Evolution Spring 2021

We can see in the pipefish example that the female has striking colors, helping her to court the male. Normally, we see the male exhibiting these fancy displays in order to attract the females. This is because the females have eggs, which are seen as far more valuable than what the male has to offer. The most obvious example I can think of is peacocks and their exuberant fans. This female pipefish is displaying her coloring in order to attract a rather boring-looking male, which is extremely unique.  In Microphis deocata (pipefish), it is actually the male that carries the fertilized egg, not the female. This could explain why the female is required to have such a display; she needs to attract a male that will carry the fertilized egg for her. The males, in this case, have more value than the females. Therefore, they are sought after by females. My hypothesis is that female courtship arose due to the fact that the females in this species need a male to carry the fertilized offsprin...

This blog post is allowing me to dig deep into my current and past knowledge of evolutionary forces. Looking back on what I have learned so far, I can apply some concepts to this question of why genetic variation is not eroded over time due to selection.  Although selection may eliminate genetic variation, we will still see mutations occurs in an organisms genome. Just because selection eliminates some, doesn't mean more won't arise. This can be due to environmental factors, or simply mistakes made during DNA replication. A wide array of things can cause genetic variation, so just because selection "eliminates" the variation, is not to say that it will not continue to occur through these processes.  We can also see that selection is not the only force that acts on genetic variation. Say selection did eliminate variation, we will can still see gene flow and genetic drift occur and introduce variation into individuals and therefore the population. Selection is not alway...

The neutral theory of evolution states that evolutionary changes at the molecular level are due to random genetic drift of selectively neutral nucleotide substitutions (Tong, Ranganathan, 2013). The mutations that occur under the neutral theory are the result of genetic drift. We can see these mutations become fixed over many, many generations. Although they are neutral mutations, they are able to be fixed due to genetic drift. Kimura's theory really differs from the original theory of natural selection due to the fact that Kimura's theory emphasized that these are random mutations. We also do not see much about fitness or environmental influences in Kimura's theory of neutral evolution. I believe that this basically contradicts the whole theory of evolution by natural selection, where the most fit individuals survive and reproduce as a result of having advantageous genes. The key differences are that Kimura's theory relies on random genetic mutations and lack of select...

What are some benefits of inbreeding that may lead to the evolution of assortative mating? What are some of the costs of inbreeding that may have prompted to evolution of inbreeding avoidance (disassortative mating)? Inbreeding can be seen in a few species, such as Mangrove Killfish, some plants, and endangered species. Inbreeding can lead to assortative mating, where individuals with similar genotypes mate to produce offspring. I could see this as being potentially beneficial if the traits that the individuals have are favorable, and allow the species to survive and thrive in the environment they're in. Assortative mating can evolve as more and more individuals are produced from inbreeding, therefore the offspring simply do not have anyone else to mate with, since all the possible mates have similar genotypes. We can see inbreeding in endangered species, which in turn could continue to produce that species and help fight endangerment. But, it's not a given that these offspring...

I n your blog, write about how you interpret the observed phenotype distributions in the context of the one-island model of migration? Also, if you had to summarize the evolutionary consequences of migration for populations, what would you say? We can see with the one-island model, that on the mainlands we mainly see phenotype D, which is a striped color on the snakes in order for them to blend in with the leafy floor and environment for better survival. If snakes coming from the islands, who have phenotype A (solid gray coloring), come to the mainlands, it really does not affect the phenotype distribution. When we look at the one-island model, it shows us that migration from the continent to and island has HUGE impacts on the phenotype distribution. But, if individuals come from the island to the mainland, it really makes a minor change in the phenotype distribution. Ontario and the Peninsular Mainland are very strongly favored for Phenotype D, while the other three graphs are mostly ...