BIOL 2P05 Lecture Notes - Lecture 22: Axolotl, Heterochrony, Neoteny
14 Mar 2018
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Document Summary
Regional specification: process that creates spatial patterns within an organism. Overall control of timing: integration of various processes. When comparing developmental stages of closely related species, general traits develop before the specialized traits . An organism produces new species by adding something new to their phylogeny. Heterochrony: a developmental change in the rate of events, leading to changes in size and shape relative to ancestral species. Involves a shift in the timing of developmental processes so an event occurs earlier or later in a taxon compared to its ancestor. Juvenile features are retained in adults (decreased development by sexual maturity) Progenesis: reproductive traits appear earlier (period of growth stops prematurely. Neotony: rate of growth is less - somatic traits retarded (growth rate is less) Species mature later in adulthood and take on traits that haven"t been seen yet (increased development by sexual maturity) Hypermorphosis: period of growth in the descendant is extended.
