially indicates that this adaptation to reproductive health could have been co-opted by the human body to allow for longer lifespans. In other words, we evolved the CD33 receptors to fight gonorrhea, and as a result our bodies could fight against dementia and allow us to become grandparents.

Most notable: a new 2022 Nobel Laureate

While important strides have been made in genetics and human evolution in the past year, the most notable achievement must go to a new Nobel laureate Svante Pääbo . Born in Sweden in 1955, Pääbo has long been a leader in the field of ancient DNA, especially when it comes to humans and our closest relatives.

In 2010, Pääbo’s team deciphered the Neanderthal genome, unlocking a whole new realm of anthropological insight. Pääbo has also been at the forefront of new discoveries in anthropology, including identifying the Denisovans and understanding the genetic relationships among Denisovans, Neanderthals and our own species, as well as identifying the first early human Neanderthal-Denisovan hybrid . For these reasons and more, Pääbo was awarded the 2022 Nobel Prize in Physiology or Medicine, a fantastic way to round out 2022. Congratulations!

A version of this article was originally published on the PLOS SciComm blog.

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Ryan McRae | READ MORE

Dr. Ryan McRae is a paleoanthropologist studying the hominin fossil record on a macroscopic scale. He currently works for the National Museum of Natural History’s Human Origins Program as a contractor focusing on research, education, and outreach, and is an adjunct assistant professor of anatomy at the George Washington University School of Medicine and Health Sciences.

Briana Pobiner | READ MORE

Briana Pobiner is a paleoanthropologist with the National Museum of Natural History’s Human Origins Program . She lead's the program's education and outreach efforts.

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Biology archive

Course: biology archive > unit 23.

Introduction to evolution and natural selection
Ape clarification
Natural selection and the owl butterfly
Darwin, evolution, & natural selection
Variation in a species
Natural selection and Darwin

Evidence for evolution

Key points:

Anatomy. Species may share similar physical features because the feature was present in a common ancestor ( homologous structures ).
Molecular biology. DNA and the genetic code reflect the shared ancestry of life. DNA comparisons can show how related species are.
Biogeography. The global distribution of organisms and the unique features of island species reflect evolution and geological change.
Fossils. Fossils document the existence of now-extinct past species that are related to present-day species.
Direct observation. We can directly observe small-scale evolution in organisms with short lifecycles (e.g., pesticide-resistant insects).

Introduction

Evolution happens on large and small scales.

Macroevolution , which refers to large-scale changes that occur over extended time periods, such as the formation of new species and groups.
Microevolution , which refers to small-scale changes that affect just one or a few genes and happen in populations over shorter timescales.

The evidence for evolution

Anatomy and embryology, homologous features, analogous features, determining relationships from similar features, molecular biology.

The same genetic material (DNA)
The same, or highly similar, genetic codes
The same basic process of gene expression (transcription and translation)
The same molecular building blocks, such as amino acids

Homologous genes

Biogeography, fossil record, direct observation of microevolution.

Before DDT was applied, a tiny fraction of mosquitos in the population would have had naturally occurring gene versions ( alleles ) that made them resistant to DDT. These versions would have appeared through random mutation , or changes in DNA sequence. Without DDT around, the resistant alleles would not have helped mosquitoes survive or reproduce (and might even have been harmful), so they would have remained rare.
When DDT spraying began, most of the mosquitos would have been killed by the pesticide. Which mosquitos would have survived? For the most part, only the rare individuals that happened to have DDT resistance alleles (and thus survived being sprayed with DDT). These surviving mosquitoes would have been able to reproduce and leave offspring.
Over generations, more and more DDT-resistant mosquitoes would have been born into the population. That's because resistant parents would have been consistently more likely to survive and reproduce than non-resistant parents, and would have passed their DDT resistance alleles (and thus, the capacity to survive DDT) on to their offspring. Eventually, the mosquito populations would have bounced back to high numbers, but would have been composed largely of DDT-resistant individuals.
Homologous structures provide evidence for common ancestry, while analogous structures show that similar selective pressures can produce similar adaptations (beneficial features).
Similarities and differences among biological molecules (e.g., in the DNA sequence of genes) can be used to determine species' relatedness.
Biogeographical patterns provide clues about how species are related to each other.
The fossil record, though incomplete, provides information about what species existed at particular times of Earth’s history.
Some populations, like those of microbes and some insects, evolve over relatively short time periods and can observed directly.

Attribution:

Works cited:.

