ZOO 2090 Lecture Notes - Lecture 2: Evolutionary Developmental Biology, Nervous Tissue, Haikouichthys

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2090
• Professor: Jinzhong Fu

Document Summary

Slide 24 from last lecture: delete diagram on right/ misleading. Was considered closely related to vertebrates because they share segmented trunk muscles. Filter feeding by pharyngeal ltration system driven by cilia. No differentiated brain, special sense organs or heart. 1) fossil record: most direct, but never complete. 2) phylogenetic approach: using shared derived characters to determine common ancestry. Ancestral, derived or advanced? no species is better than the other (ex. person vs sh in a given environment). Pikaia of the burgess shale (middle cambrian ~520 mya) Rudimentary vertebrae surrounding a strengthened notochord, eyes might be present. **but, haikouella might be a non-vertebrate basal deuterostome. Oldest vertebrates ! (early cambrian of north america, e. g. burgess shale, marble canyon) Conway-morris and caron (2014) shows a notochord, pairs of camera eyes and nasal sacs, sh-like myomeres and tail, as well as bipartite branchial bars associated with external gills. 7 pre-cam there were single celled organisms/simple organism.