Joanne's Blog for BIOL 520

Honestly, I am not sure, but here is my best guess by analyzing each of the postulated. Darwin had the following postulates regarding natural selections, which is the context in which we will ponder the evolution of mutation rates.  The first postulate is that there tends to be an excess of offspring.  The second postulate is that not all offspring can survive.  The third postulate is the the offspring are variable, meaning their survivability differs. The fourth postulate is that parents can pass on their traits to their offspring (heritability) The fifth postulate is that those who have favorable characteristics will survive.       The first postulate is the excess of the offspring, which, when examined alone does not give much information regarding the evolution of mutation rates. But when considered with the second postulate, it would make sense that this competition for resources would impact how the organisms survive, therefore those with mutatio...

I definitely didn't realize how many moving parts and misunderstandings that I had about evolution. I suppose I shouldn't have counted on the wisdom of high school and introductory biology classes to define fitness or natural selection correctly, but to each their own. I feel like even talking about basic things like fact vs theory or realizing that not all natural selections lead to evolution caused me to realize that this class is going to teach me a lot more than I realized.  Going back to the first blog post, as I mentioned, I think that realizing that not all natural selection has to lead to evolution was different. I think I get a bit hazy with the terms in general, but once we were given a visual, such as we did with fitness, I understood what is trying to be said more.  I am definitely still struggling with the R Studio, but I think with more practice it will come more naturally. Once someone explains it to me, I feel a bit dumb because quite often the solution is simp...

When thinking about evolution and natural selection, often those two terms come to mind in tandem. However, as we discussed a few weeks ago, natural selection does not necessarily lead to an evolutionary change. Natural selection is how an organism with one variation of a trait tends to leave more offspring in the next generation than organisms that are lacking that more specific trait. Natural selection occurs without evolution when there are differences between individuals that are not genetically based.  For natural selection and evolution to occur, the trait must be heritable or must be genetically based. If that is not met, then there will not be evolution. Say person Y found person X really attractive because they had a really nice bright white smile with nice straight teeth. However, person X got their teeth whitened and had worn braces all throughout their young adult life. Person X had gotten their crooked yellow teeth fixed because they thought that they would be deemed m...

Much like others have mentioned, the idea of "fitness" in the world of science seems to conjure up thoughts of ripped bodies and enduring stamina. However, under the scope of evolution, fitness carries a bit of a different meaning. In concise terms, I would define it as the ability of an organism to reproduce AND survive. An organism would have good fitness if they are able to reproduce many offspring that are able to survive. This would mean that there were be a higher chance that the genetic traits of the organism could be passed on to the next generation. Thus, poor fitness would be lacking either of those parts. If an organism is able to have many offspring and almost none of them survive, or if the organism has offspring survive but it's a low number, then there would be low fitness as there isn't a high chance that the organism would be able to pass on their traits. To measure fitness, an experiment would need to be done that focuses on a singular trait so that ...

Lamarck theorized that organisms would change due to their environment. He believed that when these organisms had induced these changes, the changes would be more advantageous to them. Thus, they would be able to better survive and would therefore pass on these traits.  Lamarck had a fairly close base theory to adaptation and natural selection in this aspect.   His notable example to support this theory was through the use of a giraffe. Lamarck believed that the development of the giraffe's neck occurred when the giraffes switched from low to high branches. As the giraffes stretched their necks to reach higher branches, through the inheritance of acquired characteristics, this allowed the giraffes to pass down down their elongated neck down to their offspring. Lamarck's theory also seemed to hinge on the thought that organisms were able to "will" itself to change and adapt. The active participation principle is where Lamarck went awry and his theory began to become un...

 What I prediction I chose to base my example around was species changing through time (microevolution). The example I chose was the evolution of MRSA. I think this example is interesting as it bears a similarity as to why researchers are anticipating COVID-19 to evolve. MRSA can be a good example of microevolution as one dominant strain, healthcare associated MRSA (HA-MRSA) type ST239, has been evolving locally at hospitals and reaching global proportions as it gains antibiotic resistance. Now, why specifically is it this strain that is important? The reason why this strain is integral is in part due to its environment. Hospitals often are able to have access to higher-end treatments, such as antibiotics. The frequent usage of antibiotics, especially in cases of over-prescription or unfinished treatment, gives bacteria an opportunity to adapt. As a result, HA-MRSA is able to evolve at a rapid pace due to an increased exposure to antibiotics than it would encounter in most environm...