Cultural Anthropology Chap 4 Becoming Human

Chapter 4Becoming Human: The Origin and Diversity of our Species

Anthropologists gather information from a variety of sources to piece together an understanding of evolutionary history and humankind’s place in the animal kingdom.

Studies of living primates (our closest mammal relatives), ancient fossils, and even molecular biology

biology contribute to the story of how humans evolved.

On one level, human evolutionary studies are wholly scientific, formulating and testing hypotheses about biological and behavioral processes in the past.

At the same time, like all scientists, anthropologists are influenced by changing cultural values.

Thus, PALEOANTHROPOLOGISTS, who study human evolutionary history, and PRIMATOLOGISTS, who study living primates, as well as the physical or biological

anthropologists who study contemporary biological diversity, must be critically aware of their personal beliefs and cultural assumptions as they construct their theories.

EVOLUTION THROUGH ADAPTATION In a general sense, EVOLUTION

(from the Latin word evolutio, literally meaning “unrolling” or “rolling forth”) refers to change through time.

Biologically, it refers to changes in the genetic make up of a population over generations.

While some evolution takes place through a process known as ADAPTATION – a series of beneficial adjustments of organisms to their environment, random forces also contribute critically to evolutionary change.

Adaptation is the cornerstone of the theory of evolution by NATURAL SELECTION, originally formulated by English naturalist CHARLES DARWIN in 1859.

In this theory, individuals having biological characteristics best suited to a particular environment survive and reproduce with greater

greater frequency than do individuals without those characteristics.

Unique among humans is the biological capacity to produce a rich array of CULTURAL ADAPTATIONs, a complex of ideas, activities, and technologies that enable people to survive and even thrive in their environment.

Early humans, like all other creatures, greatly depended on physical attributes for survival.

But in the course of time, humans came to rely increasingly on CULTURE as an effective way of adapting to the environment.

They figured out how to manufacture and utilize tools; they organized into social units that made serve and share their traditions and knowledge through the use of symbols that ultimately included spoken language.

The ability to solve a vast of vast array of challenges through culture has made our species unusual among creatures on this planet.

Humans do not merely adapt to the environment through biological change; we shape the environment to suit human needs and desires.

Today, computer technology enables us to organize and manipulate an ever-increasing amount of information to keep pace with the environmental changes we have wrought.

Space technology may enable us to propagate our species in extraterrestrial environments.

Biomedical technology may eventually enable us to control genetic inheritance and thus the future course of our biological evolution.

The fundamental elements of human culture came into existence about 2.5 million years ago.

HUMANS AND OTHER PRIMATES

Humans are one of 10 million species on earth, 4,000 of which are fellow mammals.

Species are populations or groups of populations having common attributes and the ability to interbreed and produce, live, fertile offspring.

Different species are reproductively isolated from one another.

Human species are one kind of PRIMATE., a subgroup of mammals that also includes lemurs, lorises, tarsiers, monkeys, and apes.

Among fellow primates, humans are most closely related to apes – chimpanzees, bonobos, gorillas, organgutans, and gibbons – all of particular interest to primatologists.

European scientists have argued long and hard over issues of species classification, especially since the start of the Age of

Exploration about 500 years ago that brought them to distant lands inhabited by life forms they had never before seen, including apes.

In 1698, after dissecting a young male chimpanzee captured in West Africa and brought to Europe, and English physician concluded the creature was almost human and

classified it as HOMO SYLVESTRIS (“Man of the Forest”).

A few decades later, Swedish naturalist CAROLUS LINAEUS (1707-1778) published the first edition of his famous System of nature (1735).

In it, he classified humans with sloth and monkeys in the same order: ANTHROPOMORPHA (human-shaped).

From the time Linnaeus published the tenth edition of his famous book in 1758, he had replaced the name “Anthropomorpha” with “PRIMATE” and included bats,

lemurs, monkeys, and humans in that category.

He now recognized not just one human species but two: HOMO SAPIENS OR HOMO DIURNUS (Active during daylight) and an apelike human he called HOMO NOCTURNUS (Active during night).

He referred to the HOMO NOCTURNUS as HOMO TROGLODYTES (Human cave-dweller).

European scientist debated on the proper classification of the great apes.

The famous Scottish Judge LORD MANBODDO argued in 1770s and 1780s that orangutans should be considered part of the human species.

