Animal Kingdom Morphology Organizer Symmetry Radial Symmetry Bilateral

Animal Kingdom Morphology Organizer

Symmetry Radial Symmetry Bilateral Symmetry

Radial Symmetry Bilateral Symmetry • Round animal • Any cut through the center creates symmetrical halves • 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 (mirrorimage) 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

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

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

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

Digestive System • None • Incomplete (one opening, saclike 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 Blood is pumped into open areas surrounding muscles and organs. Heart Tubular heart

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 Chordata Echinodermata Platyhelminthes Cnideria Porifera Mollusca Annelida Nematoda Arthropoda

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 Radial Symmetry 2 germ layers Multicellular body (first animals)

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

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

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

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

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

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

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

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

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

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