BIOL 224 Lecture Notes - Lecture 1: Blastula, Gastrulation, Symmetry In Biology
Document Summary
Bio 224 - introduction to animal diversity: form & What is an animal: 1) multicellular eukaryotes 2) heterotrophs (no cell walls) 3) reproduce asexually or sexually. Origin: agellated protist > cells in these protists became more specialized (speci c functions) and layered [picture in powerpoint] Animalia: monophyletic > evolved from a common ancestor but there is one genetically determined body plan for each animal phyla. Animals can be characterized by features of their body plan : vary in: embryonic development, specialized tissue types, body cavity type & body symmetry. Sexual reproduction: 1) undergo meiosis to produce gametes 2) sperm + egg fuse to form zygotes which develop into new individuals. **** picture/diagram of morula and blastula in powerpoint slide **** Blastula invaginate & undergoes further differentiation into 3 germ layers: ectoderm (skin and nervous system), mesoderm (muscles and skeleton), endoderm (digestive tract) Germ layers differentiate to form tissues and organs, Most animals are triploblasts > have 3 germ layers.
