Please enable JavaScript.
Coggle requires JavaScript to display documents.
Phylogeny and Evolutionary History (Reading Phylogenetic Trees (Unrooted…
- Phylogeny and Evolutionary History
-
-
Homology and Analogy
Homologous trait: trait found in 2 or more species because they inherited it from the same ancestor
Analogous trait: shared by 2 or more species not because of a common ancestor, but because evolutionary processes have generated similar traits in each species
Divergent evolution: when closely related species diverge from one another as NS operates differently on each of them
Convergent evolution: 2 or more species become more similar to one another due to being exposed to similar selective conditions (produces analogous traits)
Derived trait: a trait that evolved from another trait (eg. dark colour is a derived trait if it has been derived from an ancestor with a light colour)
Synapomorphy: shared derived trait (when population split prior to acquisition of trait A, then split again after acquiring trait A. Trait is now shared between two new populations)
Homoplasy: analogous trait
Symplesiomorphy: an ancestral shared trait (eg. dark colour) that is not shared by two most closely related species due to a recently derived new trait (light colour). May lead to incorrect conclusions about evolutionary relationships
Polarity: the order of appearance of traits in evolutionary time (done by using multiple outgroups and analysing different cases). Using multiple outgroups is useful as we know the relationship of taxons (in an uncertain polytomy) to the outgroups. The likely ancestral state will be found in outgroups.
Parsimony: approach of trying to explain observed character states in a phylogeny by a minimum number of evolutionary changes
-