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Speciation and Adaptive Radiation Speciation Speciation is a name given to the theoretical process of creating a new species from pre-existing species of organism through modes of natural selection. Can not be done by means of artificial selection of different existing species. Niche Niche is the word used to describe the combination of an organism’s “profession” and the place where it lives. No species can occupy the same niche Due to COMPETITION Species that fill an unoccupied niche do so by adaptation This CREATES ENTIRELY NEW SPECIES Speciation Example According to the fossil record, Dinosaurs were the dominant species during the Mesozoic era and mammals were very few and far between. But around the time when the dinosaurs died out, new mammal species seemed to appear from nowhere…likely due to speciation and newly opened niches. Adaptive Radiation Reproductive Isolation Segregation of a population of species that DO NOT interbreed Need Physical/ Behavioral Barriers. If not isolated Blending of genes No New Specie If two populations become dissimilar in body structure and behavior, particularly mating behavior, what do you think will happen to them? •Decreased chance of breeding… This is called Behavioral Isolation Darwin’s Finches-Speciation STEP 1: FOUNDING FATHERS AND MOTHERS STEP 2: SEPERATION OF POPULATIONS STEP 3: CHANGES IN THE GENE POOL STEP 4: REPRODUCTIVE ISOLATION STEP 5: SHARING THE ISLAND Darwin’s Finches Another example There are many different species of Galapagos Tortoises alive today (and many extinct). Each seems to have been derived by speciation from a common single ancestor species. Under what circumstances can two species coexist successfully? What will happen if the niches of two species are too similar? How might further evolution occur?