Island biogeography and ecological succession Today (11/15) we will… Learn about island biogeography and ecological succession (Two important concepts!) Use the rest of class to finish up your Darwin’s labs Potluck sign ups for next Wednesday? Island biogeography and ecological succession Islands Islands are unique. They are isolated, so evolutionary processes work at different rates. No gene flow Much faster selection As a result, evolution happens much more rapidly! Bird example Think about the bird beak experiment you did yesterday. You each had different types of beaks. Lets say that you all came from a large continent and were blown to a far away island. On that island, there are limited food sources, so the birds that beaks perform the best will be able to become established. The birds that perform the worst will become extinct. This is island biogeography in essence! What are you even talking about Mr.? The theory of island biogeography – it’s a dynamic equilibrium between the immigration rate and the extinction rate of species colonizing an island. Factors affecting this theory The size of the island – larger islands holds more species The distance of where animals/plants recruit from – the farther the island, the harder it is to immigrate there! Important factoid – Does not have to be an island. Anywhere that is geographically isolated will work! We will simulate this tomorrow! Don’t skip class! Will be fun! Succession At first in a completely new environment, there is no living organisms. Gradually, things start to colonize it. Take a new volcanic island for example. Seeds will blow on the wind and settle on the island. Some of those seeds will eventually sprout, forming the first settlers on that new island. This is an example of sucession! Succession Primary succession occurs with where there is no life, these are the first colonizers. Primary succession The first species to colonize a newly formed environment are called pioneer species. Eventually, things balance out… Succession will eventually stop and form a climax community. This is a stable community dominated by a small number of prominent species. Secondary succession Eventually, there comes a point where there is a large scale disturbance (fire, tornado, etc.) that wipes mostly everything out. As new species colonize the area with old species present, this is secondary succession. The process repeats all over again. Fun! Start to finish.