He pointed out that they could walk erect and construct shelters and that they used sticks to defend themselves.

Humans have a long evolutionary history as mammals and primates that set the stage for the cultural beings we are today.

By studying our evolutionary history as well as the biology and behavior of our closest living relatives, we gain better understanding of how and why humans developed as they did.

Evidence from ancient skeletons indicates the first mammals appeared over 200 million years ago as small nocturnal (night-active) creatures.

The earliest primate like creatures came into being about 65 million years ago when a new, mild climate favored the spread of

dense tropical and subtropical forests over much of the earth.

The change in climate and habitat, combined with the sudden extinction of dinosaurs, favored mammal diversification, including the evolutionary development of arboreal (tree-living) mammals from which primates evolved.

The ancestral primates possessed biological characteristics that allowed them to adapt to life in the forest.

Their relatively small size enabled them to use tree branches not accessible to larger competitors and predators.

Arboreal life opened up an abundant new food supply.

The primates were able to gather leaves, flowers, fruits, insects, bird eggs, and even nesting birds.

Natural selection favored those who judged depth correctly and gripped the branches tightly.

Those individuals who survived life in the trees passed on their genes to the succeeding generations.

Although the earliest primates were nocturnal, today most primate species are diurnal (active in the day).

The transition adjustments that helped shape the biology and behavior of the humans today.

ANATOMICAL ADAPTATION Primate definition

The varied diet available to arboreal primates – shoots, leaves, insects, and fruits – required relatively unspecialized teeth, compared to those found in other mammals.

Mammal ancestral possessed three incisors, one canine and three premolars, and three molars on each side of the jaw, top and bottom for a total of forty-four teeth.

The incisors were used for gripping and cutting.

Canines for tearing and shredding.

Molars and premolars for grinding and chewing food.

SENSORY ORGANS The primates’ adaptation to

arboreal life involved changes in the form and function of their sensory organs.

The sense of smell was vital for the earliest ground dwelling, night-active mammals. It enabled them to operate in the dark, to sniff out their food, and to detect hidden predators.

For active tree life during daylight, good vision is a better guide than smell in judging the location of the

branch or tasty morsel. Accordingly, the sense of smell declined in primates, while vision became highly developed.

Traveling through trees demands judgments concerning depth, direction, distance, and the relationships of objects hanging in space, such as vines or branches.

Monkeys and apes achieved this through binocular stereoscopic color vision, the ability to see the world in the three dimensions of height, width, and depth.

Tree-living primates also possess an acute sense of touch. An effective feeling and grasping mechanism helps keel them from

falling and tumbling while speeding through the trees.

The early mammals from which primates evolved possessed tiny touch-sensitive hairs at the tips of their hands and feet.

THE PRIMATE BRAIN An increase in brain size,

particularly in the cerebral hemispheres- the areas supporting conscious thought- occurred in the course of primate evolution.

In monkeys, apes, and humans the cerebral hemispheres completely cover the cerebellum, the part of

brain that coordinates the muscles and maintains body balance.

THE PRIMATE SKELETON The skeleton gives vertebrates –

animals with internal backbones-their shape of silhouette, supports the soft tissues, and helps protect vital internal organs.

The limbs of the primate skeleton follow the same basic ancestral plan seen in the earliest vertebrates.

The upper portion of each arm or leg has a single long bone, the lower portion has two bones, and then hands or feet with five radiating digits.

In the apes, a sturdy collarbone orients the arms at the side rather than the front of the body. With their broad flexible shoulder joints, apes can hang suspended from tree branches and swing from tree to tree.

The retention of the flexible vertebrate limb pattern in primates was a vulnerable asset to evolving humans. It was, in part, having hands capable of grasping, that enabled our own ancestors to manufacture and use tools and thus alter the course of their evolution.

BEHAVIORAL ADAPTATION Primates adapt to their

environments not only anatomically but also through a wide variety of behaviors.

Young apes spend more time reaching adulthood than do most other mammals.

During their lengthy growth and development, they learn the

behaviors of their social group. While biological factors play a role

in the duration of primate dependency, many of the specific behaviors learned during childhood derive solely from the traditions of the group.

The behavior of primates, particularly apes, provides

provides anthropologists with clues about the earliest development of human cultural behavior.

Many studies of the behavior of apes in their natural habitat have been undertaken to provide models to reconstruct the behavior of evolving humans.

