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Fig. 18-0a Animal diversity. Fig. 18-2a 1 2 3 4 5 Colonial protist, an aggregate of identical cells Hollow sphere of unspecial- ized cells Reproductive.

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Presentation on theme: "Fig. 18-0a Animal diversity. Fig. 18-2a 1 2 3 4 5 Colonial protist, an aggregate of identical cells Hollow sphere of unspecial- ized cells Reproductive."— Presentation transcript:

1 Fig. 18-0a Animal diversity

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

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

4 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) Evolution of multicellularity leading to the animal kingdom Choanoflagellate colonies Sponge coanocytes Single choanoflagellate

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

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

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

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

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

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

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

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

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

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

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

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

17 Fig. 19-4ab Devonian Carboniferous Time known to exist Eusthenopteron Pandericthys Tiktaalik Acanthostega Ichthyostega Tetrapod with no gills, limbs better-adapted for bearing weight Millions of years ago Tetrapod evolution from the fossile record

18 Fig. 19-4ac Devonian Carboniferous Millions of years ago Modern amphibians Reptiles (including birds) and mammals Time known to exist

19 Fig. 19-6c

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


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