Animal Kingdom Phylogeny - Cladogram Section 29-1 Echinodermada Chordata Arthropoda Annelida Mollusca Radial Symmetry Nematoda Platyhelminthes Pseudocoelom Cnidaria Deuterostome Development Radial Symmetry Coelom Protostome Development Porifera Three Germ Layers; Bilateral Symmetry Tissues Multicellular Single-celled ancestor

Egg Development Sexual reproduction: zygote fertilized egg blastula hollow ball of cells with blastopore (inner tube) Protostome Mouth formed from blastopore Deuterostome Anus formed from blastopore

Germ Layers Cells arranged into layers and from there specific organs or structures are formed. 1. Ectoderm – outer layer, forms skin, 2. Mesoderm – middle layer, forms muscles 3. Endoderm – inner layer, forms digestive tract

Body Symmetry Asymmetrical – no symmetry, no tissue organization. Radial – body parts extend from center of body. Cells start forming first tissues. Bilateral – Mirror image of right and left sides externally. Tissues well developed.

Body Cavities A body cavity is called a Coelom (see-lome). Located between the digestive tract and the body wall inside the animal. Allows for expansion and development. Classification of organisms: 1. Acoelomate – no cavity present 2. Pseudocoelomate – partial body cavity 3. Coelomate – body cavity completely lined with mesoderm.

Cephalization Concentration of sense organs and nerve cells at the front of the body. Animals with bilateral symmetry exhibit it. More complex animals the more pronounced their cephalization

Animal Kingdom Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelida Arthropoda Echinodermata Chordata

Animal Kingdom Phylogeny - Cladogram Section 29-1 Radial Symmetry Pseudocoelom Radial Symmetry Single-celled ancestor