BIO 124 Lecture Notes - Lecture 3: Phylogenetic Tree, Pattern Formation, Branch Point
6 Apr 2016
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Document Summary
Tissues organ organ systems organism. Cell diferentiation- cells become specialized in structure & function. Morphogenesis- physical process that gives organism its shape. Cytoplasmic determinants- maternal substances in egg that inluence early development. Induction- signal molecules from embryonic cells that cause transcriptional changes in nearby target cell. Systematics- organisms group based on shared characteristics and molecular sequence date; reconstruction & study of evolutionary relationships. Phylogeny- hypothesis about patterns of relationships among species. Phylogenetic trees show a pattern of descent, not phenotypic. Derived character- similarity from most recent common ancestor of entire group. Ancestral character- similarity that arose prior to most common ancestor. Only shared dervied characters inform us about evoltuionary. Outgroup- species closely related to, but not a member of, the group in question. Autopomorphy- derived state seen in a single taxon. Symplesiomorphies- shared ancestral state (results in homoplasy- a shared character that has not been inherited by a common ancestor) Homoplatic convergence- evolved independently in diferent clades of extinct mammals.
