BIOL 1111 Chapter Notes - Chapter 32: Acoelomorpha, Calcium Carbonate, Parasitism
27 Mar 2016
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Document Summary
Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers. Collagen and other structural proteins connect the cells. In most animals, gastrulation follows the formation of the blastula and leads to the formation of embryonic tissue layers. Most animals have hox genes that regulate the development of body form. Although hox genes have been highly conserved over the course of evolution, they can produce a wide diversity of animal morphology. Fossil history of animals spans more than half a billion years. Common ancestor of living animals likely lived between 675-800 million years ago. Animal kingdom = great diversity of living species + even greater diversity of extinct ones. Early soft-bodied members of the animal fossil record. Date from 565 to 544 mya - latest neoproterozoic. Show simple radial and bilateral (segmented?) forms. Earliest fossil appearance of many major groups of living animals. Period of greatest evolutionary change in the history of animal life.
