BIOL 172 Chapter Notes - Chapter 32: Sponge, Bilateria, Cnidaria
Document Summary
Chapter 32 an introduction to animal diversity. Animals cannot construct all of their own organic molecules so they ingest them by: Most animals feed by ingesting their food and then using enzymes to digest it within their bodies. Proteins external to the cell membrane provide structural support to animal cells and connect them to one another. Muscle and nerve cells central to animal lifestyle. Diploid stage usually dominates the life cycle. Haploid stage: sperm and egg cells are produced directly by meiotic division. Most animals species: a small, flagellated sperm fertilizes a larger, nonmotile egg, forming a diploid zygote. Zygote undergoes cleavage a succession of mitotic cell divisions without cell growth between the divisions. During the development of most animals: cleavage leads to the formation of a multicellular stage. Most abundant of these proteins: collagen called a blastula many animals takes the form of a hollow ball.