Nothing in biology makes sense except in the light of evolution. (2016, April 6). Retrieved May 15, 2016 from Wikipedia: https://en.wikipedia.org/wiki/Nothing_in_Biology_Makes_Sense_Except_in_the_Light_of_Evolution .
Wilkin, D. and Akre, B. (2016, March 23). Comparative anatomy and embryology - Advanced. In CK-12 biology advanced concepts . Retrieved from http://www.ck12.org/book/CK-12-Biology-Advanced-Concepts/section/10.22/ .
Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., and Jackson, R. B. (2011). Anatomical and molecular homologies. In Campbell biology (10th ed., p. 474). San Francisco, CA: Pearson.
Chapman, B. R. and Bolen, E. G. (2015). Convergent evolution [Glossary entry]. In Ecology of North America (2nd ed., p. 311). West Sussex, UK: John Wiley & Sons.
Insulin. (2014, June 6). In UCSD signaling gateway . Retrieved from http://www.signaling-gateway.org/molecule/query?afcsid=A004315&type=orthologs&adv=latest .
Wilkin, D. and Akre, B. (2016, March 23). Evolution and the fossil record - Advanced. In CK-12 biology advanced concepts . Retrieved from http://www.ck12.org/book/CK-12-Biology-Advanced-Concepts/section/10.21/ .
Reece, J. B., Taylor, M. R., Simon, E. J., and Dickey, J. L. (2011). Scientists can observe natural selection in action. In Campbell biology: Concepts & connections (7th ed., p. 259). Boston, MA: Benjamin Cummings.

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Human evolution: short essay on human evolution.

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Man is a product of evolution. Therefore human evolution is intimately related to the origin of life and its development on the face of earth. It is customary to speak of evolution ‘from amoeba to Man’, as if the amoeba is the simplest form of life. But in reality, there are several organisms more primitives than amoeba, say for example viruses. The evolution from a self-replicating organic molecule to a protozoan, like amoeba, is the most complex step in evolution, which might have consumed the same extent of time from protozoan to man.

The term evolution was first applied by the English philosopher Herbert Spencer to mean the historical development of life. Since then evolution denotes a change, although the term may be defined in several ways. In the context of man, the biological evolution started with the ‘Origin of life’. In the beginning, there was nothing. The first successful formation of protoplasm initiated the life and its continuous development proceeded towards complexity to give rise different life forms of evolved type.

About 10 billion years after the formation of Universe, the earth was formed. Life on earth appeared far late, nearly three billion years ago. Of the several evolutionary problems, perhaps the origin of life is the most critical, since there is no record concerning it. Life has been characterized by the capacity of performing certain vital functional activities like metabolism, growth and reproduction. There is no ambiguity regarding this point. But how the first life came on earth is a matter of conjecture.

Ancient thinkers speculated that life originated spontaneously from inorganic components of the environment, just after the formation of earth. A series of physio-chemical processes were perhaps responsible behind this creation. Aristotle (384 BC to 322 BC) was the pioneer in this line of thought and nobody raised any voice against his speculation till seventeenth Century. But in seventeenth Century, an Italian scientist, Francesco Redi (1627 -1697) made an experiment with two pieces of meat.

One of the pieces was kept fully covered and the other piece was kept in an open place. After some days he examined both of the pieces very carefully. He noticed that, flies laid eggs on the uncovered piece of meat and so many new flies had born. But the covered piece of meat had not produced any new fly, as there was absolutely no access of flies.

Redi tried to establish the fact, that living organisms cannot be originated spontaneously from inorganic components. More or less at the same time, Leuwenhock (1632 – 1723) by studying several microorganisms like protozoa, sperm, bacteria etc. under microscope declared that the spontaneous generation was possible for the microorganisms. Later, Louis Pasteur (1822 -1895) also studied much to furnish evidences in support of spontaneous creation.

In fact, scientists of this period were perplexed in finding out how life began spontaneously as a matter of chance. Philosophers, Thinkers and Scientists all had submitted their varied thought and propositions regarding the nature and mechanism of origin of life on earth. Different religions had also put forth different concepts in this connection.

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There is no scientifically accepted research that shows that humans have stopped evolving. Evolution is certainly still occurring and will continue to occur in humans. Humans exhibit differences in reproductive success, which directly leads to evolution. Humans still face challenges to survival as well, and exhibit variation in heritable traits, all characteristics of evolution. Some of the confusion on this topic likely arises because modern humans have not existed for an extensive period of time, evolutionarily speaking. Many of humanities most esteemed innovations have happened in the past decade or century, merely a few generations at most. However, no innovation will change the fact that humans exhibit varying reproductive success and challenges to survival, the components of evolution.

