BIO 200 Lecture Notes - Lecture 18: Calcareous Sponge, Symmetry In Biology, Entoprocta
27 Jun 2015
School
Department
Course
Professor
Document Summary
Lecture 18: animal diversity and the basal animals. Animal traits: heterotrophic, multicellular, no cell walls, motile, reproduce sexually, usually symmetrical, characteristic embryonic development, specialization of tissues and cell types, increasing complexity, larger size, development of coelom, segmentation, independent movement, redundancy of function, strength and flexibility. Arrow worms are either the most basal protostomes, or they are the outgroup to the protostomes. Lophotrochozoans regenerate cells by adding layers to existing mass: bryozoans, entoprocts, platyhelminths (flatworms), rotifers, nemerteans (ribbon worms), annelids, and mollusks. Ecdysozoans regenerate cells by exoskeleton molting: deuterostomes (anus first) Sponges: closely related to ancient choanoflagellates, most basal lineage of animals, not a monophyletic group. Larvae are free-swimming: adults are anchored to rocks, huge range in size, do not have true tissues. Loose body organization: high level of specialized cells, choanocytes have flagella that beat in unison. Pumps water in to collect nutrients: water pores are holes between choanocytes, usually reproduce sexually.
