Kalissa's Blog

There are two forms of reproduction, sexual and asexual. Sexual reproduction requires much more energy invested than asexual reproduction but the variation it offers is significantly more advantageous than asexual. There are some particular concepts that display how advantageous sexual selection really is. First being The Red Queen Hypothesis, explaining that sexual selection only continues to exist because is allows organisms to continually adapt to their environment with other species evolving at the same time. This is in the context of predators, prey, and parasites. Up next is heterozygosity which occurs when there is more than one allele present in an organism. Lastly, Parasitism is an unexpected topic in sexual selection, but it has a different context than one may associate with sexual selection. The organisms reproducing, experienced variation and at some point that variation becomes more advantageous at combatting diseases like parasites. This challenges the thoughts I always ...

What is sexual selection and how is it related to natural selection? First, let us start off with defininf sexual selection. Sexual selection is when there are individuals in a species competeing for a mate, this can be genuine competitions or specific traits. Now, this is solely focused on attraction, not the ability to survive. However, you would hope that it would be related to both. Sexual selection relates to natural selection in a way such that these processes further evolution of traits in the populations. The focus of these differ. Natural selection leads to the organism's increased survival and their success at reproducing. Alternatively, sexual selection is a game of which organism has the favorable trait for potential mates. Why are the males of a species typically the ones on which sexual selection acts most obviously? There is a simple response, males invest more than females typically do in species. Sperm costs lest to produce, and species that have internal ferti...

What exactly is a species? Humans are obsessive with the categorization of the world around us. However, we often encounter that the world is not as easy to catergorize as one would expect. This is no different for how we group organisms as a species and their evolutionary relationships to one another. There are many systems that can be used for this, first being the biological species concept. The biological species concept is defined as a group of organisms that can naturally reproduce between each other and they are isolated from other populations. This provides a boundary based on reproductive isolation and explains how speciation occurs through gene flow interruption. This, however, does not explain asexual organisms, hybridization, or ring species. Next, is the morphological species concept where physical characteristics and phenotypes are take into consideration for defining a species. This concept can account for asexual organisms and can organize populations aside from genet...

This image displays the difference between Genetic Drift and Natural Selection. Genetic Drift is due to random chance where an even takes place to alter the allelic frequencies in a population. Alternatively, Natural Selection has more of a cause and effect behind it. In this instance, the brown rabbits do not blend into their environment as well as white bunnies. They fall victim to predation more frequenty leading to a shift in the bb allele frequency.

To understand what plasticity is and how to determine what makes a trait "plastic" is to start by defining the term. Plasticity is an organism's ability to change their phenotype as a response to an environmental condition change. With that established, there are many ways you can determine if a trait is plastic. First, you would have to uncover if there are any environmental conditions that would impact the organim's trait. Next, you could do a controlled experiment where you alter a specific condition to see if that changes the organism's traits or you could look at different species that are closely related or the same species in different environments to see if the trait is impacted by different environmental conditions. If that trait differs significantly between environments, then it would be considered plastic. This would then need to be compared to the genetic variation to determine that this is not due to genetic variation. If all of this leads to the con...

In selection, there are many aspects that play a roll beyond the genotype of the organism. In many cases, this relates to environmental factors pressuring organism's survival and reproduction. Those with traits better suited to their environment, like behaviors and physical characteristics, have a higher chance at surviving to produce offspring. Then, the genotypes associated with the better suited phenotypes are more likely to be passed on to offspring allowing the organisms in future generations to continue being selected for as long as external conditions continue to select for that trait. This pushes evolution foward. Use the dots in this as an example, the purple color is selected for (displayed by the higher number of offspring) due to the purple environment. The purple coloration allows them to blend into the purple environment better allowing them to continue to survive and reproduce.