Vertebrates Hagfish, Lampreys Cartilagenous Fish Bony Fish Amphibians Mammals Birds Reptiles Skull Backbone Paired Fins Jaws Bony Skeleton Swim Bladder Four Limbs Terrestrial Phase Amniotic Egg Endothermy Hair Mammary Glands

Mammals Hair, mammary glands Most advanced nervous system Learning important to survival Warm blooded Humans are mammals

Humans are primate mammals Class Mammalia –Order Primates Prosimians (e.g. lemurs) Tarsiers Anthropoids (e.g. monkeys, hominoids)

Tarsier Macaque Lemur

Primates : Humble Beginning Primates Shrew Rabbit Shrew-like Ancestor

Major Primate Groups Lemurs Tarsiiformes New World Monkeys Old World Monkeys Gibbons Orangutan Gorilla Chimp Human Family Hominidae Hominoidea : Apes and Humans Hominidea : Great Apes and Humans Homininae : African Great Apes and Humans

What Features Are Associated With Primate Evolution? I. Sensory Adaptations –Protected, forward looking eyes with stereoscopic vision –Improved sight : more detail even in low light –Reduction of olfactory structures

II. Adaptations for tree-climbing and insectivory –Freely moving limbs and digits –Long mobile digits capable of grasping –Retention of tail as organ of balance –Evolution of upright body posture and extensive head rotation –Increased body size –Evolution of nervous system to give precise and rapid control of movement What Features Are Associated With Primate Evolution?

Major Primate Groups Lemurs Tarsiiformes New World Monkeys Old World Monkeys Gibbons Orangutan Gorilla Chimp Human Family Hominidae 25 mya 12 mya 6 mya Hasegawa et al mya 38 mya Estimated Divergence Times

What Traits Do Humans and Apes Share? Larger Brain Absence of a tail More erect posture Greater flexibility of hips, ankles, wrist, thumb DNA sequence similarity

Gorilla Chimpanzee Human Horai et al (1995) Proc. Nat Acad Sci. 92: Mito DNA (complete sequences) Kim and Takenaka (1996) A. J. Phys. Anth. 100: Y-chromosome DNA Ruvolo (1997) Mol Biol Evol 10: Examined 14 different DNA data sets Satta et al (2000) Mol. Phyl. Evol 14: Autosomal DNA (45 genes, 47,000 bp of DNA) Paabo (2003) Nature 421: Review of human and chimp/ape genomes.

Common Ancestor of Chimp/Human Knuckle-walker? Broad-fruit based diet May have hunted May have used tools May have had complex social relationships: (e.g.warfare, cannabalism, sharing, teaching, compassion)

Our Understanding of Human Evolution is Primarily Based on Fossils