From the TIME Magazine 23 July 2001. These slides are based on the notes in your textbook “Designs of Life by Meg Bayley. Make sure your read all the

From the TIME Magazine 23 July 2001

These slides are based on the These slides are based on the notes in your textbook notes in your textbook “Designs of Life by Meg Bayley.“Designs of Life by Meg Bayley.

Make sure your read all the material in Chapter 16 p272 - 298.

Sites of early Human evolution.

The main physical difference between humans and apes stem from the differences between quadrupedalismquadrupedalism and bipedalismbipedalism.

A chimp's lumbar region, or lower spine, is short and stiff; a human's is longer and curved to push the torso’s center of gravity forward so that it lies over the feet.

1

Chimps sway when they walk upright because lifting one leg off the ground throws them off balance; humans prevent such swaying with a broader pelvis and a specialized hip joint and its associated muscles.

2

In chimps, the femur runs straight from hip to knee. The human femur angles inward, moving support more directly under the torso.

3

To support the human body's weight, the femur is larger at the bottom and the tibia is larger at the top. A groove at the bottom of the inward-angled femur keeps the patella from sliding off.

4

A chimp's big toe is opposable, like a thumb, allowing the chimp to grasp with its feet. A human's big toe is lined up with the other four toes - bad for climbing but good for forming an arch that runs from front to back. The arch acts as a shock absorber, detecting impacts that would otherwise travel up the leg. This enables humans to walk long distances and run with less chance of injury.

5

1 Australopithecines were bipedalbipedal.

A. afarensis had the articulation of the femur, etc., that showed they walked upright, although the pelvis blade was further back.

General features of the General features of the

AustralopithecinesAustralopithecines

Laetoli hominid Laetoli hominid footprintsfootprints

2 The foot was arched, i.e. it had curved metatarsals.

3 They had hominid teeth (two cusps to the premolars), but ape-like jaws.

4 A small brain (approx. 450 cm3).

5 The skull had no nose bone or chin.

Australopithecus Paranthropus africanus robustus

6 There is only debatable evidence that they made tools, and no evidence that they had home bases or shared food. They were probably opportunist feeders.

7 They could not talk as we know it, but would have had body language, gestures, facial expressions and sounds to communicate.

Australopithecus Australopithecus afarensisafarensis

‘Lucy’

* ‘Lucy’ 1.1 m high

* About 30 kg

* Dense limb bones suggest great muscular strength

* Face ape-like, low forehead, bony ridge over eyes, flat nose & no chin


‘Lucy’

* Brain about 1/3 size of a human brain

* Walked on two legs but also partly arboreal.

* Angle of femur brought her legs under her body


* Her flaring pelvis had gluteal muscles to the side of the thigh for stability.

* Femoral condyle provided a large flat surface to transmit weight.

* Footprints suggest she drove off her foot from the big toe.


* She had long arms and short legs.

* Her foot was arched.

* She did not make stone tools. She may have used sticks and bone but these would not leave fossils.

* Possibly scavenged meat from carnivores and caught small prey to add to diet of fruits, nuts, tubers and other vegetables.


* Afarensis survived from 3.8 to 3 million years ago and then disappeared.

* She lived in the dry open uplands of Laetoli and the wooded shores of Hadar.

* Females smaller than males - sexual dimorphism


* Would appear hairy to us.

* Skin probably dark - adaptation to tropical sun.

* She did not have articulated speech

* Scientists believe she has enough ‘human traits’ to make her an ancestor of ours.

Australopithecus Australopithecus africanusafricanus

* Very like Australopithecus afarensis.

* Lived from 3 to 2.2 million years ago (mya).

* Had sexual dimorphism.

Taung Child

* Males 1.4 m & females 1.2 m high.

* Teeth more modern than A. afarensis.


* Brain slightly larger than A. afarensis.Approximately 442 cm3.

* Skeleton almost the same as A. afarensis. More bones found to prove it definitely walked upright.

Taung Child

* Skull less primitive to A. afarensis. Face shorter & less protruding below the nose.


* Lower jaw is larger & stronger than in modern humans.

Taung Child

* Teeth evidence suggests A. africanus babies matured more rapidly than modern human babies.

