Copyright © 2005 Pearson Prentice Hall, Inc. Animal Diversity I: Invertebrates

Copyright © 2005 Pearson Prentice Hall, Inc. Animal Key Features

Copyright © 2005 Pearson Prentice Hall, Inc. Anatomical Branch Points on the Animal Evolutionary Tree An evolutionary tree of some major animal phyla (F22.1 p. 424)

protostomes bilateral deuterostomes lophotrochozoansecdysozoans Porifera (sponges) Cnidaria (jellyfish, corals, anemones) Ctenophora (comb jellies) Arthropoda (insects, arachnids, crustaceans) Platyhelminthes (flatworms) Annelida (segmented worms) Mollusca (clams, snails, octopods) Echinodermata (sea stars, sea urchins) Chordata (lancelets, vertebrates) cuticle molted protostome developmentdeuterostome development bilateral symmetry radial symmetry no tissuestissues Nematoda (roundworms) Sponges: Lack Tissues Radial or Bilateral Symmetry

Radial symmetry central axis plane of symmetry Bilateral symmetry anterior plane of symmetry posterior Animals with Tissues Exhibit Either Radial or Bilateral Symmetry Body symmetry and cephalization (F22.2 p. 425) Anatomical Branch Points on the Animal Evolutionary Tree

Copyright © 2005 Pearson Prentice Hall, Inc. Anatomical Branch Points on the Animal Evolutionary Tree –Embryonic Tissue Layers Radially Symmetrical Animals Have Two Bilaterally Symmetrical Animals Have Three –Bilateral Animals Have Heads –Most Bilateral Animals Have Body Cavities –Body Cavity Structure Varies Among Phyla Body cavities (F22.3 p. 426)

“True” coelom (annelids, chordates) body wall coelom digestive tract digestive cavity } } “False” or pseudocoelom (roundworms) body wall pseudocoelom digestive tract digestive cavity } No coelom (cnidarians, flatworms) body wall digestive tract digestive cavity } Body cavities (F22.3 p. 426) Anatomical Branch Points on the Animal Evolutionary Tree

Copyright © 2005 Pearson Prentice Hall, Inc. Anatomical Branch Points on the Animal Evolutionary Tree Simpler Body Cavities Evolved from Coelomate Body Plans Bilateral Organisms Develop in One of Two Ways –ProtostomesDeuterostomes Protostomes: Two Distinct Evolutionary Lines –EcdysozoansLophotrochozoans

Comparison of the Major Animal Phyla (T22.1 p. 428)

epithelial cell spicules amoeboid cell pore cell collar cell (water flow) pore osculum Major Animal Phyla Sponges: Simple Body Plan (F22.4 p. 428)

Sponge diversity (F22.5 p. 429)

Copyright © 2005 Pearson Prentice Hall, Inc. Cnidarians: Well-Armed Predators –Cnidarian diversity (F22.6 p. 430) –Polyp and medusa (F22.7 p. 431) –Cnidarian weaponry: the cnidocyte (F22.8 p. 431) Major Animal Phyla

Major Animal Phyla Cnidarians: Well- Armed Predators Cnidarian diversity (F22.6 p. 430)

Polyp mouth lining of gastrovascular cavity tentacle gastrovascular cavity column foot body wall mesoglea Medusalining of gastrovascular cavity gastrovascular cavity tentacle mouth mesoglea body wall Major Animal Phyla Polyp and medusa (F22.7 p. 431)

nuclei trigger filament Cnidarian weaponry: the cnidocyte (F22.8 p. 431)

Copyright © 2005 Pearson Prentice Hall, Inc. Major Animal Phyla Flatworms –Organs –Lack Respiratory & Circulatory Systems –Flatworm organ systems (F22.9 p. 432) –The life cycle of the human pork tapeworm (F22.10 p. 433)

nerve cord excretory pore brain Excretory system Nervous system excretory canal Digestive system eyespots gastrovascular cavity pharynx (with mouth at tip) Major Animal Phyla Flatworm organ systems (F22.9 p. 432)

Major Animal Phyla – Life cycle of human pork tapeworm (F22.10 p. 433)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? Annelids Are Composed of Identical Segments –Figure An annelid, the earthworm (p. 434) –Figure Diverse annelids (p. 435)

coelom intestine nephridia excretory pore ventral nerve cord anus coelom brain mouth pharynx ventral vessel ventral nerve cord hearts esophagus cropgizzard intestine

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? Most Mollusks Have Shells –Figure A generalized mollusk (p. 435) – Gastropods Are One-Footed Crawlers Figure The diversity of gastropod mollusks (p. 436)

digestive tract gonad heart coelom shell mantle anus gill nerve cords foot mouth radula eye tentacle ganglia (brain)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? – Bivalves Are Filter Feeders Figure The diversity of bivalve mollusks (p. 436)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? – Cephalopods Are Marine Predators Figure The diversity of cephalopod mollusks (p. 437)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? Arthropods Are the Dominant Animals on Earth –Figure The exoskeleton allows precise movements (p. 438) –Figure The exoskeleton must be molted periodically (p. 438) –Figure Segments are fused and specialized in insects (p. 438) –Figure Arthropods possess compound eyes (p. 439)

abdomen wing thorax head antennae compound eye mouth parts

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? – Insects Are the Only Flying Invertebrates Figure The diversity of insects (p. 439)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? – Most Arachnids Are Predatory Meat Eaters Figure The diversity of arachnids (p. 440)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? – Myriapods Have Many Legs Figure The diversity of myriapods (p. 441)

(a)(b)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? – Most Crustaceans Are Aquatic Figure The diversity of crustaceans (p. 441)

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? Roundworms Are Abundant and Mostly Tiny –Figure A freshwater nematode (p. 442) –Figure Some parasitic nematodes (p. 443)

ovary vagina eggs mouth cuticle posterior end anterior end intestine

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? Echinoderms Have a Calcium Carbonate Skeleton –Figure The diversity of echinoderms (p. 443) –Figure The water-vascular system of echinoderms (p. 444)

ampulla tube feet sieve plate canals plates of endoskeleton

Copyright © 2005 Pearson Prentice Hall, Inc What Are the Major Animal Phyla? The Chordates Include the Vertebrates