Fitness
A lot of times people take the term fitness to mean someone who is in good physical shape. The same goes for the term "survival of the fittest". People take this to mean that the stronger, faster, etc. will out live the weaker organisms in a society. However, this is not the case for evolutionary fitness. Evolutionary fitness is an organisms ability to survive, reproduce, and pass on traits that give them an evolutionary advantage. Fitness means more than just being physical strong or fast, it's about being best suited for the environment you are living in. An example that comes to mind when thinking about fitness is the evolution of Sickle Cell Anemia.
Sickle Cell Anemia is a heritable disease that causes misshapen red blood cells. This disease can be very deadly. However, it has actual evolved to an advantage for people living in areas with Malaria. Being a carrier of Sickle Cell Anemia holds greater fitness in places with malaria because the sickle cell trait actually provides resistance to malaria. The trait allows individuals to survive and reproduce. They then pass the trait on to their offsprings. This is just one example of how fitness doesn't always mean being physically better than other individuals in the population. It's about being able to adapt and survive the environment you inhabit. Now being able to measure fitness is pretty complicated. There are many variables that must be considered when trying to measure fitness. To measure fitness you need to be able to track a specific heritable trait through multiple generations. You need to be able to track the survival rate of individuals with and without the trait. You would then need to see how the trait is passed on to offspring and if the frequency of the trait changes as generations go on.
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Great conclusions about "the survival of the fittest" not necessarly being the strongest or fastest. Something like a weed could have higher fitness than something like a giant tree depending on the environment! Nice job!
ReplyDeleteThis is the example that I also used when defining fitness! Something I am curious about is invasive species and their fitness relative to a nonnatural habitat.
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