BIOL 2002 Chapter Notes - Chapter 25: George Gaylord Simpson, Zygote, Leigh Van Valen
Document Summary
Number of species ranges from 5 to 50 million. Subspecies = a subdivision of a species used when 2 or more geographically restricted groups of the same species differ but not enough to warrant separate species. Ecotype = genetically distinct populations adapted to their local environment. Species = group of organisms that share a distinctive set of attributes in nature. Usually cannot successfully interbreed with members of other species. Share an evolutionary history distinct from other species. Hard to group bacterial species because of horizontal gene transfer. Most common characteristic for species are morphological traits, ability to interbreed, molecular features, ecological factors and evolutionary relationships. Drawbacks when deciding how many traits to consider. Some quantitative traits are variable and hard to analyze. Members of same species can look dissimilar. Members of different species can look similar. Can be difficult to distinguish if 2 populations re reproductively isolated if they are not geographically close.
