07 Evo-Devo Origins of Body

07 Evo-Devo Origins - Lecture Notes Evo-Devo Origins of the Body 1 embryos represent basic body plan that can be,infinitely modified an old idea

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Lecture Notes 9/21/07 Evo-Devo Origins of the Body 21/09/2007 12:07:00 embryos represent basic body plan that can be ‘infinitely’ modified an old idea, helped Darwin formulate his theory How does basic body plan work? How does it evolve? Three Germ Layers ectoderm   neural tube mesoderm   central axis (notochord), segmented mesoderm (somites),  central body cavity (coelom) endoderm   gut “blind watchmaker” analogy evolution by natural selection is agentless (blind) organisms are complex (like a watch) having nothing “guide” evolutionary changes to development is like  assembling a watch “blind” Two Solutions to “blind watchmaker” 1. Evolutionary changes that generate complexity occurred from  many  intermediate steps o i.e. the eye: started out w/ innervated pigment cells, then get  invagination, etc. etc. change and complexity o body has many parts (  modules ) that develop via a hierarchical  (branching) process w/ many  interactions  between modules
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o modules genes cells  germ layers segments o interactions growth movement induction o interactions between modules cause  integration:  parts become  combined into a whole i.e. folding of body walls to create tube-shaped embryo variation happens: genetic mutations    variation in modules  (e.g. # of somites), variation in how modules interact (e.g.  Modules are like legos, interactions are the different ways you can snap them 
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This note was uploaded on 04/29/2008 for the course LIFE SCIEN 9007 taught by Professor Georgev.lauder,andrewa.biewener,petert.ellison,anddaniele.lieberman during the Spring '08 term at Harvard.

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07 Evo-Devo Origins - Lecture Notes Evo-Devo Origins of the Body 1 embryos represent basic body plan that can be,infinitely modified an old idea

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