Natural Selection & Evolution- Module 3.2

 

    One major component of evolution is heritability. It is the ratio of variation based on individual phenotypes which will later be passed on to the offspring. Natural selection is just the mechanism behind evolution that is impacted by differing factors such as resource availability, competition, and reproduction. In some changes, the product of natural selection can be evolution, but heritability must be present. The differences amongst the phenotypes must be observable. If there is a trait that gets favored based on the principles of natural selection and it does not become heritable, then it would not be considered evolution. It is possible that an organism has adapted to a factor for only a certain amount of time.

    For example, let’s consider the activity of hibernation. During hibernation, animals decrease their heart rate and slow down metabolism to conserve energy for the cold winter. This is a temporary state based on a change in the environment. If the winter was not as cold with higher temperatures then regular, then the animal most likely would not need to hibernate. They would be able to stay active since hibernation is based on suitable environmental conditions. In this situation, hibernation is an adaptation. The trait for the ability of hibernation may have been obtained from evolution, but I don’t think that the act of participating in hibernation itself is evolution- just more of a temporary adaptation.

    I was unsure of exactly what the question of how selection might happen in the absence of natural selection was asking and how to answer it. I’m not sure if this is correct, but I thought about organisms choosing mates. Mating selection could be behavioral which can be based off environmental adaptations and personal want. Even though selection is present, it is not necessarily based on natural selection. They choose mates based on personal choices whether it includes the coloring or sounds of the potential mate.

Comments

  1. John Coffin (TA)February 22, 2021 at 10:21 AM

    The differences between phenotypes don't need to be observable to US, they just must be able to be "seen" by selection. Natural selection could lead to the evolution of biochemical pathways that increase the efficiency of uptake of some resource (maybe sugars in bacteria). While we can't "see" that adaptation, natural selection likely can.

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