Animal Body Plans

1. Animal Body Plans Chapter 32

2. Criteria for Evolutionary Development & Classification Cellular organization Symmetry Coelom Digestive system Segmentation Cephalization

3. Kingdom Animalia • Symmetry • Unorganized • Radial • Bilateral • Cellular organization • Tissues, organs, systems

4. Kingdom Animalia coelom digestive tube • Coelom • Body cavity or not • Digestive system • None, 1 or 2 openings, how

5. Kingdom Animalia • Segmentation • Repetition of body parts • Cephalization • Development of a “head end”

6. Geologic Time Scale Millions of Years end of dinosaurs 1st dinosaur 1st reptiles 1st amphibians 1st land plants 1st fish 1st invertebrates

7. Ediacaran Fauna: distinctive group of fossils dating from and existing only during Precambrian time • The fauna arose about 600 mya. • Named for Australia's Ediacara hills, where it was first discovered. Such fossils were later found to be widespread. • These animals lived in shallow seas and had soft bodies that bear little resemblance to later life forms, and were about 1 m in length. • May be an evolutionary dead end

8. Reconstruction of the sea floor during the Vendian times when the Ediacaran organisms thrived

9. Ediacaran Fauna(600-540 MYBP)end of Precambrian era

10. Edicarian Fauna

11. Ancient Seas at the During the Cambrian Radiation (540 MYBP) Burgess Shale

12. Ancient Seas at the During the Cambrian Radiation(540 MYBP) Drawings based on fossils collected from Burgess Shale in British Columbia, Canada

13. Burgess Shale Fauna(540 MYBP) Feeding tentacles Hallucigena spines Similar to a sea urchin An explosion of body plans

14. Burgess Shale Fauna(540 MYBP) Pikaia- earliest known chordate

15. Anomalocaris Burgess Shale Fauna(540-530 MYBP Opabinia Wiwaxia

16. Living Invertebrates

17. Phylogentic Relationships of Animals Platyhelminthes Porifera Mollusca Chordata Arthropoda Annelida Cnideria Nematoda Echinodermata pseudocoelom segmentation acoelom Protostome: schizocoelem Deuterostomes: eucoelom radial symmetry bilateral symmetry no true tissues true tissue Ancestral Protist

18. Early Embryonic Development of an Animal

19. Major Stages of Animal Development • gametogenesis • fertilization • cleavage • blastula • gastrulation • differentiation and morphogenesis

20. Hypothetical Scheme for the Origin of Multicellularity in Animals

21. Protostome vs Deuterostome Fig. 32-9a Cleavage Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderms, chordates) Eight-cell stage Eight-cell stage Spiral and determinate Radial and indeterminate

22. Protostome vs Deuterostome Coelom formation Fig. 32-9b Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderms, chordates) Coelom Key Ectoderm Archenteron Mesoderm Endoderm Coelom Blastopore Mesoderm Blastopore Mesoderm Solid masses of mesoderm split and form coelom. Folds of archenteron form coelom.

23. Protostome vs Deuterostome Fate of Blastopore Fig. 32-9c Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderms, chordates) (c) Fate of the blastopore Anus Mouth Key Ectoderm Digestive tube Mesoderm Endoderm Anus Mouth Mouth develops from blastopore. Anus develops from blastopore.

24. What is a Phylum?

25. Some Examples of Animal Phyla • Phylum Cnidaria • sea anemones, corals, jellyfish, man-of-wars & hydroids • Phylum Mollusca • snails, slugs, chitons, clams, oysters, octopods & squids • Phylum Arthropoda • spiders, scorpions, crabs, shrimp, insects & centipedes • Phylum Echinodermata • sea stars, sea urchins, sea cucumbers & sea lilies • Phylum Chordata • sea squirts, fish, amphibian, reptiles, birds & mammals

26. Phylum Chordata

27. Major Body Plan Characteristics of Animals • Symmetry • Primary Germ Layers • Gut Organization • Body Cavity • Segmentation • Skeletal Systems • Circulatory Systems • Appendages • Coloniality

28. Symmetry • Asymmetry • Radial Symmetry • Bilateral Symmetry

29. Symmetry Bilateral Symmetry Radial Symmetry

30. Radial Symmetry JellyfishPhylum Cnidaria

31. Pentamerous Radial Symmetry Sea StarsPhylum Echinodermata

32. Bilateral Symmetry SlugPhylum Mollusca

33. Bilateral Symmetry SquidPhylum Mollusca

34. Primary Germ Layers • None • Diploblastic • Triploblast

35. Fates of the Primary Germ Layers • Ectoderm • hair, nails, epidermis, brain, nerves • Mesoderm • notochord (in chordates), dermis, blood vessels, heart, bones, cartilage, muscle • Endoderm • internal lining of the gut and respiratory pathways, liver, pancreas

36. The Formation of Primary Germ Layers

37. The Formation of Primary Germ Layers

38. Ectoderm gut Endoderm Diploblastic

39. Diploblastic- two germ layers Phylum Cnidaria

40. Ectoderm Mesoderm gut Endoderm Triploblastic

41. Body Cavities • Acoelomate • Eucoelomate • Pseudocoelomate

42. Acoelomate Body covering (from ectoderm) Tissue- filled region (from mesoderm) Wall of digestive cavity (from endoderm) (c) Acoelomate

43. Pseudocoelomate Body covering (from ectoderm) Pseudocoelom Muscle layer (from mesoderm) Digestive tract (from endoderm)

44. Eucoelomate Coelom Body covering (from ectoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) Digestive tract (from endoderm)

45. Advantages of aFluid-Filled Body Cavity • hydrostatic skeleton • greater freedom for internal organs • greater body size because of body fluid circulation

46. Gut Organization • No Gut • Blind Sac Gut • Complete Gut

47. No Gut SpongesPhylum Porifera

48. No Gut SpongesPhylum Porifera

49. Blind Sac Gut Phylum Cnidaria

50. Complete Gut