Allison's evolution blog

An organism that I have always been fascinated by is the great white shark. Don't get it twisted though, while I am fascinated I have always been scared of having an encounter when in the ocean. I have always been fascinated by these amazing creatures because of their size and power. Great white sharks usually grow to be an average of 15 feet long and 2.5 tons or greater. The really big great whites can even grow to be as long as 20 feet!! That's insane. Great white sharks mouths are lined with 300 serated, triangular teeth which are lined up in several rows. They even have organs that can detect electromagnetic fields generated by animals. Great white sharks have some amazing adaptations as well. Great whites boys have adapted into a torpedo shape in order to reduce the drag in the water. Great whites also have a fairly symmetrical body, and this is thought to allow them to move through what at a more efficient rate. Sources: https://oceantracks.org/library/spe...

Selection is often assumed to eliminate genetic variation. So, why is genetic variation then not eroded over time? Genetic variation has not eroded over time because there are many different factors that affect it other than selection. We have learned about a lot of different ways that genetic variation is maintained in class from the past few modules. For example, quantitative traits which are controlled by multiple traits and the environment. Not all quantitative traits are normally distributed because one trait may be dominant and the other may not be. Another factor that affects genetic variation is drift. If there is strong genetic drift, this will lead to small populations, and this swamps out selection. Genetic drift is very different than selection because it does not lead to adaptation unlike selection which increases the average fitness across populations. There is also a major difference in the selection on dominant vs. Recessive traits. Dominant alleles reap advantages righ...

So far I have learned so much in evolution class, and I have also really enjoyed the layout of this class. I have learned that I really enjoy the discussions in small groups because it helps me to better understand the topics.   I went back to my first blog post where I defined evolution, and I said that "evolution as a change over time in a species". I went into more details with what this meant to me and gave examples as well. Since the post, I have learned so much more about what evolution is and I would change my initial response by adding more details of other factors involved in evolution. I learned that the modern perception in evolution takes more factors into consideration such as how important the environment is to causing differences in fitness. The differences in fitness can then lead to change in the generations to follow. I would also add in that mutation is the main cause of variation that can cause evolutionary change. Evolution can be very small or very large...