BIOL 242 Study Guide - Midterm Guide: Action Potential, Sodium Chloride, Homeostasis
Document Summary
Common to other groups: eukaryotic (domain, multicellular, heterotrophic- Unique to animals: motile- they can move, lack cell wall. Collagen- most abundant protein in humans, import to bones, makes bones less brittle. Both are fibrous proteins formed by skin cells: cholesterol- maintain membrane fluidity, gametic life cycle. Molecular evidence of steroids and sediments are dated at 710 million years ago. Sister group to animals are choanoflagellates (unicellular), lots of morphological evidence link these two. First common ancestor of animals are dated to 770 million years ago. Spicules- provide structural support and deter predators: produced by amoebocytes, silica, calcium carbonate, or sponging. 4 basic groups: hydrozoans, scyphozans (jellies, cubozoan (sea wasp, anthozoan (sea anemone) 2 body plans: polyp and medusa. Polyp mouth/ anus is on top while medusa is on bottom. Mesoglea- internal skeleton: motile and sessile forms, radial symmetry, carnivores. Gastrovascular cavity (one opening: two embryonic tissue layers. Pre-cambrian forms: grazers, filter feeders, scavengers; generally soft.
