Human Evolution

• Primates


  • Small group of mammals that have large brains relative to body size, forward-directed eyes, flexible hands and feet, and arms that can rotate fully
  • Most primates have tails
• Hominid


  • Any human-like species, including us
  • Bipedal (walks on two legs)
  • Intelligent (large brain, uses tools)
• Hominids are not the same as modern apes
• Modern apes


  • Not bipedal
  • Do not have a large brain case compared to humans
  • Do not make tools
• Chimpanzees are our closest relative - our DNA is 98% similar to theirs
• Primate evolutionary tree


  • Prosimians (ex. Lemurs, Lorises, Tarsiers)
  • Anthropoid
  • Monkeys
  • Hominoids (or apes)
• Detailed genetic analysis has confirmed that chimpanzees are our closest living relatives
• We share 98.8% of our DNA with chimpanzees
• Humans and chimpanzees both differ from gorilla DNA by 1.6%
• Hominids


  The modern human forms a clade of many different species, including our direct ancestors
• Major events in hominid fossil record

  1. 6-7 million years ago - Sahelanthropus was beginning to occasionally walk upright

  2. 3.4 million years ago - Australopithecus afarensis, showed use of stone tools

  3. 2 million years ago – Homo gautengensis and Homo habilis evolved (were called the handy man – making stone axes and cutting tools)

  4. 790 000 years ago – use of hearths for cooking

  5. 800 000-200 000 – hominid brain size increased rapidly, and gave rise to both Homo heidelbergensis and Homo neanderthalensis

  6. 100 000 years ago – the first modern Homo sapiens evolved in East Africa
• Homo sapiens


  • Anatomically modern humans
  • Oldest fossils found so far are perhaps 195,000 years old
  • Found in Africa (also in Ethiopia)
• All early hominids evolved and lived in Africa
• Hominid migration out of Africa

  1. Homo erectus about 1.9 million years ago - first species to leave Africa, populated Eurasia and survived until 100 000 years ago

  2. Homo neanderthalensis left Africa 500 000 – 300 000 years ago and populated parts of Europe
• Scientists have been able to extract DNA from Neanderthal bones, and sequence their entire genome
• Geneticists then compared the DNA to modern humans and discovered that some humans of Asian and European descent have small sequences of Neanderthal genomes
• This provides evidence that some interbreeding may have occurred when early Homo sapiens made contact with Neanderthals
• Scientists have been linking the above discovery to why some people have more severe covid-19 symptoms than others