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Ch. 32. I. Phylogeny- Evolutionary development of a species based on DNA from organisms and embryology. A. Major Branches of the Animal kingdom _. 1. Subkingdom Parazoa a. Phylum Porifera _ ( sponges) b. Simple structure separates them from all other animals
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I. Phylogeny- Evolutionary development of a species based on DNA from organisms and embryology. • A. Major Branches of the Animal kingdom_. • 1. Subkingdom Parazoa • a. Phylum Porifera_ ( sponges) • b. Simple structure separates them from all other animals • 2. Subkingdom Eumetazoa (true tissues) • a. Radial symmetry (_oral and aboral) • b. Bilateral symmetry, dorsal (top), ventral(bottom), anterior (front/head), posterior(_rear/tail), right and left. • 1. Cephalization - Concentration of sensory structures at anterior end.
A. Development and Body plan • 1. Germ Layers = will form the tissue of the developing embryo. • a. All eumetazoa animals develop 2_ germ layers (endo and ecto derm) • b. Cnidaria is the phylum of jellies develop only 2 layers (endo and ecto derm).
A. 3 Germ layers of Bilateral animals • 1. Ectoderm • a. Covers surface • b. Animal covering and central nervous system • 2. Endoderm • a. Innermost layer • b. lines the developing gut • c. Lines the digestive tract and pockets give rise to _liver_ and _lungs__ in vertebrates_. • 3. Mesoderm • a. between endo and ectoderm • b. Forms muscles and most organs between digestive tract and outer covering
A. Body _Cavity_. • 1. Acoelomates= no _cavity between digestive tract and outer body wall. • a. Filled with mesoderm • 2. Pseudocoelomate = fluid filled cavity • a. Not completely lined with mesoderm • 3. Coelomate = fluid filled cavity lined with mesoderm • a. Inner and outer mesoderms connected
I. Zygote development • A. _Protostome vs. Deuterostome_ • 1. Animals are first classified based on symmetry and germ layers • a. no symmetry = _sponges • b. radial _symmetry_ = Cnidaria • c. Two layers = Cnidaria • 2. Animals then classified by body cavity • 3. Animals are classified by evolutionary lines of development • B. Protostomes • 1. Spiral_cleavage_ • 2. Mouth first • 3. determinate • C. Deuterostomes • 1. Radial cleavage • 2. Anus first • 3. _indeterminate