BIS2C_Lect34_Ward_Chordata+1_ppt - BIS2C Winter 2012 (Ward)...

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1 BIS2C Winter 2012 (Ward) Lecture 34. Chordata, Part 1 Today's lecture (16 March) finish Echinodermata introduction to Chordata major features early chordate evolution origin of vertebrates jawless and jawed fish Monday lecture tetrapods, especially amniotes convergent evolution BIS2C Winter 2012 Review Session (Tuesday, 20 March) 1:00 pm – 3:00 pm 123 Sci Lec Posted on Smart Site (under Resources/Exam Study Guides): Final Exam Study Guides (Metazoans; Microbes/Plants/Fungi) BIS2C: Room assignments for final exam Sec. A March 21 st , 6:00-8:00 pm Chem 194 A-L Haring Hall 2205 M-We Bainer 1132 Wi- Z Sec. B March 24 th , 6:00-8:00 pm Young 198 A-K Haring Hall 2205 L-S Wellman 106 T- Z California sea otters eat urchins. Sea urchins consume kelp. When sea urchins are abundant they can destroy underwater kelp forests. Clicker Question 1 Sea otters can be considered a “keystone species” in this system because a. The kelp forests flourish when otters are removed. b. Their presence or absence has a large effect on ecosystem structure. c. They provide the key to understanding why sea urchins eat kelp. d. Their abundance is positively correlated with the abundance of other animals in the environment. e. They have evolved to eat sea urchins. Sea cucumbers (Holothuroidea) soft-bodied and slug-like (ossicles much reduced) greatly elongated oral/aboral axis, secondarily bilateral grazers, suspension feeders
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2 = pentaradial symmetry = partial bilateral symmetry Hypothesized phylogeny of major echinoderm groups Sea cucumbers (Holothuroidea) can expel parts of their gut as anti-predator defense ( ) Sea cucumber with expelled Cuvierian tubules Major lineages of metazoans Deuterostome traits radial cleavage blastopore anus enterocoely What are chordates?
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BIS2C_Lect34_Ward_Chordata+1_ppt - BIS2C Winter 2012 (Ward)...

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