BIO 309 Lecture Notes - Lecture 26: Species Richness, Biogeography, Ice Age
Document Summary
Study of ecological structure and process at large geographic scales. Williamson: increased diversity with increasing land area, increased diversity with closer isolation. Lomolino: negative relationship between isolation and species number, immigration is important in maintaining diversity. Macarthur and wilson: species diversity as result of balance of immigration and extinction rates. Rate of extinction would rise with increasing number of species on an island. Presence of more species creates a larger pool of potential extinctions. As number of species increases, population size of each must diminish. As number of species increases, potential for competitive interactions between species will increase. Small near and large far support intermediate number. Simberloff and wilson: mangroves, species number was constant, but composition changed, defaunated islands nearly returned to original species number, but composition changed. Species richness increases from middle and high latitudes to the equator: time since perturbation. More species in tropics because tropics older and disturbed less frequently: productivity.