Angelique's Evolution Blog

Fitness and Selection Absolute fitness is  the amount of offspring an organism produces over its entire lifetime. Whereas, relative fitness pertains to fitness of the other members of the population and compares an organism proportionately to the "most fit" organism in the population. Recall: fitness is one's reproductive success so the higher one's fitness is, the higher the amount of offspring they reproduce is. For example, the absolute fitness of a specific peacock (this fictional species has plumage and elaborate feathers in both sexes) named Jenny is 6 because she reproductively produced 4 peacocks in her lifetime. However, the relative fitness of Jenny is lower when compared to her sister Jenna who produced 5 peacocks in her lifetime. Positive selection is when an allele is favored by natural selection, which is any consistent difference in fitness among different classes of biological entities. For example, Jenna has a biological trait that affects her dermal...

Natural Selection Natural selection is defined as any consistent difference in fitness among different classes of biological entities (fitness meaning reproductive success). It is likely you have heard of the term "survival of the fittest" and probably in relation to the concept of natural selection. The usage of the term "the fitness" often implies one has the most physical strength, but it does not necessarily allude to the true definition of fitness in natural selection: reproductive success. Let's visually explore the difference from being "the fittest" versus "good enough" and how it relates to natural selection below: Thanks for reading!

 Convergence, Natural Selection, 'Survival of the Fittest' Convergent evolution is the evolutionary relationship that occurs when organisms that are not closely related evolve similar traits or behaviors. Whereas, divergent evolution is the opposite of convergent evolution and occurs when two organisms share a common ancestor and evolve one or more traits and behaviors that make them different from each other. I have chosen the following example from "Improbable Destinies" to illustrate convergent evolution: different caffeine-producing plants. Using DNA comparisons, the author of this book built an evolutionary tree illustrating how coffee, tea, and cacao all occur on different branches of the phylogenetic tree. They are not closely related to one another. Coffee, tea, and cacao all convergently evolved due to them not being closely related based on genetic research but evolved similar traits or behaviors (in this case, caffeine production) as seen in the figure belo...

 Mutation and the Tree of Life It is helpful to view mutations as any change in the DNA sequence of a cell! In the following depiction below, I illustrate a simplified example of different types of mutations (substitution, deletion, and insertion) using geometric patterns as a model for a cell's DNA sequence.  Now let's step away from viewing mutations through a geometric point of view as seen above and turn to look at the role of mutations in organisms, specifically in cocomonteres (a fictional organism)! As depicted above, the cocomonteres' exposure to parasites ultimately led to a mutation that caused a deformity, specifically an increase in their amount of limbs. A similar tragedy can be found with  Ribeiroia ondatrae in amphibians in the Western United States of America ( see here for more interesting information on the topic ). Based on the information given above, do you believe their mutation was beneficial, harmful, and neutral? In the case of growing excessive l...