BIOL211 Lecture Notes - Paraphyly, Lumbar Vertebrae, Axial Skeleton
4 Feb 2013
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Document Summary
Monophyletic a group (genus, phylum, class, order, etc) comprising of all the descendents of a common ancestor. Paraphyletic group including most but not all descendants of an ancestral form. Phylum (chordate) > subphylum (vertebrata) > class (mammalia > subclass > order family > Homoplasy similar in appearance, can reflect common ancestry/function, but not always. Homologous structures evolve from a corresponding structure in a common ancestor. Analogous structures may appear similar, but similarity is shaped by adaptation to a common function and does not reflect close evolutionary relationship. Vestigial structures not functional, but represent features functional in ancestors. Convergence different ancestors producing similarity in animals due to adaptation to similar environmental conditions (ie: fish-like body of dolphins) Parallelism similarity in animals with similar but distant ancestors due to adaptation to similar environmental conditions. Recapitulation ancestral features evident in embryo of a descendent. Paedomorphosis ancestral juvenile features evident in the adult of a descendent.
