Convergence, Natural Selection, "Survival of the Fittest"

 Convergence, Natural Selection, "Survival of Fittest"

From the reading in the book "Improbable Destinies" I learned that the eyeball of octopi and humans are nearly identical. Convergent evolution is when two or more distinct species share a similar trait, and do not have a common ancestor. Divergent evolution, on the other hand is where species with a common ancestor descend and develop unique traits independently. An example of this would be a dog and a wolf, or birds and bats having wings. The eyeball of the octopus and human would be an example of convergent evolution as their most common ancestor "swam the Earth more than 550 million years ago" and had no eyes. Despite octopi having 8 tentacles, living underwater, being able to change their skin pigmentation and contract their bodies to extremely small sizes, (being an entirely different species) their eyes are shockingly similar to ours, having a lens, pupil retina and iris. Both eyes also focus light onto their retina to form an image. 

These two distantly related organisms evolved to develop convergent features through the process of natural selection. Throughout time, mutations occurred in both humans and octopi. These mutations could have beneficial, harmful, or neutral to the survival and reproduction of the species. For example, an octopus could have developed a mutation that limits the movement of their eyes. If there were another octopus present that had greater eye movement, they would be more likely to survive, as it would have greater peripheral vision and be better suited to spot predators. Having greater awareness of predators, they would be more likely to survive, and therefore reproduce. The octopus with the eyes that allow for increased survival would stay alive, while the octopus lacking peripheral vision would die off. This is an example showing how traits that are better suited for the animals survival, will stay within a species, while poor traits will not. There are many reasons why humans and octopi could have convergently evolved similar eyes, but a strong suggestion is that our environments and needs required similar visual standards, causing similar evolution. Both the human and octopi might have benefitted from concentrating light onto the retina as there was an abundance of light for both species. There are many examples of what could have caused such evolution, but the best conclusion I can come to is that both species had similar needs when it came to their ability to visualize and interact with their environments. 

Comments

  1. AngeliqueSeptember 19, 2024 at 5:48 PM

    The nearly identical nature of both our's and octopi eyeballs is an eery fact for sure. Your illustration of both and inclusion of other evolutionary examples are superb! Great job Gracie.

    ReplyDelete
  2. Abby DeckerSeptember 19, 2024 at 6:29 PM

    It is crazy that we have a similar eye to an octopus, I wrote about the same example! Your drawing is amazing keep up the good work!

    ReplyDelete
  3. JodieSeptember 20, 2024 at 1:10 PM

    Solid discussion of convergent evolution. Nice illustration demonstrating shared features between the human and octopus eye. - Dr. W

    ReplyDelete
  4. KelleySeptember 20, 2024 at 2:53 PM

    Hi Gracie! I thought your definition of convergent evolution was great and enjoyed your example of how human and octopus eyes are similar! I also loved your drawing!

    ReplyDelete

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