Speciation Adaptation What do you think about when

Speciation

Adaptation What do you think about when you see the word adapt? n Suitable How did organisms become suitable to their environment? n n Polar bear and the artic cold Cactus and the desert heat Variation leads to adaptation

Adaptation How do variations occur? n Mutations. Specifically, mutations that can be passed on to the offspring. Variation versus adaptation n n Variation may or may not improve survival Adaptation are variations that increase survival Therefore adaptation is evolution through natural selection

How can adaptation leads to isolation? What does Isolation mean? ? ? Reproductive Isolation n Cannot interbreed with another species Types of reproductive isolation n Behavioral – mating rituals Geographic – different places or locations Temporal – different times or seasons

Behavioral Adaptations Any type of behavior that benefits an organism in their environment For example n n n Migrating geese Mating dances Hibernation

Adaptations An organism does not have just one form of adaptation for reproductive isolation. Instead, organisms have a combination of ways. Let’s look at this example

Adaptation If organisms can adapt to their environment, how did we get a large number of different organisms (species)? n Species are organism that can breed and produce fertile offspring Natural selection brings about adaptations. Over a long period of time, natural selection can lead to new species. Otherwise known as speciation.

What are the steps for speciation? 1. 2. 3. Founding organisms (like founding fathers and mothers) occupy a niche The founding organisms must be separated from the rest of the population Changes in gene pool ¨ 4. Reproductive isolation ¨ n Relative frequency of the alleles must change They cannot interbreed anymore The process of speciation happens over a long period of time

Gene Flow (Thick Arrow – High) (Thin Arrow – Low)

Adaptive Radiation –the process of numerous species from a common ancestor introduced into an environment. Also known as divergent evolution Example using islands

Mainland to island n n Species A started on the mainland What happened over time?

Galapagos Finches

Island Forms Mainland ancestor

Concept Map Reproductive Isolation results from Isolating mechanisms which include Behavioral isolation Geographic isolation Temporal isolation produced by Behavioral differences Physical separation Different mating times which result in Independently evolving populations which result in Formation of new species