30.1 Evolutionary Trends Among Animals Domain Eukarya, kingdom Animalia Characteristics of Animals Heterotrophic, acquire food by ingestion Locomotion by means of muscles Multicellular, high degree of cell specialization Adult is diploid Reproduction usually sexual, with embryo undergoing developmental stages

Animal Diversity

30.1 Evolutionary Trends Among Animals Invertebrates Lack an endoskeleton of bone or cartilage All but one animal phylum are invertebrates Vertebrates Have an endoskeleton of bone or cartilage

Evolutionary Tree deuterostome development Chordates Deuterostomia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. common ancestor deuterostome development Chordates Deuterostomia Echinoderms bilateral symmetry 3 tissue layers body cavity molting of cuticle Arthropods Ecdysozoa tissue layers Roundworms Bilateria Annelids protostome development trochophore Protostomia multicellularity Molluscs ancestral protist Ttrochozoa Flatworms Rotifers Cnidarians Radiata radial symmetry 2 tissue layers Sponges

30.1 Evolutionary Trends Among Animals Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. dorsal posterior ventral anterior radial symmetry bilateral symmetry Type of Symmetry Asymmetrical No particular symmetry Radial Symmetry Circular organization, can be bisected in any plane to produce mirror images, some sessile Bilateral Symmetry Definite right and left halves; only a cut down the midline will produce mirror images, accompanied by cephalization

30.1 Evolutionary Trends Among Animals Level of Organization Cellular No true tissues; sponges Tissue Have ectoderm and endoderm; cnidarians like hydra Organ Have ectoderm, endoderm, and mesoderm; majority of animals

30.1 Evolutionary Trends Among Animals Embryonic development Animals with three tissues layers are either Protostomes( mouth first) or deuterstomes (anus first)differentiated by three major events: Cleavage Fate of blastopore Coelom formation Deuterstomes – echinoderms and chorodates Protostomes Ecdysozoa – roundworms and arthropods Trochozoa – have trochophore larvae

splitting of the mesoderm. outpocketing of primitive gut. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protostomes Deuterostomes Cleavage top view side view top view side view Cleavage is spiral and determinate. Cleavage is radial and indeterminate. Protostomes Deuterostomes blastopore mouth blastopore anus Fate of blastopore primitive gut anus primitive gut mouth Blastopore becomes mouth. Blastopore becomes the anus. Protostomes Deuterostomes mesoderm mesoderm Coelom formation gut gut Coelom forms by a splitting of the mesoderm. Coelom forms by an outpocketing of primitive gut.

30.2 Introducing the Invertebrates Sponges: Phylum Porifera Saclike body with many pores Multicellular, but lack organized tissues Filter feeders Asexual and Sexual Reproduction Asexually by budding, fragmentation or gemmule formation Hermaphroditic, usually not self-fertilizing Choanocytes (collar cells)-trap food particles trap food particles Classified on the basis of their skeleton Spicules, spongin

Simple Sponge Anatomy a. Yellow tube spoge,Aplysina fistularis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. Yellow tube spoge,Aplysina fistularis © Andrew J. Martinez/Photo Researchers, Inc

Simple Sponge Anatomy osculum sponge wall H2O out spicule pore H2O in Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. osculum sponge wall H2O out spicule pore H2O in through pores amoebocyte epidermal cell c. central cavity collar nucleus amoebocyte flagellum b. Sponge organization d. collar cell (choanocyte) 11

Simple Sponge Anatomy 12 osculum sponge wall H2O out spicule pore Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. osculum sponge wall H2O out spicule pore H2O in through pores amoebocyte epidermal cell c. central cavity collar nucleus amoebocyte flagellum a. Yellow tube spoge,Aplysina fistularis b. Sponge organization d. collar cell (choanocyte) a: © Andrew J. Martinez/Photo Researchers, Inc 12

Figure 15.4: Animated! (A) Body plan of a glass sponge. Arrows indicate direction of water flow. (B) Natural bath sponge. Fig. 15-4b, p. 296

Basket Sponge

Luffa sponge

30.2 Introducing the Invertebrates Cnidarians: Phylum Cnidaria True Tissues with two germ layers Tubular or bell-shaped animals with radial symmetry All aquatic, mostly marine Named for cnidocytes Contains nematocyst used in prey capture Body is two layered sac with gastrovascular cavity Two basic body forms – polyp and medusa Includes corals, jellyfish, and hydrozoans Corals - polyps Jellyfish - medusae Hydrozoans - may have both forms

Cnidarian Diversity a. mouth tentacle gastro- vascular cavity planula Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. mouth tentacle gastro- vascular cavity planula mesoglea zygote Polyp asexual budding fertilization mesoglea gastrovascular cavity sperm egg mouth a. tentacle Medusa

Fig. 30.5b b. Sea anemone, Corynactis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 30.5b b. Sea anemone, Corynactis © Azure Computer & Photo Services/Animals Animals

Fig. 30.5c c. Cup coral, Tubastrea Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. c. Cup coral, Tubastrea © Ron & Valerie Taylor/Bruce Coleman, Inc

Fig. 30.5d d. Portuguese man-of-war, Physalia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. d. Portuguese man-of-war, Physalia © Runk/Schoenberger/Grant Heilman Photography

Fig. 30.5e e. Jellyfish, Aurelia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. e. Jellyfish, Aurelia © © Amos Nachoum/Corbis

Giant Jelly Fish

Coral Reef

Coral spawning

Portuguese Man of War

30.2 Introducing the Invertebrates Cnidarians: Phylum Cnidaria Hydra – a representative cnidarian (Class Hydrozoa) Freshwater, attaches to rocks and plants Small tubular polyp, sac-like body plan with a single opening Outer tissue layer: epidermis from ectoderm Inner layer: gastrodermis from endoderm Longitudinal and circular muscle fibers present Diffuse nerve net Digestion begins in gastrovascular cavity, completed in cells Can reproduce sexually and asexually (budding) Sexual reproduction Hydra develops an ovary or testis in body wall No medusae

© CABISCO/Visuals Unlimited Anatomy of Hydra Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. bud © CABISCO/Visuals Unlimited 28

Anatomy of Hydra mouth tentacle gastrodermis gastrovascular cavity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. mouth tentacle gastrodermis gastrovascular cavity epidermis

Anatomy of Hydra coiled thread trigger cnidocyte before discharge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. coiled thread trigger cnidocyte before discharge of nematocyst lid nematocyst filament spines cnidocyte after discharge of nematocyst barb 30