BIOL 2200 Chapter Notes - Chapter 667-678: Ectoderm, Body Cavity, Diploblasty
14 Mar 2017
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Animals differ from plants and fungi in that they cannot produce their own food, nor can they absorb it. Animals ingest food and use enzymes within the body to digest food. Proteins outside of the cell membrane support the cells, rather than having cell walls for support. Collagen is the most abundant of these proteins that is unique to animals. Tissues = groups of similar cells that act as a functional unit. Muscle and nerve cells are central to animal lifestyle. Most animals reproduce sexually, with the diploid stage being the predominant life stage. Sperm and egg cells are produced by meiotic division in the haploid stage. In most cases, a small flagellated sperm fertilizes a larger non-motile egg to form a diploid zygote. Cleavage = cell divisions without mitotic growth in between divisions. Blastula = multicellular stage in which many animals take the form of a hollow ball.
