Selection is constantly at work, grinding away to create the fittest individual, so why does its job never end? Why is selection constantly at work? The answer is genetic variation. This can occur through mutations and gene flow. Mutations arise and if beneficial stay, adding something new to the genetic environment, bringing diversity and variation. Gene flow allows new genetic combinations to form. Think of it as wanting to make the best dinner possible. With any good meal you have a lot of flavor, a lot of spice. The world uses genes like spices. You throw in a little pit of this, a pinch of that and BOOM! an amazing species fit for the environment has arisen. Yes, it might be a little bit more complicated than that, but it shows us that different genes/spices can bring something new.
Just like you would expect this creates an endless cycle. New genes somehow someway enter in to the population, either through a mutation, genetic drift, etc., and selection makes the decision on wether or not to work and keep that gene. Then before you know it another new gene arises and the whole process starts all over again. Evolution is always changing, it never rest, or says that something is good enough. Evolution is a head chef always trying to make the best dish.
Hi Mary,
ReplyDeleteVery well said! Your blog explained exactly why genetic variation cannot be eroded overtime. Also awesome job of comparing this to cooking a meal!
Great blog post Mary! I also talked about mutations and gene flow. I agree with your thought process, even if a species increases fitness of one time of gene, there will always be mutations in other aspect of their genetic code which provides variety.
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