The Process of Speciation

What is Speciation? The formation of a new species Species: a group of organisms that can breed with one another and produce fertile offspring In order to create a different and new species, you must change the gene pool But, how do you change the gene pool?

Reproductive Isolation To create a new species, there must be isolation Reproductive Isolation: When members of 2 populations can no longer interbreed and produce fertile offspring; now have separate gene pools Caused by 3 ways

Behavioral Isolation 2 populations are capable of interbreeding but have different courtship rituals –Bird of Paradise Mating Dance –Mating Calls/Songs Humpback Whale –Calls/Whistles of Meadowlark Bird animals/

Geographic Isolation Two populations are separated by geographic barriers Ex: Rivers, Mountains, Bodies of Water May not be permanent (waters may flood together, land bridge between islands)

Squirrels and the Grand Canyon

Reproductive Temporal Isolation 2 or more species reproduce at different times Ex: 3 species of orchids release pollen only one day a yr. Since they don’t release pollen on the same day, they can never cross pollinate or interbreed. Ex: eastern spotted skunk mates in late winter and western spotted skunk mates in late summer.

Pulling It All Together- Darwin’s Finches FOUNDERS ARRIVE GEOGRAPHIC ISOLATION CHANGES IN THE GENE POOL REPRODUCTIVE ISOLATION ECOLOGICAL COMPETITION CONTINUED EVOLUTION