Fig. 18-0a

1. Animal diversity Fig. 18-0a

2. Colonial protists as ancestors of modern animals Fig. 18-2a Somatic cells Digestive cavity Reproductive cells Infolding Colonial protist, an aggregate of identical cells Hollow sphere of unspecial- ized cells Beginning of cell specialization Gastrula-like “proto-animal” 2 5 4 3 1

3. What makes an animal an animal? Internal digestion Fig. 18-5d Most sponges have no symmetry, but the Choanocyte shown here has radial symmetry

4. Evolution of multicellularity leading to the animal kingdom Choanoflagellate colonies Sponge coanocytes Single choanoflagellate Recent studies suggest that choanoflagellates are cousins to all animals in the same way that chimpanzees are cousins to humans. From left, a choanoflagellate colony, feeding cells (coanocytes) of sponges that resemble choanoflagellates and a choanoflagellate with its long flagellum and collar of filaments. There can be millions of choanoflagellates in a gallon of sea water. (Sean Carroll, New York Times, 12/13/2010)

5. Digestive tract and body cavity (coelom) Body covering (from ectoderm) Fig. 18-3b Coelom Tissue layer lining coelom and suspending internal organs (from mesoderm) Digestive tract (from endoderm) Complete gut

6. Symmetry – radial and bilateral Dorsal surface Top Fig. 18-3a Anterior end Posterior end Ventral surface Bottom

7. No true tissues Sponges Radial symmetry Cnidarians Ancestral colonial protist Echinoderms Fig. 18-4 Deuterostomes Chordates (humans) Eumetazoans True tissues Flatworms Bilaterians Bilateral symmetry Molluscs Protostomes Annelids Arthropods Body plans of animals helps reconstruct animal evolution Nematodes

8. Sperm Egg 1 Meiosis Key Fig. 18-1b-1 Haploid (n) Diploid (2n) Adult

9. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) Key Fig. 18-1b-2 Haploid (n) Diploid (2n) Adult

10. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) 3 Key Fig. 18-1b-3 Haploid (n) Diploid (2n) Eight-cell stage Adult

11. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) 3 Key Fig. 18-1b-4 Haploid (n) Diploid (2n) Eight-cell stage Adult 4 Blastula (cross section)

12. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) 3 Key Fig. 18-1b-5 Haploid (n) Diploid (2n) Eight-cell stage Adult 4 Blastula (cross section) 5 Early gastrula (cross section)

13. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) 3 Key Fig. 18-1b-6 Haploid (n) Diploid (2n) Eight-cell stage Adult 4 Blastula (cross section) Ectoderm 5 Early gastrula (cross section) Endoderm 6 Internal sac Future mesoderm Later gastrula (cross section)

14. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) 3 Key Fig. 18-1b-7 Haploid (n) Diploid (2n) Eight-cell stage Adult 4 Blastula (cross section) Digestive tract Ectoderm 5 Larva 7 Early gastrula (cross section) Endoderm 6 Internal sac Future mesoderm Later gastrula (cross section)

15. Sperm Egg 2 1 Meiosis Zygote (fertilized egg) 3 Key Fig. 18-1b-8 Haploid (n) Diploid (2n) Eight-cell stage Adult 8 Metamorphosis 4 Blastula (cross section) Digestive tract Ectoderm 5 Larva 7 Early gastrula (cross section) Endoderm 6 Internal sac Future mesoderm Later gastrula (cross section)

16. Tunicates Chordates Ancestral chordate Lancelets Hagfishes Brain Craniates Fig. 19-1 Lampreys Head Vertebrates Sharks, rays Vertebral column Ray-finned fishes Jawed vertebrates Jaws Lobe-fins Lungs or lung derivatives Amphibians Lobed fins Tetrapods Reptiles Legs Amniotes Amniotic egg Mammals Milk

17. Carboniferous Devonian Eusthenopteron Pandericthys Tiktaalik Fig. 19-4ab Tetrapod evolution from the fossile record Acanthostega Ichthyostega Tetrapod with no gills, limbs better-adapted for bearing weight Time known to exist 360 340 300 280 0 400 320 420 380 260 Millions of years ago

18. Carboniferous Devonian Fig. 19-4ac Modern amphibians Reptiles (including birds) and mammals Time known to exist 340 320 260 0 420 400 300 280 380 360 Millions of years ago

19. Fig. 19-6c

20. Wing claw (like dinosaur) Teeth (like dinosaur) Fig. 19-7a A bird is a feathered reptile able to fly Long tail with many vertebrae (like dinosaur) Feathers