1. Vertebrates Hagfish Lampreys Sharks Bony fish Land vertebrates Coelacanth Many groups known only from fossils Cladogram of vertebrates, stressing early forms from UC Berkeley Museum of Paleontology

2. Vertebrate characters Cranium – brain case Vertebrae (spinal protection of cartilage or bone) – almost all *agility *speed No larval stages Evolved during Cambrian (early Paleozoic) Myllokunmingia fossil from SE China, -530 my

3. Trends in vertebrate evolution improvements in vertebral column – cartilage, bone gill slit supports – jaws, other head bones appendages – fins, legs, wings respiration – gills & lungs circulation – heart reproduction – eggs, shells, “live” young existing (& some extinct) classes trace some of the most important advances along the vertebrate evolutionary path – next slides follow these

4. No Jaws Hagfish *cartilage *partial cranium *slime a defense mechanism Lampreys *cartilage *full cranium *fish parasites & free living hagfish tie themselves into knots to clean themselves

5. Jaws Carcharodon megalodon Miocene (Cenozoic) shark recent Swedish shark evolved from gill arches later bore teeth mid Paleozoic (Silurian) origin Dunkleosteus Devonian (mid Paleozoic) Placoderm

6. Jaws II

7. Jaws III also: *articulated cranium & spine *appendages (fins) - some paired modern day Cartilaginous Fish *sharks, rays, etc. *no swim bladder – must swim to “levitate” Manta Ray 1 m

8. Bone Bony fish = ray-finned fish *also bony scales *most numerous & diverse vertebrate *lungfish have “lungs” gut pockets modified circulation

9. Legs Amphibians *the mosses of the animal world *limbs supported by bones support movement *articulated to “girdles” connections to spines hips and shoulder *but amphibians tied to water: at least eggs (shell-less) & larval stages young Rough-skinned Newt

10. Legs II more on Amphibians *land life advantages more oxygen prey – arthropods & plants fewer (no?) predators *sound / sight / balance improvements (terrestrial sensors) ears and eyes *first amphibians: Devonian (mid Paleozoic) Northwest Tailed Frog

11. Shelled eggs Reptiles *amniote eggs with: extra-embryonic membranes shells for protection *dry scaly skin *internal fertilization *adult care for young *kidneys conserve water

12. Reptiles II Evolved in late Paleozoic (Carboniferous) Huge diversity – polyphyletic with many long-lived lines from the end of the Paleozoic Two early lines *Sauropsids – most of the diverse lines *Synapsids – ultimately gave rise to mammals

13. Birds Just another reptilian group? Feathers – insulating, flight (modified scales) Bones hollow Beaks Thermoregulation – high metabolism rates All adaptations for flight Patterns of behavior *Elaborate mating behavior *Maternal/paternal care *Migration

14. Birds II Evolved from theropod dinosaurs, mid Mesozoic Archaeopteryx lithographica 150 my

15. Birds III Sinosauropteryx prima 125 my Caudipteryx zoui 125 my

16. Mammals I Hair (modified scales) Milk fed to young Live young (except for 3 that lay eggs) Precise teeth that fit together 3 middle ear bones (derived from jaw bones)

17. Mammals II Three major lines *monotremes – egg layers *marsupials – pouched *eutherian – placental Spiny echidna, egg-layer Marsupial “mouse” Blue whale, largest mammal

18. Mammals IIIA Evolved in early Paleozoic 200 mya Adaptive radiation during mesozoic & cenozoic tied to continental drift – see ST Fig 26.2 *End of mesozoic opened habitats *Mammals much more efficient terrestrial forms Drifting continents isolated mammalian groups on “rafts”

19. Mammals IIIB Compare with ST Fig 26.2 Early Triassic Late Triassic Early Cretaceous Late Cretaceous *

20. Mammals IIIC Modern day mammalian distribution

21. Mammals IV - Primates 3 present groups *prosimians – lemurs, galagos *tarsiers *monkeys, apes, humans Early primates evolved in early Cenozoic from rodent ancestors 5 features preadapted early primates to modify later in the line toward humans *enhanced vision *upright walking *modifications in hand bones & muscles *generalized teeth *social behavior (& increases in brain capacity and complexity) Barbary Macaque Tarsier Galago

22. Human evolution Humans evolved in Africa Earliest huminoids – mid Cenozoic (25 mya) *cooler climate led to challenges *later radiation of “southern apes” (Australopithecus) 4-3 mya *first appearance of Homo ~ 2.5 mya Homo erectus leaves Africa ~2 mya Homo sapiens evolved 150,000 ya Homo neanderthalensis evolved 250,000 ya; extinct 35,000 Recent studies show no DNA mixing or carryover of H. n. DNA in modern human lines Most evidence supports Out of Africa theory rather than multiregionalism Best site for current status of human evolution facts: http://www.talkorigins.org/faqs/homs/

23. Human evolution timeline Chart from: http://www.talkorigins.org/faqs/homs/species.html Interactive Human Evolutionhttp://www.talkorigins.org/faqs/homs/species.htmlInteractive Human Evolution