Evolution Spring 2021

  What have you learned so far? Not in the sense of what did we cover in class, but where have you personally have had some breakthroughs or changes in your understanding? If you go back to your original blog post where you defined evolution, how would you change it? How has your understanding of evolution changed since then? What concepts are you still struggling with? Where do you think you need additional help and clarification? Now that you have studied some of the basic concepts, what are you curious about? What are the things you are wanting to learn more about? So far in this class, I have realized that I had some misconceptions about evolutionary processes. I was able to see how natural selection can drive evolution, but does not necessarily cause it. This along with some other foundational concepts have been able to be cleared up by this class. I also find enjoyment in writing these blog posts ungraded- it allows me to express my thoughts (whether right or wrong) in a...

Do you think mutation rates evolve? Explain your answer in the context of Darwin's postulates about natural selection! Under what circumstances do you envision high or low mutation rates to be adaptive? I personally think mutation rates can evolve. A species can undergo mutation quicker or slower than previous encounters with mutation, depending on the demand from the environment. I think The environment plays a huge role in this; if the environment is not favorable, then the species will quickly evolve to be better suited for that environment, as opposed to if the environment is mostly favorable and requires little mutation/evolution. I also think that if mutation occurs and it is favorable, it will continue to mutate and produce more individuals with these traits. Darwin also points out that individuals within a species are variable, so one individual could undergo a mutation more often than other individuals due to natural selection. This would make the mutation rate evolve over...

For this blog post, we are going to be thinking about natural selection and how it relates (or doesn't!) to evolutionary changes in a species or population. Natural selection allows individuals to survive and reproduce because they have favorable traits that allow their survival. Now, this will mostly allow survival of the favorable individuals, but it won't necessarily make the population evolve. There will still be diversity in the population. Not every species will physically change just so they survive better, some will just have a higher chance of survival. Evolution can occur due to natural selection, but it won't always.   I found a great article explaining this concept. Fisher states,  " under the idealized conditions of a constant environment, natural selection increases the growth rate of a population, but that, in practice, environmental deterioration owing to physical and biotic changes, including increased population density, has the opposite effect, such ...

Fitness is the survival of a species within a population. Relative fitness is the survival of a specific gene throughout generations. I believe that fitness represents natural selection at play and those with the most favorable traits will survive. Of course, the environment has a huge impact on which species or traits survive and I think this is an important concept to consider.  To calculate fitness, I would choose a species to investigate. Let's say I want to measure the fitness of brown beetles over a period of five years. I would collect a sample of beetles (wherever they are prevalent) and then determine how many have a specific phenotype/genotype I am looking for (in this case - a brown back). Then, maybe in six months or a year, I would go back to that location and collect the same size sample of beetles. This would allow me to see how many have reproduced and passed on the favorable phenotype of having a brown back, which would enhance their survival because they blend in ...

 Lamarck had several good points in his argument, but there were several points I could not help but question. I agree that if animals do not use certain body parts, they may become nonfunctional. Now, that's not to say they will "shrink" and eventually be non-existent. For humans, we have evolved to not need our appendix and although we do not need it, it does not grow smaller and smaller over each successive generation. It has simply just become nonfunctional. This also applies to the statement about the giraffe necks; yes they might grow a bit longer over time, but not due to "nervous fluid" flowing through or because the trees are taller. Giraffes are born with a long neck and it grows proportionally to their bodies to allow them to reach food in the trees.  I do very much agree that organisms adapt to their surroundings and that nature drove them to become more complex. That is a very true statement. But, I do not believe that life began through spontaneous...

 In this week's blog post, I am going to unveil why I think species change throughout time (microevolution).  This is one of Darwin's ideas of descent with modification and I have found substantial evidence to prove this.  I decided to research hedgehog evolution, because with everything going on with the stock market and the hedge funds... this is what came to mind. I found an interesting article about hedgehogs in Central Europe. Bolfíková and Hulva state in this article that       "many examples of these patterns were found in Central Europe because this region is a crossroad of postglacial colonization routes for many terrestrial species due to Pleistocene climatic oscillation in European biota" (Hewitt, 2004). While that is a mouthful to say, it is essentially trying to telling us that species are undergoing microevolution due to the crossing of species at this specific location. Hedgehogs are insectivores, and they were severely affected by the a...