My first lecture on the second year Bio263 module on human evolution. An overview of human evolution and palaeoanthropology. Taxonomy and humanity's place in nature. Who is our closest living relative? Evidence from morphology and molecules. See also Slidecast on YouTube http://www.youtube.com/watch?v=28bLQIGRbWU

3. Human Evolution sources of data Anatomically modern humans Homo neanderthalensis Ancient DNA Morphology Fossil Record Morphology Molecular phylogenetic & genomic studies Morphology Extinct hominins Living primates Population genetics studies with mtDNA, Y-chromosome & autosomal genes Homo sapiens

7. What people used to think in the 1960s Zallinger The March of Progress Pliopithecus - Proconsul - Dryopithecus - Oreopithecus – Ramapithecus - Australopithecus africanus - Australopithecus robustus - Australopithecus boisei - Homo habilis - Homo erectus - Early Homo sapiens - Neanderthal Man - Cro-Magnon Man - Modern Man

9. Human lineage thought to have diverged from African apes 15-28 Ma

10. A misreading of Darwin…

12. But who is our closest relative among living primates?

15. The Cladistics Revolution

16. All taxa to be monophyletic birds crocodilians tortoises turtles lizards snakes tuatara mammals amphibians archosaurs diapsids amniotes sauropsids tetrapods Amniotes are a monophyletic group Reptiles are a paraphyletic group Warm-blooded animals are a polyphyletic group

17. A taxonomic adjustment

18. A recent split! Vincent M. Sarich and Allan C. Wilson "Immunological time scale for hominid evolution" Science 158, 1967, p. 1200-1203. "that if, man and Old World monkeys shared a common ancestor 30 million years ago, then man and apes shared a common ancestor no more than 5 million years ago” this challenge to paleontological opinion purely on the basis of biochemistry of living species was initially either ridiculed or ignored.

21. Sequence-based phylogenies DNA sequence data… Make a tree Polymorphic sites

23. The trichotomy g c h

27. Resolving the trichotomy: DNA sequence data

28. Resolving the trichotomy: Morphology

29. Resolving the trichotomy: Morphology

30. Our cousins resolved g c h

31. Our cousins resolved

32. Another taxonomic adjustment Sub-tribe Hominina or “hominins” reserved for species on human lineage after divergence from chimps

33. But when and how…? Estimates of divergence time depend on models of genetic change (rate constant or variable) and on calibration points

35. But when and how…? Human/chimp divergence corrected for the difference in the mutation rate varies considerably across the genome. X-chromosome shows significantly lower divergence, compared to the rest of the genome. This may tell us something about the human/chimpanzee speciation (Patterson et al 2006 Nature) Human Chimp τ -speciation τ -gene divergence

36. Human/chimp speciation (Patterson et al 2006 Nature) The observed variation in human/chimpanzee divergence can be explained by a secondary hybridisation of the two species after the initial speciation event

38. http://www.greatapeproject.org

40. We are not 98% chimp! “ As most people know, chimpanzees share about 98% of our DNA, but bananas share about 50%, and we are not 98% chimp or 50% banana, we are entirely human and unique in that respect. It is simply a mistake to use an entirely human construct, which is rights, and apply it to an animal, which is not human. Rights come with responsibility and I have never seen a chimp fined for stealing a plate of bananas” Steve Jones

41. We are not 6 million years from a chimp! 6 million years

42. We are not 6 million years from a chimp! but 12 million years! http://www.sciencemag.org/ardipithecus/ Study of Ardipithecus ramidus (4.4Ma) suggest the last human-chimp ancestor was probably more human-like than chimp-like. “ Ar. ramidus lacks any characters typical of suspension, vertical climbing, or knuckle-walking. Ar. ramidus indicates that despite the genetic similarities of living humans and chimpanzees, the ancestor we last shared probably differed substantially from any extant African ape . Hominids and extant African apes have each become highly specialized through very different evolutionary pathways.” LCA