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Introduction
The fossil record
Structural similarities
Embryonic development and vestiges
Biogeography
Molecular biology
Early ideas
Charles Darwin
The Darwinian aftermath
The synthetic theory
Molecular biology and Earth sciences
Scientific acceptance and extension to other disciplines
Religious criticism and acceptance
Intelligent design and its critics
The concept of natural selection
The gene pool
Genetic variation and rate of evolution
Measuring gene variability
Gene mutations
Chromosomal mutations
Genetic equilibrium: the Hardy-Weinberg law
Genetic drift
Selection against one of the homozygotes
Overdominance
Frequency-dependent selection
Stabilizing selection
Directional selection
Diversifying selection
Sexual selection
Kin selection and reciprocal altruism
The concept of species
Ecological isolation
Temporal isolation
Ethological (behavioral) isolation
Mechanical isolation
Gametic isolation
Hybrid inviability
Hybrid sterility
Hybrid breakdown
A model of speciation
Geographic speciation
Adaptive radiation
Quantum speciation
Genetic differentiation during speciation
Evolution within a lineage and by lineage splitting
Convergent and parallel evolution
Gradual and punctuational evolution
Diversity and extinction
Evolution and development
DNA and protein as informational macromolecules
Distance methods
Maximum parsimony methods
Maximum likelihood methods
Evaluation of evolutionary trees
Molecular phylogeny of genes
Multiplicity and rate heterogeneity
The molecular clock of evolution
The neutrality theory of molecular evolution

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How do humans cause extinctions?
What is a human being?
When did humans evolve?

Spiral Galaxy type Sa-Sb or Sa/Sb in the constellation Virgo. The majestic Sombrero Galaxy Messier 104 (M104) or NGC 4594. The team took six pictures of the galaxy, stitched them together to create the final composite image. Photo from May-June 2003

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Stanford Encyclopedia of Philosophy - Evolution
Internet Archive - Intelligent Design and Evolution
Khan Academy - Introduction to evolution and natural selection
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National Geographic - Theory of Evolution
National Center for Biotechnology Information - PubMed Central - Science and evolution
Live Science - What is Darwin's Theory of Evolution?
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Table Of Contents

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evolution , theory in biology postulating that the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations. The theory of evolution is one of the fundamental keystones of modern biological theory.

The diversity of the living world is staggering. More than 2 million existing species of organisms have been named and described; many more remain to be discovered—from 10 million to 30 million, according to some estimates. What is impressive is not just the numbers but also the incredible heterogeneity in size, shape, and way of life —from lowly bacteria , measuring less than a thousandth of a millimetre in diameter, to stately sequoias, rising 100 metres (300 feet) above the ground and weighing several thousand tons; from bacteria living in hot springs at temperatures near the boiling point of water to fungi and algae thriving on the ice masses of Antarctica and in saline pools at −23 °C (−9 °F); and from giant tube worm s discovered living near hydrothermal vents on the dark ocean floor to spider s and larkspur plants existing on the slopes of Mount Everest more than 6,000 metres (19,700 feet) above sea level .

The virtually infinite variations on life are the fruit of the evolutionary process. All living creatures are related by descent from common ancestors. Humans and other mammals descend from shrewlike creatures that lived more than 150 million years ago; mammals, birds, reptiles, amphibians, and fishes share as ancestors aquatic worms that lived 600 million years ago; and all plants and animals derive from bacteria-like microorganisms that originated more than 3 billion years ago. Biological evolution is a process of descent with modification. Lineages of organisms change through generations; diversity arises because the lineages that descend from common ancestors diverge through time.

The 19th-century English naturalist Charles Darwin argued that organisms come about by evolution, and he provided a scientific explanation , essentially correct but incomplete, of how evolution occurs and why it is that organisms have features—such as wings, eyes, and kidneys—clearly structured to serve specific functions. Natural selection was the fundamental concept in his explanation. Natural selection occurs because individuals having more-useful traits, such as more-acute vision or swifter legs, survive better and produce more progeny than individuals with less-favourable traits. Genetics , a science born in the 20th century, reveals in detail how natural selection works and led to the development of the modern theory of evolution. Beginning in the 1960s, a related scientific discipline , molecular biology , enormously advanced knowledge of biological evolution and made it possible to investigate detailed problems that had seemed completely out of reach only a short time previously—for example, how similar the gene s of humans and chimpanzees might be (they differ in about 1–2 percent of the units that make up the genes).