While no living primate lives exactly as our ancestors did, these studies have revealed remarkable variation and sophistication in ape behavior.

Primatologists increasingly interpret these variations as cultural because they are learned rather than genetically programmed or instinctive.

CHIMPANZEE AND BONOBO BEHAVIOR

Chimpanzees and bonobos are highly social animals.

Among the chimps, the largest social organizational unit is the community, usually composed of 50 or more individuals who inhabit a large geographic area.

They are found singly or in small subgroups consisting of adult males, or females with their young, or males and females together with young.

Relationships among individuals within the ape communities are relatively harmonious.

They noted that physical strength and size play a role in determining an animal’s rank.

Chimpanzee females sometimes hunt, but males do so far more frequently.

Whatever the nutritional value of meat, hunting is not done purely for dietary purposes, but for social and sexual reasons as well.

Hunts usually take place during dry season.

For female chimps ready

for pregnancy, a supply

of protein-rich food

benefits her physical condition during a period of increased nutritional requirements.

Chimpanzees and bonobos have not only developed different hunting strategies, but also different practices.

CHIMPANZEES AND BONOBO CHILDHOOD DEVELOPMENT

Chimpanzee and bonobo dependence on learned social behavior is related to their extended period of childhood development.

Bonobo young learns by observation, imitation, and practice

how strategically interact with others and even manipulate them for his or her own benefit.

Young chimpanzees also learn other functional behaviors from adults, such as how to make and use tools.

HUMAN ANCESTORS

Humans as classified as HOMINIDS, the broad-shouldered tailless group of primates that includes all living and extinct apes and humans.

Humans and their

ancestors are distinct

among the hominoids for

BIPEDALISM – a specialized

form of locomotion in which an organism walks upright on two feet.

Larger brains and bipedal locomotion constitute the most striking differences between humans and our closest primate relatives.

The First Bipeds

Between 5 and 15 million years ago, various kinds of hominoids lived throughout Africa, Asia and Europe.

One of these apes living in Africa between 5 and 8 million years ago was a direct ancestor to the human line.

The 6 million-year-old ORRORIN fossils discovered in Kenya in 2001 or the 6 to 7 million-year-old skull discovered in Chad, Central Africa is proposed as the latest missing link in the evolutionary chain leading to humans.

Bipedalism is required as evidence.

Between 4 and 5 million years ago, the environment of eastern and southern Africa was mostly a mosaic of open country with pockets of closed woodland.

Some early bipeds seem to live in one of the woodland

pockets.

Later human ancestors inhabited more open country known as savannah – grasslands with scattered trees and groves – and are assigned to one or another species of the genus AUSTRLOPITHECUS (from Latin asutralis, meaning “southern” and Greek pithekos, meaning “ape”.)

None of the australopithecines were as large as most modern humans, although all were much more muscular for their size.

Bipedalism is considered an important adaptive feature

in savannah environment.

EARLY HOMO

Increased meat consumption by our early ancestors was important for human evolution.

On the savannah, it is hard for a primate with a humanlike digestive system to satisfy protein requirements from available plant resources.

Moreover, failure to do so has serious consequences: stunted growth, malnutrition, starvation and death.

The earliest identifiable stone tools have been found in Africa, often in the same geographical strata

as the earliest HOMO

fossils.

They include flakes and choppers. Flakes were obtained from a “core”

stone, effective by striking it with another stone or against a large rock.

The flakes that broke off from the core had two sharp edges, effective for cutting meat and scrapping hides.

Leftover cores were transformed into choppers, used to break open bones.

The appearance of stone flakes and choppers marks the beginning of the LOWER PALEOLITHIC, the

first part of the Old Stone

Age.

All of these early Lower Paleolithic tools are part of the OLDOWAN TOOL tradition, a name first given to the tools found at Olduvai Gorge in the 1960s.

Since major brain-size increase and tooth size reduction

are important trends in

the evolution of the genus,

HOMO HABILIS (“handy Human”) which appeared around 2.5 to 2.6 million years ago, about the same time as the earliest evidence of stone tool making.

TOOLS, FOOD, AND BRAIN EXPANSION Sometimes, natural selection

produces change more gradually. This appears to have taken place

following the arrival of HOMO HABILIS, the first species in the genus HOMO; with the

demonstrated use of tools

our human ancestors began a cou

a course a gradual brain expansion that continued until some 200,000 years ago.

