The Human Transition - PowerPoint Presentation

Slide1

The Human TransitionSlide2

2 million years ago

Bipedal hominids with specialized teeth and expanded brains were walking around East Africa

Some made

artifacts out of wood, stone, bone, and they used fireFemales played active rolesPerhaps the first food sharing happened between mother and childSlide3

Homo Species

Early

Homo

brains range from 510 to 75ocm cubedCranium has thinner bone and is more roundedFace is flatterTeeth and jaws are less ruggedIncludes: Homo erectus, Homo habilis

, Homo heidelbergensis, Homo ergaster

, Homo floresiensisSlide4

Earliest Evidence of Culture

Stone tools are the greatest evidence we have, some 2.5 million years old!

Bone and tool evidence shows that rather than hunting for meat, early humans scavenged carcasses killed by carnivoresSlide5

Homo erectus

Coexisted in eastern Africa with other primate species

They were here 1.8 million years ago up until 500,000 years ago

Brain capacity was around 1000cm cubedStarted to migrate out of Africa (went towards Russia and China)The oldest fossil is a skeleton of a boy that is 1.7 million years oldHe was tall and slim, and probably hairless so that he could sweat lots and cool off in the heat

It appears as though breathing was not as advanced, suggesting that they may not have been able to talk the way we canSlide6
Slide7

The Culture of

Homo erectus

Used fire and stone tools

Hard to tell if they hunted large animals...bones have been found but its very hard to say where they came from Skull damage may suggest cannibalismEndurance running became important. Adaptations such as these became necessary:

Energetics(the flow and transformation of energy)Stabilization (how the body keeps from falling)

Temperature regulation (maintaining body temp)Slide8

Importance of Fire

The transition to

Homo erectus

was driven by fireStarted cooking their food which changed everything!New diet resulted in smaller guts, bigger brains, bigger bodies, reduced body hair, and smaller teeth (since cooked food is softer)Slide9

Homo erectus to

Homo sapiens

1 proposal: Replacement Theory: Although

Homo erectus were dispersed among Africa, Asia, and Europe, only one group (in Africa) evolved into Homo sapiens. This happened 100,000-200,000 years ago

Homo sapiens then travelled the globe and replaced any Homo erectus still living

They then evolved into the different races we see globally2nd proposal: Multiregional Continental Theory: Several different migrations out of Africa by populations that looked different occurred. These migrations took place during different times using different routes. They evolved into the human species today independentlySlide10

Who were the Neandertals

?

They were not

Homo sapiens, but they did belong to the genus HomoThey lived 135,000 years ago up until about 35,000 years agoThey had massive brains! (1,520cm cubed)Mostly right handed

Lots of muscleMany argue that Homo neandertalensis

should actually be Homo sapiens neandertalensisSlide11

Neandertals Continued....

Used wooden spears

Drove animals off cliffs

Bones of elephants and rhinos were used for buildingsLots of bones with torn off flesh, cuts, bite marks...not sure why....Had light skin and red hair (DNA shows)Lived in Europe and Western AsiaSlide12

Modern Humans

Anatomically modern human fossils have been found in Africa and Asia that are around 70,000 years old

Modern skeletal remains were found in Ethiopia that dated 160,000 years ago!

DNA evidence shows that modern humans are around 100,000-200,000 years oldSo they lived at the same time as Neandretals, but in different areas.Slide13

So What Happened to the

Neandertals

?

There was no conquest or exterminationMay have evolved into anatomically modern people, adopting stone-age culture, but this is unlikelyMay have retreated and died out as modern people spread through EuropeMay have interbred with migrating modern peopleNo one really knows...they are still debating...Slide14

Anatomically Modern Traits of

Homo sapiens

sapiens

Our teeth, brow ridges, and face are smaller, evidence of less chewing stress (probably because we have awesome tools now to help )Our brain is large, although not as large as some of our ancestors

We have a distinct chin, again possibly related to less chewing stressOur bones are longer and thinnerOur body is lankier and less robust (probably because we don’t work as hard)Slide15

Behaviorally

Modern Traits of

Homo sapiens

sapiensSymbolism (using one object or sign to mean something else)Oldest use of symbols in in South Africa’s 70,000 year old Blombos cave, where there are dozens of stone tablets that have clearly been scratched with X’s and O’s

In Israel’s Skhul Cave, ten humans were buried 100,000 years ago and were wearing snail shell necklaces!

Complex language (communicating by stringing together messages according to complex rules, syntax, and grammar)Slide16

Origins of Language

Most anthropologists study the “Social Grooming Theory”, as it is most supported

Most primates communicate and maintain relationships by grooming each other (picking off insects and debris from each other)

Over time, this became more complex as social group sizes increasedLarger group size is correlated to having a bigger brain!As group size became larger, language replaced physical groomingLanguage conveys more information than grooming, and can address more than one person at a timeSlide17

Evolution of Consciousness

Consciousness-is the unique human capacity for self-contemplation. (Not only do we think, but we can think about what we think)

Mithen

Model-evolution of consciousness came about as the mind forged new links between previous intelligences that were isolated. There are 4 intelligences that have come about in human evolution:

1. Social intelligence (complex interpersonal primate relationships)2. Technical intelligence (ability to make and use tools)3. Linguistic intelligence (manage complex communication)

4. Natural history intelligence (understand cause and effect relationships)Donald Model-evolution of consciousness came in a series of drastic changes in the mind’s way of storing and representing experiences1. Episodic consciousness (all primates had this before Homo)2. Mimetic consciousness (miming and simple vocalizations of the first Homos)3. Mythic consciousness (symbol use, myths, and narratives to organize complex and diverse ideas in the mind)4. Theoretic consciousness (invention of objective science, rather than believing in the supernatural, about 2000 years ago in Greece)Slide18

Origins of Myths

Myths are a way of organizing the contents of a human’s complex mind

Most are verbal, however, cave art that is 30,000 years old shows the use of myths

Cave art depicts at least 4 main concepts:1. Shamanic voyages (healers travelling the world)2. Hunting magic (showing large herds and vulnerable animals)

3. Myths or parables (instructing people on how to live the “proper” way4. Rites of passage (rituals and ceremonies that usher people into various stages of life) Slide19

Late Stone Age Culture

Used blades, spears, and arrows

Bows and arrows have been found that are approximately 20,000 years old

Hunted animals for their skins, not just foodAte plant foods in addition to some meatUsed Ostrich-eggshell beads, painted animals on rocks, and made clay sculpturesSlide20

The Spread of Homo sapiens

Physically and culturally modern human beings were the first to occupy the harsh climates of Asia

Siberian fossils are between 35,000 and 20,000 years old

Alaskan and Canadian fossils are between 15,000 and 12,000 years oldSlide21

Colonizing America

There is strong support that Native Americans are of Asian decent

This is done using blood group and tooth shape evidenceSlide22

Colonizing Austrailia

First colonized

Austrailia

60,000 to 40,000 years agoAustralia was linked to New GuineaMigrants still would have had to cross 30-90km of open waterThey may have been connected to the widespread extinction of grass eating marsupials in

Austrailia 40,000- 15,000 years agoSlide23