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Human Evolution

Human Evolution. I. Darwin. " light will be thrown on the origin of man and his history ". from On the Origins of Species, 1859

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Human Evolution

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  1. Human Evolution

  2. I. Darwin • "light will be thrown on the origin of man and his history". from On the Origins of Species, 1859 • … the weighty arguments derived from the nature of the affinities which connect together whole groups of organisms- their geographical distribution in past and present times, and their geological succession. The homological structure, embryological development, and rudimentary organs of a species remain to be considered, whether it be man or any other animal, to which our attention may be directed; but these great classes of facts afford, as it appears to me, ample and conclusive evidence in favour of the principle of gradual evolution. The strong support derived from the other arguments should, however, always be kept before the mind. from The Descent of Man, 1871

  3. II. Why Study Human Evolution? 3-year-old Australopithecus afarensis Knees of a Biped, Shoulders of a climber Dinkenesh,” meaning “You are beautiful” or "you are wonderful"

  4. III. Phylogenetic Evidence Phylogeny based on anatomy Elongated skull, brow ridge enlarged shorter and stouter canines, front of upper jaw, fusion of certain bones in wrist, larger ovaries, mammaries, reduced hairiness Larger brains, no tail, more erect, hips/ankles more flexible, changes in structure of arms/ shoulder

  5. Molecular markers Antibody response Mitochondrial cytochrome oxidase II alleles

  6. Timing divergence from the molecular clock and fossils

  7. IV. Genetic and other differences Human chromosome 2 and its homologues in chimpanzees & gorillas

  8. Other data: 1.4% nucleotide subst., 3.4% in/del = 5%

  9. What makes a human? Differences in gene expression patterns in different tissues of humans, chimps, and rhesus macaques

  10. Enard et al., Science, 2002

  11. Stellar’s Jay Blue Jay

  12. Behavioral traits we inherited from Chimp-Human Common Ancestor • Knucklewalker (our ancestors, since divergence with chimps) • Broad fruit based diet • Lived in a range of habitats • Tools • Hunted • Dominated by Males/Females • Violent aggression/war? • Homosexuality, recreational sex? Differ between Chimps and Bonobos

  13. V. Fossil Evidence Hominin or hominid: species more closely related to human than chimp

  14. Lucy Human and Chimp

  15. "The Laetoli Footprints" Note position of big toe And heel strike Natl Geographic Soc. See also: http://www.pbs.org/wgbh/evolution/library/07/1/l_071_03.html

  16. Summary of fossil evidence on the recent ancestry of humans

  17. Phylogeny of Homo sapiens and recent ancestors and extinct relatives = H. erectus Very hypothetical Evidence for hominid radiation Paranthropus boisei, left and Homo ergaster both lived in what is now Koobi Fora, Kenya, about 1.7 million years ago.

  18. VI. Origin of Species Homo sapiens Oldest fossils of ergaster/erectus appear simultaneously in Africa,Europe and Asia about 1.6-1.9 mya, all ancestors > 2mya from Africa

  19. Genetic Evidence: Genetic (mtDNA) diversity in humans versus African great apes Single origin? All pairwise differences between individuals within a species

  20. Evidence of geographic structure in living human populations Multiorigin?

  21. Phylogeny of Neandertals & modern humans (mtDNA) Single origin?

  22. An evolutionary tree of complete mitochondrial DNAs of 53 humans Single origin?

  23. Phylogenetic tree for 14 human populations based on allele frequencies at 30 microsatellite loci Single origin < 300,000 ya

  24. Genetic diversity at a single locus among people of 7 geographic regions Single origin < 300,000 ya

  25. VII. Human Attributes Making complex tools

  26. Thumb metacarpal bones in a variety of hominins

  27. Language? Neandertal Chimp Brain Body Mass Hyoid bones from Homo neanderthalensis and a common chimpanzee H. habilis, H. ergaster/erectus, and H. sapiens • afarensis, A. africanus, • P. boisei, and P. robustus; bonobo, common chimpanzee, orangutan, and gorilla

  28. VIII. Summary • Relationships among Humans and Extant Apes • Divergence time about 5 mya • Hominid radiation • African Replacement or independent evolution of • H. sapiens in Africa, Europe and Asia? • 5. Evolution of uniquely human traits

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