Genus HomoGenus Homo

General Features of the Genus HomoGeneral Features of the Genus Homo

* Change in shape & size of the skull, jaws and teeth.

* Increase in complexity of the brain.

* Proportional lengthening of the legs in relation to the length of the trunk and arms.

* Development of the S-curvature of the spine.

Genus HomoGenus Homo

General Features of the Genus HomoGeneral Features of the Genus Homo

* Development of speech.

* Development of deliberate tool making.

* Gradual development of group living and culture.

Break away from Australopithecines may have been due to great climatic changes. About 2 mya, the Earth had a cool period and accompanying drought. This lead to the extension of the grasslands and a dwindling of the forests.

Homo habilis (Handy Man)Homo habilis (Handy Man)

* Fossils found in the Olduvai Gorge.

* Height 1.2 - 1.5 m

* Weight 25 - 35 kg

* Face is still primitive , but lower back teeth are narrower


* Brain is more sophisticated - a bulge in the Broca’s area.This is the part of the brain involved with speech. Probablycouldn’t talk but may have made sounds.

* Brain between 680 -775 cm3

i.e. Larger than A. africanusA. africanus

Broca’s area

Wernicke’s area


Adult cranial capacity (range in cm3)

Chimpanzees 300-500

Australopithecines 400-530

Early transitional 500-750 humans

Modern humans 900-2300


* Teeth smaller, have thinner enamel and the dental jaw shape is more ‘V’ shaped than the Australopithecines.

* Skull is more rounded, face smaller and protrudes less. Jaw muscles reduced in size.

* No sexual dimorphism in canines or body size.


* Change in the pelvic structure - giving them a more upright position.

* They were bipedal..

* Lived about 2 - 1.6 mya.

CultureCulture

* H. habilis was a successful hunter.

They made stone tools.


* They made simple stone tools - ‘Oldowan tools. These were rounded stones with one end chipped. The flakes that were chipped off were probably also used.

* Stones often carried many miles from their point of origin.

CultureCulture


* H. habilis used their hands for clubbing, throwing, butchering game, preparing skins and for digging roots, etc.

* Made some sort of shelter or windbreak.

CultureCulture

* Bands consisted of about 12 people.Must of had co-operative behaviour.


* With the development of primitive speech their communication would have improved.

* As the pelvis shape change and the human line developed bigger brains the problem of giving birth to a larger headed baby arose. Overcome by giving birth to a very immature baby. Aftercare now required.

CultureCulture

Homo erectus (Upright Man)Homo erectus (Upright Man)

The earliest Homo erectus apparently were contemporaries of the late Homo habilis in East Africa for several hundred thousand years. This suggests that the immediate ancestor of Homo erectus was an early Homo habilis or even another yet to be discovered species of early humans.

Java man and Peking ManJava man and Peking Man





* Oldest fossil dated about 1.6 mya.

* First fossil found in Java 1891.

* H. erectus gave way th H. Sapiens at about 300 000 years ago.

* Prior to this H erectus moved out of its ancestral homelands.



* Reason for moving out - “They left “They left when they did because they when they did because they wanted to, because they had to, wanted to, because they had to, and especially, because they and especially, because they could.”.could.”.

* Large variation in the populations - maybe the east and west species should be different species.

Asian - H erectus African - H ergaster


Physical EvolutionPhysical Evolution

* Face similar to H. habilis

a protruding jaw

no chin

thick brow ridges

a long, low, thick skull that narrows behind the eyes

a broad flat face


* Unlike H. habilis it had :

a smaller face

a higher skull

a smaller ramus of the lower jaw

smaller teeth

an inner ear system like ours



* Brain had enlarged considerably to 1000 cm3. (Modern man 1350 cm3.

* Taller than H. habilis - 1.8 m as an adult. (1.5 - 1.8 m) Weight 40 - 70 kg.

* First of the hominids to have a nose that stuck out from the face with the nostrils pointing downwards.



* Larger brain - probably had more advanced speech.

* Evidence of charcoal at sitessuggests they had learnt to control fire.

* First of the hominids to have a nose that stuck out from the face with the nostrils pointing downwards.

Cultural EvolutionCultural Evolution


* They made large teardrop-shaped, double edged ‘hand axes’.The Acheulian tools. More advanced as compared to Oldowan tools.