greylag. Flock of Greylag geese during their winter migration at Bosque del Apache National Refugee, New Mexico. greylag goose (Anser anser)

This article discusses evolution as it applies generally to living things. For a discussion of human evolution, see the article human evolution . For a more complete treatment of a discipline that has proved essential to the study of evolution, see the articles genetics, human and heredity . Specific aspects of evolution are discussed in the articles coloration and mimicry . Applications of evolutionary theory to plant and animal breeding are discussed in the articles plant breeding and animal breeding . An overview of the evolution of life as a major characteristic of Earth’s history is given in community ecology: Evolution of the biosphere . A detailed discussion of the life and thought of Charles Darwin is found in the article Darwin, Charles .

General overview

The evidence for evolution.

How Charles Darwin developed the theory of evolution

Darwin and other 19th-century biologists found compelling evidence for biological evolution in the comparative study of living organisms, in their geographic distribution, and in the fossil remains of extinct organisms. Since Darwin’s time, the evidence from these sources has become considerably stronger and more comprehensive , while biological disciplines that emerged more recently—genetics, biochemistry , physiology , ecology , animal behaviour (ethology), and especially molecular biology—have supplied powerful additional evidence and detailed confirmation. The amount of information about evolutionary history stored in the DNA and proteins of living things is virtually unlimited; scientists can reconstruct any detail of the evolutionary history of life by investing sufficient time and laboratory resources.

Evolutionists no longer are concerned with obtaining evidence to support the fact of evolution but rather are concerned with what sorts of knowledge can be obtained from different sources of evidence. The following sections identify the most productive of these sources and illustrate the types of information they have provided.

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Books Received
Published: 08 June 1946

Essays on Human Evolution

A. D. RITCHIE

Nature volume 157 , pages 749–750 ( 1946 ) Cite this article

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IN these forty short essays, written during 1942-44, Sir Arthur Keith develops a thesis that would be vitally important if true, and in any event raises issues it would be folly to ignore. He claims (1) that men have always lived and always will live with a mixed allegiance to two incompatible codes of conduct ; one of friendliness, gentleness and cooperation within the community, the other of competition, hatred and warfare without (for example, pp. 5ff., lOOff.). (2) A community becomes a unit by isolation from its neighbours, whereby it preserves its genetic character, and it evolves as a unit (pp. 105, 130, 142). (3) The primitive unit is the tribe ; the advanced one the nation-state. Increase in size is brought about by warfare, which is part of the evolutionary process (pp. 48, 173). (4) Behaviour according to the code of 'amity' is morally approved, but 'enmity' between tribes or states is the necessary condition for human evolution ; therefore a universal community or state, even if possible, is undesirable, since it would stop the evolutionary process (pp. 45, 53).

By Sir Arthur Keith. Pp. x + 224. (London: Watts and Co. Ltd., 1946.) 15 s . net.

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Science and Creationism: A View from the National Academy of Sciences, Second Edition (1999)

Chapter: human evolution, human evolution.

Studies in evolutionary biology have led to the conclusion that human beings arose from ancestral primates. This association was hotly debated among scientists in Darwin's day. But today there is no significant scientific doubt about the close evolutionary relationships among all primates, including humans.

Many of the most important advances in paleontology over the past century relate to the evolutionary history of humans. Not one but many connecting links—intermediate between and along various branches of the human family tree—have been found as fossils. These linking fossils occur in geological deposits of intermediate age. They document the time and rate at which primate and human evolution occurred.

Scientists have unearthed thousands of fossil specimens representing members of the human family. A great number of these cannot be assigned to the modem human species, Homo sapiens. Most of these specimens have been well dated, often by means of radiometric techniques. They reveal a well-branched tree, parts of which trace a general evolutionary sequence leading from ape-like forms to modem humans.

Paleontologists have discovered numerous species of extinct apes in rock strata that are older than four million years, but never a member of the human family at that great age. Australopithecus, whose earliest known fossils are about four million years old, is a genus with some features closer to apes and some closer to modem humans. In brain size, Australopithecus was barely more advanced than apes. A number of features, including long arms, short legs, intermediate toe structure, and features of the upper limb, indicate that the members of this species spent part of the time in trees. But they also walked upright on the ground, like humans. Bipedal tracks of Australopithecus have been discovered, beautifully preserved with those of other extinct animals, in hardened volcanic ash. Most of our Australopithecus ancestors died out close to two-and-a-half million years ago, while other Australopithecus species, which were on side branches of the human tree, survived alongside more advanced hominids for another million years.

