Biology 3484A/B Lecture Notes - Cambrian Explosion, Sea Anemone, Proterozoic
24 Dec 2012
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Document Summary
Eukaryote phylogeny: the cladogram shows that animals and fungi are more closely related to one another than they are to any other major clade. Animals (metazoa) are a branch of the opisthokonts, which are part of the unikonts. Choanoflagellates are unicellular, microscopic, heterotrophic, abundant, and ubiquitous in all aquatic environments. They are the closest living relatives of animals. Further study should lead to insights into the earliest events of animal evolution. They are an important component of marine plankton and the food chain. Animals have multicellular tissues and organs, though some are microscopic. Molecular data supports monophyly and so does the extra-cellular matrix (ecm). The ecm is composed of collagen and other molecules. Molecules are created inside cells, but the ecm exists outside cells. The ecm fills up the spaces between cells and serves as a structural element. It is flexible and can be squished and return to its original shape.
