BIO 200LLB Lecture 20: Bio Lecture 20

• School: University at Buffalo
• Department: Biological Sciences
• Course: BIO 200LLB
• Professor: J. Poulin

Document Summary

Ancestral deuterostomes have traits we see in modern echinoderms and chordates. Pentaradial symmetry means there are five axes of symmetry. Shows up as symmetry in fives or multiples of fives. Echinoderms aren"t more closely related to the more basal radial groups. They have bilateral larvae stages and shows that they have close connection to the bilaterians. Water vasculature system: water filled canals that lead from the interior, to the extension of the bodies (tube feet). Used for feeding, gas exchange, and locomotion: sea water enters the body through small holes or a pore (madreporite) and flows through into the ring canal. Oral surface (underneath and what the animal crawls on). Most use sexual reproduction: sexes are separate. Gametes are usually released into the water and externally fertilized. There are 20 extinct classes but only 3 extant groups: crinoids, echinozoans, and.