BIO SCI 94 Chapter Notes - Chapter 35: Simian, Ovoviviparity, Hominidae

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Nancy Burley

Document Summary

Deuterostomes include the largest and most complex animals on earth. If coelom is present, it becomes the mesoderm from outpockets. Echinoderm - spines/spikes and is exclusively marine. Most deuterostomes are bilateral symmetric, but echinoderms evolved into five-sided radial symmetry (pentaradial symmetry) No head; interact with environment in all directions. Endoskeleton - hard structure that provides protection and support. Water vascular system - series of branching, fluid tubes and chambers. Forms the hydrostatic skeleton that operates as the feet. Synapomorphy that defines the echinoderm as a monophyletic group. 1) openings in the throat called pharyngeal gill slits. 2) dorsal hollow nerve cord - coordinate muscle movement. 3) stiff and supportive, but flexible rod called a notochord. 4) muscular, post-anal tail - tail containing muscle and extends past the anus. Made up of 3 major lineages - cephalochordates, urochordates, and vertebrates. Cephalochordates - small mobile, torpedo-shaped animals with a fish-like appearance. Pharyngeal gill slits present in both larvae and adults.