Stabilizing selection favors average or intermediate traits in a population, reducing variation. This causes the population to stay the same over time. Directional selection favors one extreme trait, causing the population to evolve in one direction. Disruptive selection favors two extreme traits, leading to the emergence of two new species separated by intermediate forms. Geographic isolation and behavioral differences can cause speciation as populations separated by barriers evolve independently.

5. Muskopf, Shannan. Online Images. The Biology Corner . 13 May 2007. http://www.biologycorner.com/bio3/notes-chap17.html

6. Organisms from the same species develop different traits to survive their environment. Adaptive Radiation: This is a type of divergent evolution where a species evolves to fit into an open niche. http://www.biology-online.org/2/15_adaptive_radiation.htm

8. Spotted owl subspecies living in different geographic locations show some genetic and morphological differences. This observation is consistent with the idea that new species form through geographic isolation . http://evolution.berkeley.edu/evolibrary/article/_0_0/evo_45

9. These organism are not from the same species, and they are not related. They developed similar adaptations because they have the same niche. They all eat ants. http://www.pbs.org/wgbh/evolution/library/01/4/l_014_01.html

10. Yucca flowers are a certain shape so that only the yucca moths can pollinate them. http://biology.clc.uc.edu/Courses/Bio303/coevolution.htm