ANT 201 Chapter Notes - Chapter 5: Neural Crest, Peripheral Nervous System, Agnatha
11 Dec 2016
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Document Summary
Our brain is an offshoot of a particular lineage, not a culmination of the past. Evolution leads to larger size, greater complexity, more info storage; if evolution happened again or somewhere else, same trends are likely: underscores mayr"s point: pure darwinian selection can make things work better. Negate role of increasing complexity in history of life. Convergent evolution: emergence of fxnally and strxally similar adaptations in lines separated before their appearance (common in nervous system: mechanisms of brain evolution. Induction: differentiated and juxtaposed embryonic tissues use chemical messages to produce further changes in either or both tissues: outer/ectodermal layer induced to become neural tissue in embryo. Homeobox gene patterning: critical role in specifying the linear anatomy of the neural tube. Invasion: invasion of cell territories by projections from adjacent or distant cell groups and subsequent competitive replacement of invading projections from one source with those from another: mutations in cell/surface adhesion molecules (cams and sams) -> evolving patterns.