Tool making itself puts a premium on manual dexterity as opposed to hand use emphasizing power.

HOMO ERECTUS AND THE SPREAD OF THE GENUS HOMO Shortly after 2 million years ago, at

a time that HOMO HABILIS and OLDOWAN tools had become widespread in Africa, a new species HOMO ERECTUS (Upright human) appeared on that continent.

Unlike homo habilis, however, homo erectus did not remain confined to Africa. Because the fossil evidence also suggests some differences within and among populations of homo erectus inhabiting

discrete regions of

Africa, Asia, and Europe.

The homo erectus emerged with the beginning of the Pleistocene epoch or Ice Age.

Available fossil evidence indicates that homo erectus had a body size and proportions similar to modern humans, though with heavier musculature.

Remains found in Southern Africa suggest that homo erectus may have learned to use fire by 1 million years ago.

Fire gave our human ancestors more control over their environment. It allowed

them to continue their

activities after dark.

The ability to modify food culturally through cooking may have contributed to the eventual reduction in the tooth size and jaws.

With homo erectus also have evidence of organized hunting as the means for procuring meat, animal hides, horn, and bone.

Social organization and technology developed along with an increase in brain size and complexity and a reduction in tooth and jaw size.

The appearance of cultural adaptation such as controlled use of fire, cooking, and more complex tool kits may have facilitated language development.

THE BEGINNINGS OF HOMO SAPIENSTHE NEANDERTAL DEBATE The record is particularly rich when

it comes to the Neandertals, a distinct and certainly controversial ancient member of the genus HOMO.

Typically, they are rep-

resented as the classic

“cave men”, stereotyped

In Western popular media and even in natural history museum displays as wild and hairy club-wielding brutes.

Neandertals were a distinct and extremely muscular group within the genus Homo.

Many aspects of the Neandertal’s unique skull shape and body form

skull shape and body form represent its biological adaptation to an extremely cold climate.

Its intellectual capacity for cultural adaptation was noticeably superior to that of earlier members of the genus HOMO.

Neandertal’s extensive use of fire was essential to survival in a cold climate.

They lived in small bands or single-family units, both in the open and in caves, probably communicating through language.

The tool-making tradition of all but the latest Neandertals is called the MOUSTERIAN tradition after a site (Le Moustier) in the Dordogne region of southern France.

Improved cultural adaptive abilities relate to the fact that the

brain had achieved modern size.

Anatomically Modern Peoples and the Upper Paleolithic Humans began to manufacture

tools for more effective hunting and fishing, as well as gathering.

Cultural adaptation also became more highly specific and regional, thus enhancing human chances for survival under a wide variety of environmental conditions.

The degree of specialization required improved manufacturing techniques.

The blade method of manufacture required less raw material than before and resulted in smaller and lighter tools with a better

ration between weight of

flint and length of cutting edge.

Art was an important aspect of Upper Paleolithic culture.

Humans had not produced representational artwork before.

In some regions, tools and weapons were engraved with beautiful animal figures; pendants were made of bone and ivory, as were female figurines.

Spectacular paintings and engravings depicting humans and animals of this period have been found on the walls of caves and rock shelters in Spain, France, Australia, and Africa.

Hypotheses on the Origins of Modern Humans Multiregional hypothesis argue that

the fossil evidence suggests a simultaneous local transition from homo erectus to modern homo sapiens throughout the parts of the world inhabited by early members of the genus Homo.

By contrast, those supporting the recent African origin hypothesis use genetic and other evidence to argue that all anatomically modern humans living today descend directly from one single population of archaic Homo Sapiens in

Africa.

The first argue that our human ancestors began moving into Asia and Europe as early as 1.8 million years ago, while the second hypothesis maintains that anatomically modern homo sapiens evolved only in Africa, completely replacing other members of the genus Homo as they spread throughout the world.

The End

Topics of Discussion

State the main ideas you’ll be talking about

Topic One

Details about this topic Supporting information and

examples How it relates to your audience

Topic Two

Details about this topic Supporting information and

examples How it relates to your audience

Topic Three

Details about this topic Supporting information and

examples How it relates to your audience

Real Life

Give an example or real life anecdote

Sympathize with the audience’s situation if appropriate

What This Means

Add a strong statement that summarizes how you feel or think about this topic

Summarize key points you want your audience to remember

Next Steps

Summarize any actions required of your audience

Summarize any follow up action items required of you