18.Multicellularity GAE

18.Multicellularity GAE - 3/5/11 Thinking about...

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1 Thinking about mul±cellular organisms Fig. 31.11A Learning objec±ves: 1) To understand how biologists fgure out li²e cycles; 2) To appreciate the advantages and the challenges o² evolving into large mul±cellular organisms; and 3) To understand the consequences o² size. Keep the worksheet as a study guide Major themes in eukaryotes so ²ar Pro±sts – endosymbiosis – process, evidence, bioenerge±cs, consequences general eukaryo±c ²eatures; major groups li²e cycle and origin o² sex eukaryo±c pathogens Di³usion – physical process, evolu±onary constraint Plants – li²e cycle phylogene±c tree – adapta±ons to land environment Fungi – growth ²orm and nutri±onal strategy root symbionts with early plants and agricultural crops ²ungal pathogens and human signifcance GAE Part 1. Modeling Life Cycles Previous GAE’s – constructed different models for biological energy flow, phylogeny, endosymbiosis, and diffusion Life cycle diagram – simple model of the major stages in the life of an organism. One approach – evolutionary reasoning explains why a life cycle has certain features. For example, the plant life cycle exhibits alternating haploid (1n) and diploid (2n) generations Why the haploid gametophyte (1n) stage?______________ Why the diploid sporophyte (2n) stage? ________________ Complementary approach – mechanistic reasoning focuses on the processes involved in the cycle. Generalized sexual life cycle in eukaryotes
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18.Multicellularity GAE - 3/5/11 Thinking about...

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