Animal Kingdom Morphology Organizer

Symmetry Radial Symmetry Bilateral Symmetry

Radial Symmetry Round animal Any cut through the center creates symmetrical halves Bilateral Symmetry There is a definite right and left side, front and back, top and bottom. There is only one way to cut the animal into symmetrical (mirror- image) halves.

Bilateral Symmetry Includes “Cephalization” Bilaterally symmetrical organisms have a definite “head” end, and a definite “tail” end.

Germ Layers Germ layers are embryonic tissues that are destined to become different specialized organs.

Germ Layers (continued) Organisms may have either: –no distinct germ layers –2 germ layers (diploblastic) –3 germ layers (triploblastic)

Developing embryo with 2 germ layers. Ectoderm - (Forms skin, nerves, teeth) Endoderm - (forms liver, lining of digestive & respiratory systems)

Embryo with 3 germ layers Mesoderm – becomes skeleton, muscles, muscular covering of organs

Body Cavity In triploblastic organisms (3 germ layers), there may be: No body cavity (acoelomate) Pseudocoelom (false body cavity) True coelom

Body covering (from ectoderm) Tissue- filled region (from mesoderm) Digestive tract (from endoderm) Acoelomate. Acoelomates lack a body cavity between the digestive tract and outer body wall. (c)

Pseudocoelomates have a body cavity between the mesoderm layer and the endoderm layer. Body covering (from ectoderm) Muscle layer (from mesoderm) Digestive tract (from endoderm) Pseudocoelom

Coelomates have a true coelom, a body cavity completely lined by tissue derived from mesoderm. Digestive tract (from endoderm) Coelom (cavity within the mesoderm)

Digestive System None Incomplete (one opening, sac- like body) Complete (mouth at one end, anus at the other)

Protostome vs. Deuterostome In embryonic development of protostomes, the mouth develops first, then the anus. In deuterostomes, the mouth develops second.

Circulatory System - Open Heart Tubular heart Blood is pumped into open areas surrounding muscles and organs.

Circulatory System - Closed Heart Dorsal vessel (main heart) Small vessels in each organ Blood is enclosed in vessels throughout the whole body.

Body Segmentation Segments are repeating units. Animals may be: Non-Segmented Segmented In addition, they may have segmented limbs. Some have a notochord or vertebral column.

Non-Segmented Animal

Segmented Animal (fossil)

9 Important Animal Phyla Porifera - Sponges Cnideria – Jellyfish, anemones, coral Platyhelminthes – Flatworms Nematoda – Roundworms Mollusca – Mollusks (clams, snails)

9 Phyla (continued) Annelida – Segmented worms Arthropoda – Insects, crustaceans Echinodermata – Sea stars & urchins Chordata – chordates, vertebrates

9 Phyla Cladogram Porifera Cnideria Platyhelminthes Nematoda Mollusca Annelida Arthropoda Echinodermata Chordata

Porifora (sponges) Symmetry – None (Assymetric) Germ layers None

Porifera (continued) Body cavity – None Digestive System – None Proto / Deutero – N/A Circulatory System – None Segmentation? – None

9 Phyla Cladogram Multicellular body (first animals)

Cnideria (jellyfish, anemones) Symmetry - Radial Germ layers - 2 (diploblastic)

Cnideria (continued) Body cavity – None Digestive System – Incomplete Proto / Deutero – N/A Circulatory System – None Segmentation? – None

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry

Platyhelmenthes (Flat worms) Symmetry - Bilateral Germ Layers - 3 (triploblastic)

Platyhelmenthes (continued) Body cavity – None Digestive System – Incomplete Proto / Deutero – N/A Circulatory System – None Segmentation? – None

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers

Nematoda (round worms) Symmetry - Bilateral Germ Layers - 3 Body Cavity - Pseudocoelom (Incomplete) 25 µm

Nematoda (continued) Digestive System – Complete Proto / Deutero – Protostome Circulatory System – None Segmentation? – None

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers Pseudocoelom Complete Digestive System- Protostome

Mollusca (clams, snails, squid) Symmetry - *Bilateral in larva, adults may be assymetric

Mollusca (continued) Germ Layers - 3 Body Cavity – True coelom Digestive System – Complete Proto / Deutero – Protostome Circulatory System – Open Segmentation? – None

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers Pseudocoelom Complete Digestive System Coelom Complete Digestive System- Protostome Open Circ.

Annelida (segmented worms) Symmetry - Bilateral Germ Layers - 3 Body Cavity – True Coelom

Annelida (continued) Digestive System – Complete Proto / Deutero – Protostome Circulatory System – Closed Segmentation? – Segmented

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers Pseudocoelom Complete Digestive System Coelom Segmented Body Complete Digestive System- Protostome Open Circ. Closed

Arthropoda (insects, crustaceans, etc.) Symmetry - Bilateral Germ Layers - 3 Body Cavity – True Coelom

Arthropoda (continued) Digestive System – Complete Proto / Deutero – Protostome Circulatory System – Open Segmentation? – Segmented body, segmented limbs

Annelid vs. Arthropod

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers Pseudocoelom Complete Digestive System Coelom Segmented Body Complete Digestive System- Protostome Deuterostome Open Circ. Closed

Echinodermata (sea stars, sea urchins) Symmetry - *Bilateral in larva, 5-part radial in adult Germ Layers - 3 Body Cavity – True Coelom

Echinodermata (continued) Digestive System – Complete Proto / Deutero – Deuterostome Circulatory System – *Water Vascular System Segmentation? – *Larva are segmented

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers Pseudocoelom Complete Digestive System Coelom Segmented Body Complete Digestive System- Protostome Deuterostome Open Circ. Closed 5-part Radial Symmetry

Chordata (chordates, vertebrates) Symmetry - Bilateral Germ Layers - 3 Body Cavity – True Coelom

Chordata (continued) Digestive System – Complete Proto / Deutero – Deuterostome Circulatory System – Closed Segmentation? – Segmented body, some with segmented limbs, notochord or vertebral column

9 Phyla Cladogram Multicellular body (first animals) 2 germ layers Radial Symmetry Bilateral Symmetry Three Germ Layers Pseudocoelom Complete Digestive System Coelom Segmented Body Complete Digestive System- Protostome Deuterostome Open Circ. Closed Notochord 5-part Radial Symmetry

9 Phyla Cladogram Porifera Cnideria Platyhelminthes Nematoda Mollusca Annelida Arthropoda Echinodermata Chordata