What Doesn’t Kill Us Makes Us Stronger

Who would’ve thought that viruses, out of all things, have actually played a large role in who we are today?

Darwin’s Surprise suggests that viruses have helped humans and other species evolve many of their advantageous traits that exist today. For example, the placenta, a very important organ that nourishes the fetus during mammalian pregnancy, may have been proliferated due to a virus that targeted offspring inside of eggs. The species who laid eggs had less reproductive success while the species with placentas were able to reproduce and thus that trait was passed on. As Heidmann said, “It is quite possible that, without them [viruses], human beings would still be laying eggs”. Additionally, some viruses may have genetic material that fends off other viruses from infecting its host. It is thought that humans may have dormant viruses hidden in their DNA that are helping us fight against other dangerous viruses. These dormant viruses are being passed on through generations as long as they prove to be advantageous.

As a retrovirus evolves, the host may adapt, and these adaptations are passed on. This idea definitely changed what I thought about viruses. I never really thought about viruses as something that we actually needed in order to evolve. I always considered them as the enemy. That’s how most people view viruses when they first learn about them in grade school biology. We learn that they are dangerous, fast-evolving, sometimes under the radar, killing machines. All of that can be true, but we also must regard them just as we might regard any other natural occurrence that has caused evolution. Viruses, predators, natural disasters, environmental changes, etc. all can play a part in the evolution of certain species. At first, they could seem like negative things. However, they have all been at play since the beginning of time and continue to occur in order to create stronger species.

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This entry was posted in AP Biology, Evolution, Viruses. Bookmark the permalink.

One Response to What Doesn’t Kill Us Makes Us Stronger

  1. henrym says:

    You mentioned how retroviruses may evolve, and as a result, the host will likely adapt. What I immediately thought of was coevolution, the process by which two species evolve based on interactions between the two. A traditional example would be between a pollinator such as a honeybee and a flower. This relationship is mutualistic because the bee benefits from the flower’s nectar, and the flower sees increased pollination and reproduction rates. But what about a parasitic relationship? Evolution as a result of viral infection is not a one way street, despite the exclusive, one-sided nature of a parasitic relationship. I would be curious to see how changes have been imposed on both organisms over time. We retain viral DNA, which may or may not help us, but where do these viruses go? How have endogenous viruses fueled our evolution, and how have we fueled theirs?

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