Evolution 2021

How long does it take for new species to form?   Do you think the speed of speciation varies among different modes of speciation?   Look for evidence to support your conclusions! I think it the length of time for a new species to form would vary for each species. It would also depend on  how you define speciation. In the class textbook, there's at least 10 different definitions of what a species is in different contexts. I've been exposed to the  Biological Species Concept (A species is a group of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups) the most, so I'd say I'm most familiar with this definition.  I do think the speed of speciation varies among different modes of speciation (and by modes of speciation I think they're specifically referring  to  allopatric and sympatric speciation?) It's harder to tell if sympatric speciation has occurred compared to allopatric s...

With your knowledge of sexual selection theory, can you formulate a hypothesis that explains why female courtship might have evolved in this species? Is there anything about pipefish biology that might support your hypothesis? With my knowledge of sexual selection, I know that typically females have the choosers bias when it comes to courtship. This is because, most commonly, females invest more time and energy than the males when it comes to reproduction. The females can afford to picky, while the males can't. The males are trying to reproduce as much as possible, while females have to invest more time and energy to carry the fertilized eggs and eventually give birth. Because females invest so much, they have high standards when it comes time to pick a mate. Even then, some mothers continue to raise the offspring up until a certain point. While it does occur in some cases, males are not typically the ones to help raise the offspring. Males typically invest a small amount of time a...

The objective of this reflection is to pick a trait or an organism that has always fascinated you. What adaptations does it have? How have scientists tested adaptive hypotheses? Lithobates sylvaticus (Wood frogs) have always fascinated me. These frogs have adapted to cold climates by freezing over the winter. When temperatures begin to drop, wood frogs store urea and convert glycogen to glucose. This produces a special antifreeze substance that prevents ice from freezing within their cells. These molecules help prevent the frogs cells from dehydrating while its body tissues freeze. During this time, they stop breathing, their hearts stop beating, and their blood stops flowing. They can endure freezing temperatures for months. Not only is this completely wild, but these frogs have always reminded me of that episode from Avatar: The Last Airbender (when Aang had to find frozen frogs for his friends who were sick). The only cure for their illness were these frozen frogs. Fine spatial scal...

Selection is often assumed to eliminate genetic variation. So, why is genetic variation then not eroded over time? Based on what you have learned in the past modules, from the basic mechanisms of evolution to quantitative genetics, reflect on the diversity of mechanisms that can explain why genetic variation is maintained in populations. - Based on what we've learned so far, genetic variation is maintained in populations because without genetic variation, a population would not be able to evolve to fit its changing environme nt. The presence of genetic variation implies that individuals of the population vary in the alleles they possess, meaning that individuals differ in genotype. Genetic variation allows natural selection to increase or decrease the frequency of alleles already in the population. Selection does not drive alleles to fixation. Phenotypic variation can either arise from genetic variation and/or environmental variation. Only the differences that arise from genetic va...

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 real breakthroughs or changes in your understanding? - As far as breakthroughs go, I definitely am more confident in my coding skills and overall computer skills now that I've been introduced to R-Studio. Beyond that, I think my understanding what evolution is and how is behaves have definitely changed for the better. Before this semester began, I had a very limited understanding of what evolution truly is, and I think that's how it is for a lot of people, especially those outside the science community. That's probably where a lot misconceptions about evolution stem from.  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? - In my original blog post, I defined evolution as "... a concept that proposes all life forms diverged from one common anc...

Inbreeding is a common phenomenon in natural populations.  What are some benefits of inbreeding that may lead to the evolution of assortative mating?  -  Inbreeding is the mating or breeding of individuals that are closely and genetically related. Inbreeding is an example of self-fertilization, which typically results in specific genotypes. Assortative mating occurs when organisms determine their mates based on genotypes and phenotypes that are similar to their own.  I nbreeding can promote adaptation and may act as an exit strategy for some endangered species.  The benefits of inbreeding may have led to the evolution of assortative mating. In a scenario where two related organisms both exhibit desirable traits within a population and mate, their offspring could potentially obtain those same desirable traits. What are some of the costs of inbreeding that may have prompted to evolution of inbreeding avoidance (disassortative mating)? - There are much more costs ...