Rin's Evolution Blog

     Absolute fitness is the total number of offspring one produces over its lifetime. Relative fitness, on the other hand, compares the absolute fitness of one to the average fitness of the complete population. While the absolute fitness of the organism stays the same, as the average changes, so does its relative fitness. We can observe this by looking at a population of butterflies.       Let's say we have two butterflies, one white and one brown. The brown butterfly will produce 40 offspring in its lifetime, so it has a relative fitness of 40. The white butterfly will produce only 30, giving it a relative fitness of 30. The average of this population is 35, so using the equation for relative fitness, we can see that the white butterfly has 1.14, while the brown butterfly has 0.86.      Using this same population of white and brown butterflies we can explore positive selection on the trait of wing coloration. We will assume that this p...

     When we think of natural selection, our mind usually goes to the belief in "survival of the fittest" as described by Charles Darwin. However, it is not always the fittest organisms in a population that pass their genes down to their children. The concept of "survival of the good enough" is actually a more accurate descriptor when it comes to natural selection. When it comes to finding a mate and reproducing, an organism doesn't need to be at the absolute top of its population, it just needs to be good enough to survive and reproduce. If an environment changes and results in a subsection of the population becoming better suited despite not necessarily being the 'fittest', they are simply good enough for the new environment and will continue to pass on their genes to the future population.       Additionally, in competitive species, the top of the population in terms of strength and fitness is constantly expending extra energy to maintain its alpha ...

       Convergent evolution is when two species that are unrelated evolve similar traits, structures, or features. However, these are analogous structures. This means that while they are similar in function, the structure is different and independently evolved in each species. This may lead one to believe that these species are closely related and share a common ancestor, but this is not always the case. There is also convergent evolution, which is different from divergent evolution as it is when multiple species with a common ancestor evolve homologous structures.        An example of evolution through convergence can be seen in whales. Before whales were recognized as mammals, people assumed they were a type of fish due to the similar structures of fins and flippers. We now know that these structures were due to convergent evolution. These shared structures most likely came about through natural selection and the shared selection pressure o...

     DNA is a molecule containing genetic code and can be found inside the cells of every organism. This code contains pairs of bases and determines how an organism will develop and function. During replication, when the DNA is trying to elongate itself, mutations can occur. In the picture below, you can see an example of a mutation, where a base pair of TA turns into another CG pair. This specific type of mutation is called a transversion, but there are many other ways the genetic sequence can change.       Mutations can be large or small, and can even impact the survivability of an organism. To see an example of this we can look at the species Vulpes catticus. This species lives in an environment that frequently gets snow, so when a mutation occurs that results in the organism having white fur, it is beneficial to the organism's survival. As it can better blend in with its surroundings during the snowy months, it is more likely to survive to mating s...

     One evolutionary misconception I used to hold when I was younger was that humans had stopped evolving. I was interested in looking into this myth to help show others just how prevalent evolution is, even in complex and advanced creatures such as humans. I used to believe that our technological and medical advancements caused us to no longer need to evolve. However, this is simply a myth, as evolution is a slow process that takes many generations to become visible. Organisms that reproduce quicker show the effects of evolution much faster than we do as humans, since we have a much longer life span. For example, a bacteria that only lives for a day will reproduce much quicker, resulting in many generations in just a week. This results in quick evident genetic changes that cannot be seen in humans. Every organism is constantly evolving, and there is no way to halt that process.       A somewhat recent evolutionary change we can see in humans to prove...