Darwin had 5 predictions in relation to his idea of descent with modification. In this post, I hope to explore and mention some evidence that supports his prediction that species change through time (also known as microevolution). Microevolution is characterized by a change in the frequency of traits to be passed down to following generations in a population within a short time. To support this idea, I will be continuing with a study about a freshwater crustacean known as the Daphnia obtusa.
Published from the University of South Carolina on November 20th, 2015, the study explored if a larger eye size and reproduction were linked. An overview of the article can be found from EurekAlert! here . In summary, the study found that there was statistically significant evidence showing that larger eye size is correlated with about one more egg created than usual. With this study, their goal was to find more subtle differences in ocular evolutionary changes compared to the more macro example of cave fish, which they achieved. Connecting the study with microevolution, the Daphnia obtusa with larger eye size were able to pass down the trait of having a large eye compared to having a small eye because they were able to produce more descendants. And this is only one example on how microevolution works, so there are still more to be discovered and researched!
Oh man, this is so cool! I only have one question: why do you think Daphnia with larger eyes produced more offspring? To proliferate a trait, individuals with said trait must have an advantage over individuals without it. Do you think natural selection favored the larger eyes, or increased numbers of offspring? Basically, which trait is favored, and why might they be connected?
ReplyDeleteI'm not looking for a "right" or "wrong" answer - just throwing out some interesting questions to gnaw on! I don't know the answer myself, tbh. But this is a really cool case study, so great job finding it!
Were there any possible biases in the study? Did the study raise any other questions?
ReplyDeleteThe correlation between eye size and number of eggs was interesting! Was this article helpful in understanding the most recent R assignment (with the cave mollies)?
ReplyDeleteHi Bridgett. I know I am late to the party but I enjoyed reading your blog post. I thought you made sense of the article you provided (which was a cool read) and did well applying it to Darwin's idea of descent with modification.
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