BIOL 1108 Lecture Notes - Lecture 35: Symmetry In Biology, Eumetazoa, Animal
Document Summary
Fungi, plantae, and animalia separately evolved from single celled eukaryotes eukarya is a monophyletic taxon with multiple synapomorphies of cell structure. Eukarya includes both single celled and multi celled organisms. Within the eukarya, there are multiple major groups with unclear relationships. The choanoflagellates resemble a cell type in basal animals, reflecting a sister taxon relationship. Molecular and structural characters and common features of development strongly support the common evolutionary history of all animals. Metazoan phylogeny is based in part on features of body plan and development. There are differences among animals in grades of complexity and guts. Metazoan phylogeny is being revised by molecular data. The sponges are the most basal metazoans. Sponge bodies lack tissues and guts but have skeletal support. Most are marine, but a few percent of species are freshwater sponges. Habits include filter feeding, sex, and a larval stage. Sponges have been placed in the phylum porifera, which is not monophyletic.
