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HUMAN EVOLUTION. SBI3U. Why are humans so successful?. 3 Physical Characteristics 1. very large brain to body ratio 2. hands are capable of fine manipulation and coordination 3. walk upright (bipedal), hands are free to use tools
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HUMAN EVOLUTION SBI3U
Why are humans so successful? 3 Physical Characteristics 1. very large brain to body ratio 2. hands are capable of fine manipulation and coordination 3. walk upright (bipedal), hands are free to use tools Ability to perform complex reasoning, exceptional ability to learn, make use of sophisticated tools and communicate using complex language.
Hominids Hominoids
Misconceptions • Humans did not evolve FROM apes • Rather, we share a COMMON ANCESTOR
Humans closest living relative • Humans and chimpanzees share 98.8% of their DNA • The most recent common ancestor we share with chimps lived in Africa more than 6 million years ago
Hominids • Hominids are all species descended from the most recent common ancestor of chimpanzees and humans that are on the human side of the lineage
The Hominid Fossil Record • The sequence of steps in the evolution of humans
The Hominid Fossil Record • Between 6 and 7 million years ago a human ancestor was walking upright occasionally • First evidence of stone tool use by Australopithecus afarensis date to 3.4 million years ago • The first members of our own genus, Homo habilisevolved 2 million years ago • Homo habilis, the handy man, built stone axes and large cutting tools • Hunting tools allowed hominids to increase the amount of meat in their diet, providing a rich source of protein and fat • By this time, hominid brains were significantly larger than the chimpanzee-sized brains of australopithecines
The Hominid Fossil Record • Hominid brain size increased relatively rapidly from about 800 000 years ago to 200 000 years ago • Homo neanderthalensisand Homo sapiens evolved during this time • The first modern humans had evolved by about 100 000 years ago in East Africa
Out of Africa • All early hominids evolved and lived in Africa • The first species to spread beyond Africa was Homo erectus, about 1.9 million years ago, and survived throughout Eurasia until at least 100 000 years ago • 500 000 to 300 000 years ago Homo neanderthalensisleft Africa and populated parts of Europe • After the earliest humans evolved they began to spread out of Africa into Eurasia and eventually reached the Americas
Cultural Evolution • Humans and chimpanzees are so similar genetically, but are dramatically different culturally • Human culture is so rich and diverse: • Over 6000 languages • Countless artistic endeavors in music, dance and fine arts • Admire and cherish the talents of others • Societies have different rituals, customs and beliefs
Cultural Evolution • Our ancestors lived as hunter-gatherers for 300 000 generations • In the last 1000 generations or less humans have domesticated plants and animals, developed agriculture and begun to live in large population centres • Only during the last 10 generations has our population skyrocketed
Human Races • Genetic comparisons conclusively show that, from a biological perspective, ‘races’ do not exist • Traits we associate with races, mostly skin colour, are visibly obvious but genetically minimal. • More diversity within ‘races’ than there is between ‘races’