Intro to Frog Evolution, Biological Communities, and Species Interactions

With all these different types of frogs found around the world, frogs have also evolved and adapted to their environment. As frogs reproduce, their offspring carry specific traits and the cycle continues until some sort of disruption occurs in their ecosystem. When a disruption occurs, such as the introduction of new species, climate change, or depletion of water resources, natural selection becomes crucial in the survival of the frog species. Natural selection is "the process of better-selected individuals passing their traits to the next generation" (Cunningham & Cunningham, 2012). This could be a reason why some frogs are immune to the chytrid disease and why others are infected and many specific populations are becoming extinct.

Another type of evolution in the world of nature is called coevolution. Coevolution is the "response of predator to prey and vice versa, over tens of thousands of years, produces physical and behavioral changes in a process" (Cunningham & Cunningham, 2012). Some frogs that are vibrant in color are not physically appealing because they want to attract the female frogs, it is because their color can camouflage them in their habitat or remind other prey that these colors mean danger and the skin can be poisonous. The different external skin pattern of every frog helps them survive from natural predators.

G.E. Hutchinson, a limnologist, proclaims that "every species...exists within a range of physical and chemical conditions (temperature, light levels, acidity, humidity, salinity, etc.)" (Cunningham & Cunningham, 2012). The statement from Hutchinson means that frogs have also adapted to their surroundings. Frogs live in almost every area of the world except Antarctica (Frog, 2008). As frogs emerged from the water thousands of years ago and wondered onto the land, their body changed. Frogs now had limbs to navigate on the ground, lungs and skin have adapted to breath in the air as well as losing their need for a tail (Biller, Stempect & Chase, 1997). 

As these glorious amphibians are evolving and adapting to their world, there also exists something called tolerance limits. Victor Shelford, an Ecologist, explains that "each environmental factor has both minimum and maximum levels" (Cunningham & Cunningham, 2012). When frogs are unable to reproduce in areas away from water, their chances of survival greatly decline. There are specific living conditions that frogs require in order to thrive and moisture is a key component. If a frog inhabited an area where chytrid was found in the water, their respiratory system would be under attack and moisture could not get into their fragile bodies.

 

Sources:

 Biller, S., Stempect, B., & Chase, J. (1997). The frogs of new england. Retrieved from http://library.thinkquest.org/11034/index.htm 
 

Cunningham, W., & Cunningham, M. A. (2012). Environmental science a global concern. (12 ed., pp. 74-95). New York, New York: McGraw-Hill.
 

"Frog"  22 April 2008.  AnimalPlanet.com. <http://animals.howstuffworks.com/amphibians/frog-info.htm>  17 September 2012.