C. Gatschet - BIOL 520

The idea that mutation rates can evolve shatters the predisposition that mutations are entirely random. However, environmental factors can certainly act on the evolution of mutations and their frequency throughout a population. According to Lynch et al., the evolution of mutation rates depends on three main factors: first, the production rate of a deleterious mutation in a population, second, the reduction in fitness of each mutation, and third, the heritablity or persistence of that mutation through generations (2016). Consider a scenario where a natural disaster randomly wipes out a significant amount of a species' population. Through this event of genetic drift, we can imagine that the variation and mutation frequency in the species would be fairly high; thus, this has become a perfect population for selection to act on. As selection acts against the force of genetic drift, the mutation rate will decrease until an equilibrium is reached over time. This is displayed by the red an...

Fitness's definition certainly has the connotation of being physically in shape, strong, or able to endure long periods of strenuous activity. However, biological fitness is more defined by an organism's or species' reproductive success, which is determined through how well adapted the organism is to its environment. Before fitness though, there must be variation in a population allowing the mechanism of natural selection, and thus fitness, to occur. According to  Sedeer el-Showk, fitness can be measured by comparing the ratio of a specific genotype before and after selection, or simply by measuring change over a long period of time where there is some sort of major environmental change (2014). A prime example of fitness is the order Crocodilia, a practically unchanged species since the Jurassic era. In a study by Stockdale and Benton, the body size of crocodiles was measured and compared against major environmental changes such as the Cretaceous–Palaeogene extinction perio...

Derivation from a Common Ancestor: Homologous Evolution of Biofluorescence in Sharks [Fun fact: I actually made a Canva for this, but my links didn't transfer over :( and I wasn't about to re-copy+paste everything. So if you'd rather view the graphic (without links), you can find it  >here<  .] Taking a dive into the depths of the ocean, the water becomes continuously bluer and darker as red wavelengths from the sun are filtered out. In order to combat the increasing darkness, biofluorescence among marine life is widely expressed across taxa - more than 180 species of fish! (Sparks et al., 2014) . Not to be equated with bioluminescence where light is self-generated by a series of chemical reactions, biofluorescence occurs when green fluorescent proteins (GFPs) along with brominated tryptophan-kynurenine metabolites absorb filtered blue UV light from the sun and re-emit lower energy green light (Park et al., 2019) . A more detailed description of the mechanism of bi...

Evolution is the result of a combination of several mechanisms which eventually contribute to changes in the genomes of a species. The most compelling and perhaps most well-known mechanism for evolution is natural selection in which certain mutations are "selected" for by the environment. Random traits are either beneficial or deleterious and eventually, the most advantageous traits will be passed down through generations eventually becoming more common in a population. Other key mechanisms include macro and microevolution, genetic drift, speciation, and notably, mutation. It's important to consider the significance of the environment and its role in interacting with mutations to drive evolution as a whole. Lastly, genetics, the figurative blueprint of life, is at the very core of evolution. The smallest alteration in a nucleotide or sequence has the potential to change the evolutionary course of an entire species. Prior to Tuesday's discussion, I would have had the p...