Week4 - Speciation and Extinction Species sometimes...

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Speciation and Extinction Species sometimes difficult to discern -- nature presents a continuum ecotype: distinct population occuring in a particular habitat geographic race: nonoverlapping ranges of subspecific category If a lineage has been successful, will see many derived species from a common ancestor with many adaptations. However, the inevitable fate of a species is extinction. Divergent vs. reticulate speciation Morphological species concept: species recognized if morphologically distinguishable from its close relatives Biological species concept: population of organisms that is actually or potentially reproductively isolated from other poulations (sensu Mayr 1963) Phylogenetic species concept: a species is any group of organisms in which all individuals share a unique, derived characteristic (synapomorphy) Evolutionary species concept: recognizes each independent evolutionary lineage as a species Classification in flux Microevolution and Macroevolution microevolution tends to focus on population-level processes, whereas macroevolution looks at major changes that occur over evolutionary time scales presented in the fossil record. Eldridge and Gould (1972) suggested two processes of macroevolution: punctuated equilibrium and species selection.
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Week4 - Speciation and Extinction Species sometimes...

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