Theory of Human Evolution

1. Theory of Human Evolution

2. What makes us Human? • Three distinct physical characteristics: • Large brain relative to body size • Used for reasoning and communication • Bipedal • Hand and opposable thumbs capable of fine manipulation • However, many other animals have evolved some or all of these traits. What makes us unique is the degree to which these traits have evolved

3. Human Phylogeny • Homo sapiens (humans) are members of the primate group • Humans and Chimps share 98.8% of our DNA • Primates are characterized by: • Large brains (relative to body) • Forward directed eyes • Flexible hands/feet • Arms that can rotate fully

4. Out of Africa Theory All early hominids lived and began to evolve in Africa Fossils record the history and distribution of our ancestors The first species to leave Africa was Homo erectus about 1.9 million years ago

5. Scientists have been able to sequence the Neanderthals genome, and have discovered small sequences are shared with humans of Asian and European descent This suggests interbreeding may have occurred between early Homo sapiens and Neanderthals

6. Cultural Evolution • Culture and language have given humans the advantages to evolve into what we are today • The very rapid changes in culture over the past 10,000 years has actually sped up human evolution • Our ancestors lived as hunter gatherers until the domestication of plants and animals • This lead to living in larger populations and a need to develop a common language and set of cultural norms • FoxP2 gene  codes for a protein that regulates a number of other genes and is vital for human speech • Scientists have found a version of this gene in all mammals • The human version of FoxP2 differs from the Chimpanzee gene in just 2 base pairs

7. Human Races From a biological perspective, “races” do not exist Traits associated with race, usually skin colour, are genetically minimal There is far more genetic diversity with-in so called “races” than there are between Therefore, race is a cultural classification, not biological

8. Sahelanthopus tchadensis 7 – 6 million years ago in Western Africa One of the earliest human ancestors we know of Had a chimpanzee sized brain Could be bipedal Smaller canines, similar to humans

9. Ardipithicus ramidus Approx. 4.4 million years ago Eastern Africa Species walked upright, but opposable big toes helped with tree climbing Dental analysis shows there was little size difference between males and females

10. Australopithecus afarensis Lucy 3.85 to 2.95 million years ago Eastern Africa Bipedal with arched feet and had canine teeth more like humans than chimps, however she had apelike body proportions and brain size

11. Australopithecus africanus • 3.3 – 2.1 million years ago • Southern Africa • Bipedal with arched feet • Mostly vegetarian still • Evidence suggests that they used tools (sharpened rocks) • Tool use emerged around 2.6 million years ago

12. Homo habilis 2.4 – 1.4 million years ago Eastern and Southern Africa Was given the name Homo habilis which means “handy-man” because at the time of discovery, they were thought to be the earliest tool users Brain size increased in size from ancestors typical 400 cm³ to 600 cm³

13. Homo erectus 1.89 million to 143,000 years ago North, East and Southern Africa and Western and Eastern Asia Was the first species known to make hearths Ate significant amounts of animal meat First species to be known for caring for their weak and old Longest lived species in our family tree

14. Homo heidelbergensis 700,000 to 200,000 years ago Europe and possibly in parts of Asia and Africa First early humans to venture into the cold regions of Europe First species to build shelters and hunt large animals with wooden spears and used other tools The first species to have evidence of burying their dead Approximately the same size as humans today Direct ancestors to the Neanderthals

15. Homo neanderthalensis 200,000 to 28,000 years ago Europe and Southwestern to Central Asia Closest extinct human ancestor Some defining facial features included; extremely large noses, angled cheek bones and larger skulls Shorter limbs to aid in heat conservation, and slightly smaller than humans (males – 5’5”, females – 5’1”) First to have evidence of wearing clothes May have been the first to communicate with language, and there is evidence of rituals and symbolism Used complex tools and hunting strategies

16. Homo floresiensis 95,000 to 17,000 years ago Indonesia Most recently extinct member of the Homo species Smallest species, with a brain about 1/3 the size of ours, nicknamed the “hobbit” Scientists hypothesize that they were dwarfed due lack of resources on the island

17. Homo sapiens 200,000 years ago to present Evolved in Africa, but now worldwide Fossil evidence shows that humans began to migrate out of Africa at least 100,000 years ago Last living species of our once diverse hominid family

18. Smithsonian interactive timeline on human evolution http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive http://www.youtube.com/watch?v=IWwYXJZvmjw http://www.youtube.com/watch?v=cZxCn7YgYJ8