Evolution Extravaganza

 Across the animal kingdom there is a vast array of species that exhibit unique aspects of dimorphism in which the male of a given species will often possess external traits that are far more colorful, patterned, etc. than the female. Examples of these incredible displays of dimorphism range from peacock's massive fans full of vibrant colors, to mandrills (a monkey species) and their bright noses. This dimorphism that exists across the animal kingdom is attributed to sexual selection due to Bateman's principle in which female eggs are far more valuable and less plentiful than ejaculates from males. However, a unique example of dimorphism is present in the pipefish species, Microphis deocata as the female actually is the partner who exhibits prominent displays of color and patterns to woo the far more dull male Microphis deocata.  Without further research this unique reversal of roles seems almost as if it is an evolutionary error that arose, but the true answer is quite the op...

Selection is one of the most pertinent and driving factors of evolution that we have discussed thus far in the semester. Pinning down an exact definition or cause of selection is quite difficult as it is so diverse in its actions across every species, but the key aspect of selection is that it typically decreases genetic diversity in a population due to a multitude of factors. This is due to selection in natural populations causing certain genetic aspects to offer organisms a higher fitness and these individuals will likely reproduce and thrive better than their lower fitness counterparts that belong to the same population. However, we do not observe populations genetic variation becoming stagnant in any natural population, even if an organism obtains a highly advantageous relative fitness level due to genetic mutations. Why? Specifically, why does selection not yield a significant decrease in genetic variation in a given population, even if this population maintains a perceived apex l...

 The typical and most prominent theory of evolution is based on the ideas of natural selection. However, in 1968 Dr. Kimura proposed an alternative theory of evolution that differs significantly from the evolution theory based on natural selection. Kimura's theory is known as the neutral theory in which the driving factor for evolution is attributed to random genetic drift. Specifically, this neutral theory of evolution is maintained at the molecular level involving random mutations in DNA that may not contribute to a phenotype specifically, but over a multitude of generations, these neutral mutations may actually become fixed in a population due to genetic drift. This theory clearly deviates from the theory based on natural selection as Kimura's theory focuses on aspects of genetic mutations that are far more difficult to study and far more random than the more accepted theory of evolution based on natural selection. In addition to this, a significant difference is that Kimura...

 Inbreeding is an interesting topic in nature for a multitude of reasons. While I was aware that inbreeding and non-random mating alter the Hardy-Weinberg equations, I was not aware that inbreeding does not actually influence evolution itself. After learning that inbreeding causes an increased number of homozygotes in a given population, I now realize how it directly affects HWE, while not affecting the population's evolutionary path because of non-random mating. I also had always presumed inbreeding hindered nearly every population of organisms that partook in it, but this too I found my reasoning to be errored in. After pondering and researching how inbreeding may actually improve a population, I found an article titled "The Costs and Benefits of Inbreeding" from The Institute of Canine Biology. This article discussed both the benefits and disadvantages that may arise from inbreeding. The most prominent benefits that may actually arise from inbreeding or non-random mati...

 The one-island model of migration maintains that a far larger population inhabiting a spacious area will significantly influence the allelic distribution of a nearby smaller population that resides in an area both minuscule in comparison and diverse in it's environment. This model relies on the migration of some organisms from the larger population to the smaller populations place of inhabitance. This type of migration will have a far greater impact on the small population than it would if some organisms from the small population migrated to the area where the larger population resides. While this description may seem confusing at first, I will utilize an example of water snakes in Lake Erie to better convey how this type of migration occurs. In Lake Erie there are two unique populations of water snakes possessing different phenotypes based on their environment and ability to camouflage. The first population of water snakes reside on the mainland and they often exhibit a striped p...

 Since there is no specific question for this week's blog post, I will discuss an animal fact that I find particularly intriguing. If you were to answer the question, how high do you think a squirrel can fall from and live? 10 feet? 100 feet? 200 feet? Actually, any numerical answer you give will actually be wrong which is what makes this fact so interesting. Squirrels terminal velocity, that is meaning the fastest speed a squirrel is capable of reaching from a free fall, is not fast enough to generate a force strong enough to cause the squirrel's death. While a squirrel might be injured from a 20,000 foot drop, it will still survive. This unique aspect likely arose through adaptions as squirrels are obviously great climbers and spend a significant portion of their time above ground. The explanation for why a squirrel will not perish from a massive free fall stems from both their light weight and anti-aerodynamic build. Squirrels have a large bushy tail and a broad body when ou...