Saturday, September 19, 2009
Origin of The "Arctic Fox"
The Arctic Fox (Alopex lagopus) is an amazing creature that lives year round in the harsh conditions of the Arctic Tundra. Many sources claim that the Arctic fox is part of the Vulpes genus—along with just about every other fox—but in fact all taxonomy lists classify them as Alopex lagopus ("Virginia Hayssen," n.d.). The Arctic Fox originated from the Red Fox (Vulpes vulpes), some 1.2 million years ago (Nowak, 2004). As Red Fox populations moved north and south, some moved into much colder conditions and became isolated. There, they had to evolve rather quickly to keep up with the frigid conditions of the frozen arctic tundra.
As a result of Natural Selection, the Red Fox’s red colored fur changed dramatically into a purely white fur in the winter and brown in the summer. The white coat grows very thick and covers their ears and even their paws. In the winter they follow polar bears around, scavenging off of the scraps that the bear kills leave behind ("Planet Earth: Ice Worlds: Polar Bear and Cubs," n.d.). In the summer months, this remarkable creature’s fur turns from pure white to brown. This camouflages it once again, making it harder for predators to detect it. This color change also makes it harder for them to be seen by the prey that they are after. In the summer this coat gets much thinner than in the winter months. All of these changes contribute to the overall fitness of the fox in this particular environment.
This change in coat color and thickness arose by a process called Natural Selection, which is the process of decent with modification in which individuals in each generation differ slightly from the members of the preceding generation (Audersirk, Audersirk, & Byers, 2007). Basically the Red Fox population that migrated to arctic areas passed favorable traits (Traits that would help future generations thrive in the area) to their offspring. These favorable variations slowly continued mutating for several hundred-years until it created a whole new genus and species. The reason for this gene mutation was so that the fox was able to adapt to the environment. If these changes had not taken place, the fox may not have survived or thrived in that area. Eventually—because of this abiotic pressure—every individual in that population possessed this favorable trait; with many other generational changes taking place as well.
Audersirk, T., Audersirk, G., & Byers, B. E. (2007). Biology: Life on Earth with Physiology (8th ed.). Upper Saddle River, NJ: Pearson-Prentice Hall.
Nowak, R. M. (2004). Walker's Carnivores of the World. New York: The Johns Hopkins UP.
Planet Earth: Ice Worlds: Polar Bear and Cubs [Television series episode]. (n.d.).
Virginia Hayssen. (n.d.). In Clark Science Center - Smith College. Retrieved August 12, 2009, from http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/msigenus.html