Distinctive bones of the oldest species of the human genus, Homo, date back to rock strata about 2.4 million years old. Physical anthropologists agree that Homo evolved from one of the species of Australopithecus. By two million years ago, early members of Homo had an average brain size one-and-a-half times larger than that of Australopithecus, though still substantially smaller than that of modem humans. The shapes of the pelvic and leg bones suggest that these early Homo were not part-time climbers like Australopithecus but walked and ran on long legs, as modem humans do. Just as Australopithecus showed a complex of ape-like, human-like, and intermediate features, so was early Homo intermediate between Australopithecus and modem humans in some features, and dose to modem humans in other respects. The earliest

Early hominids, such as members of the Australopithecus afarensis species that lived about 3 million years ago, had smaller brains and larger faces than species belonging to the genus Homo, which first appeared about 2.4 million years ago. White parts of the skulls are reconstructions, and the skulls are not all on the same scale.

stone tools are of virtually the same age as the earliest fossils of Homo. Early Homo, with its larger brain than Australopithecus, was a maker of stone tools.

The fossil record for the interval between 2.4 million years ago and the present includes the skeletal remains of several species assigned to the genus Homo. The more recent species had larger brains than the older ones. This fossil record is complete enough to show that the human genus first spread from its place of origin in Africa to Europe and Asia a little less than two million years ago. Distinctive types of stone tools are associated with various populations. More recent species with larger brains generally used more sophisticated tools than more ancient species.

Molecular biology also has provided strong evidence of the close relationship between humans and apes. Analysis of many proteins and genes has shown that humans are genetically similar to chimpanzees and gorillas and less similar to orangutans and other primates.

DNA has even been extracted from a well-preserved skeleton of the extinct human creature known as Neanderthal, a member of the genus Homo and often considered either as a subspecies of Homo sapiens or as a separate species. Application of the molecular clock, which makes use of known rates of genetic mutation, suggests that Neanderthal's lineage diverged from that of modem Homo sapiens less than half a million years ago, which is entirely compatible with evidence from the fossil record.

Based on molecular and genetic data, evolutionists favor the hypothesis that modem Homo sapiens, individuals very much like us, evolved from more archaic humans about 100,000 to 150,000 years ago. They also believe that this transition occurred in Africa, with modem humans then dispersing to Asia, Europe, and eventually Australasia and the Americas.

Discoveries of hominid remains during the past three decades in East and South Africa, the Middle East, and elsewhere have combined with advances in molecular biology to initiate a new discipline—molecular paleoanthropology. This field of inquiry is providing an ever-growing inventory of evidence for a genetic affinity between human beings and the African apes.

Opinion polls show that many people believe that divine intervention actively guided the evolution of human beings. Science cannot comment on the role that supernatural forces might play in human affairs. But scientific investigations have concluded that the same forces responsible for the evolution of all other life forms on Earth can account for the evolution of human beings.

While the mechanisms of evolution are still under investigation, scientists universally accept that the cosmos, our planet, and life evolved and continue to evolve. Yet the teaching of evolution to schoolchildren is still contentious.

In Science and Creationism , The National Academy of Sciences states unequivocally that creationism has no place in any science curriculum at any level.

Briefly and clearly, this booklet explores the nature of science, reviews the evidence for the origin of the universe and earth, and explains the current scientific understanding of biological evolution. This edition includes new insights from astronomy and molecular biology.

Attractive in presentation and authoritative in content, Science and Creationism will be useful to anyone concerned about America's scientific literacy: education policymakers, school boards and administrators, curriculum designers, librarians, teachers, parents, and students.

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Essay on Human Evolution: Top 6 Essays | Biology

Essay on Human Evolution

Essay # 1. Introduction to Human Evolution:

Essay # 2. Origin of Apes and Hominids:

Essay # 3. H istory of the Primates:

Essay # 4. Genus of Homo:

Essay # 5. Evolution of Neanderthals :

Essay # 6. Models of Human Evolution:

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Fourteen Discoveries Made About Human Evolution in 2022

Animal friends and animal food: origins of domestication and cooperation

New fossils shed light on old ancestors: discoveries from our earliest and most recent evolutionary history

Friends and family ties in modern apes and Neanderthals

How disease shapes us, and how we evolved to treat it

Most notable: a new 2022 Nobel Laureate

Biology archive

Evidence for evolution

Key points:

Introduction