BIO SCI 94 Lecture 12: Lecture 12

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

Document Summary

Homology of major cell type in sponge and choanoflagellate. Cells that can become specialized/haven"t been specialized yet (blast whatever) Tripoblasts tend to have a central nervous system (ganglia/brain) Cns - orient and move in one direction. Coelom - a fluid filled body cavity completely lined by mesoderm. Coelomates (has coelom have enclosed cavity completely lined with mesoderm) Acoelomates (no coelom - has no enclosed body cavity) Coelom reduced/lost several times (pseudo-coelomates - partially lined with mesoderm) Hydrostatic skeleton - system of body support with body wall surrounding fluid under compression. Must have worm design: tube within a tube with no limbs. Molecular clade named for ciliated structures for feeding (lophophore) and/or movement (trochophore) Tube worms in hydrothermal vents (mutualisms with chemosynthetic bacteria) 1 acre of top soil - 3 billion individuals. Tool kit genes (homeosis and heterochrony) --> rapid diversification when new ecological opportunity occurs. 2 pairs of antennae; 2 tagmata (cephalothorax, abdomen)