WHAT ARE THEY?
Inheritance - Offspring look like their parents
Differential Survival - External conditions can affect survival
Extinction - Some traits are not suited to survival and those with them will die out.
C.V. (2015, May 13). Bengal Tigers. Retrieved April 4, 2016, from http://btiger.weebly.com/
Freeman, S., Quillin, K., Allison, L., Black, M., Podgorski, G., Monroe, J., & Taylor, E., (2014). Homeostasis, How Do Animals Regulate Body Temperature? In Biological Science (5th. Edition ed., Vol. Volume 3, pp. 853-858). Glenview, Illinois: Pearson Education.
M. S. (22, December 2014). White Seals. Retrieved April 4, 2016, from http://arabse1.blogspot.mx/2010/11/white-seals-physical-features.html
U. (2008, April 30). Polar Bears. Retrieved April 4, 2016, from https://en.wikipedia.org/wiki/Polar_bear