Percussion Flaking

Techniques:

hard hammer (left) and soft hammer (right)



Examples of Acheulian hand axes


Cultural EvolutionCultural Evolution* Increased brain meant more

curiosity so they started to migrate to other areas.

* Able to exploit the environment better - able to move into what were marginal areas. Moved through Africa, Asia and Europe.

* Probably needed to move because increased populations would use up resources.


Cultural EvolutionCultural Evolution* Evidence in Europe that they built

shelters.

* Suggestions that H erectus was a serious hunter. Lots of hand axe tools near large accumulations of bones. Also when bones are scraped by flakes they leave marks.

Fire can be used to:Fire can be used to:

* kill bacteria and parasites in food

* to make food easier to eat and digest

* light up the camp and scare away wild animals

* give warmth - allow nomadic H. erectus to move into colder areas.* provide an atmosphere to help group formation and co-operation.

Homo sapiens Homo sapiens

* 3 sub species :

Early H. sapiens Early H. sapiens considered to be considered to be less than half a less than half a million years old.million years old.

archaic H. sapiens

H. Sapiens neanderthalensis

H. Sapiens sapiens

Neandertal ModernNeandertal Modern human human

Clear that the development of upright bodies and bipedal locomotion came before the evolution of the large human brain.

* Full bipedalism by about 2.5 million years ago.

* Size of our brains continued to increase in a punctuated evolutionary pattern.

* Period beginning around 1.8 million years ago where little change occurred.

Late gracileaustralopithecine

Homo habilis

Homo erectus

Homo sapiens

440 cm3 680 - 775 cm3 1000 cm3 1300 cm3

Change in Brain Change in Brain SizeSize

Increase in volume of the brain vault.

* About 600,000 years ago humanbrain size began to grow very rapidly.

* This trend continued until 100,000-75,000 years ago.

* We continued to evolve above the neck after the rest of the body essentially reached its modern form.

Archaic Homo sapiensArchaic Homo sapiens


Brow ridge

Occipital bun

* Appeared about 400 000 to 200 000

years ago.* Hominids with larger brains (1200 cm3 ) and more rounded skulls.

* Still had a jaw that stuck out, a long low skull, no chin and very large brow ridges.

Archaic Homo sapiensArchaic Homo sapiens


* Tools similar to Acheulian tools used hy H. erectus.

* They used fire.

* Drove herds off cliffs.

* They built shelters.

Homo sapiens neanderthalensisHomo sapiens neanderthalensis


* Had thick heavy bones with markings of heavy muscles.

* Had short lower limbs like the Eskimos. (An adaptation to cold weather possibly.)

* Large heads with prominent brow ridges over their eyes, reduced chins, large noses, and protruding jaws.



* height about 1.7 m and Weight about 70 kg.

* Brain larger than that of modern humans - 1500 cm3.

* Teeth showed rounding wear. May have been caused by holding skins in their teeth as they worked with them.



* Intelligent, able to adapt to extremes of weather. Evidence to suggest they had leant to use hot rocks for cooking.

* Survived the cold winters with clothes and heated homes. Lived in caves or built low stone walls. Also evidence they used skins over entrance ways.



* Made fine stone tools.‘Mousterian’ tools.

* They included flakes, scrapers, spears and bolas stones (two stones joined with a length of hide rope.)

* Bolas used to bring animals down. Still used in Argentina today.

Mousterian Tradition hide scraperMousterian Tradition hide scraper (left) and spear pointspear point (right) (both were made from Levallois flakes)


Mousterian Tradition hand axe

Neandertal Awl




* Herds driven off cliffs or into bogs.

* Bones found suggest they hunted for large animals such as bison, cave bears, horses, reindeer, wild cattle, woolly mammoths and wooly rhinoceroses. Small animals caught would have included foxes, hares, birds and fish.



* Some animals would be caught for fur, bones and sinews to make clothes, tents and snares.

* They dressed hides for clothing.

* They buried their dead, often with flowers and tools.

* They had strong social bonds.

* Evidence that they were cannibals.

In Millions of Years (All dates are approximate)

In Millions of Years (All dates are approximate)

Documents

From the TIME Magazine 23 July 2001. These slides are based on the notes in your textbook “Designs of Life by Meg Bayley. Make sure your read all the