Fitness
I define fitness as how well an organism is adapted to its environment in order to be able to survive and reproduce. If an organism is "more fit" than another, this means that it has a higher likelihood to survive and reproduce, and its offspring will do the same. This organism that has high fitness has genotypes/phenotypes that are selected for within their environment. This means that the individual does not necessarily have to be the biggest, fastest, etc. but it has traits that allow it to successfully live long enough to reproduce and have its traits passed on to the next generation.
A classic example of this is brown vs green beetles fitness. If a species of beetles has both green and brown beetles living in it, yet they live in a wooded and dark area, the brown beetles would have a higher level of fitness. More of the green beetles would stand out against a dark background and would likely be preyed upon more than the brown beetles who are camouflaged within the trees. The brown beetles would be considered more fit than the green beetles since they have the trait that will help them to survive and reproduce more than the green beetles. This could lead to evolution, eventually the trait for being green could become less and less prevalent within the population and eventually disappear. This shows how natural selection affects the evolution of a species.
On the other hand, if the beetles lived in a green, leafy area then the green beetles would have a higher level of fitness and would be able to survive and reproduce at a higher rate than brown beetles. This shows how natural selection is highly dependent upon the environment that the species lives in, and this determines which traits are advantageous. Quantifying this fitness would be done by observing the rates at which specific phenotypic traits are passed on to offspring. These phenotypic traits that are directly a result of the organism's genotype are those which will be passed on through generations and allow of this fitness to be passed on.
image from: http://www.dynamicscience.com.au/tester/solutions1/biology/evolution/naturalslctn.html
Hi Ashley
ReplyDeleteGreat job. I just have a question for clarification: based on your definition, when you quantify fitness, is it a measure of an individual, a population, a species?
Cheers, Michi
Hi Ashley,
ReplyDeleteI really enjoyed your example, using beetles to educate other on fitness is a nice way to do it. Also, with how well you explained yourself here you can essentially take most of this post and follow up on it to complete the 3.2 post!
Hi Ashley,
ReplyDeleteI thought you did a great job explaining the term fitness. I like how you included that individuals do not necessarily be the biggest or the strongest, but rather based on their own enviroment. I also liked the example you used over the green and brown beetles. Great job!