Question

Why do you think our visual system evolved to have its strenghts/weaknesses in processing light/dark environments? thinks of the conditions of the environments we evolved in and what we would have needed to survive in those environments...how did the mechanisms of our vision evolve to meet those needs?

Answer 1

Note: This response is in UK English, please paste the response to MS Word and you should be able to spot discrepancies easily. You may elaborate the answer based on personal views or your classwork if necessary.

(Answer) Our visual system has a few basic features. We are able to see in the light and have poor night vision, unlike bats. We do not have thermal vision like the Eagles but have good depth perception. Human eyes accommodate more colours in the spectrum than a dog and less than a butterfly.

Firstly, the issue with light is because humans never evolved to hunt at night. After they stopped being creatures that climbed, their prey consisted of land animals and not birds in trees. Most of these land animals that were hunted were also not nocturnal. Hence it would be difficult for humans to hunt at night. Furthermore, the lower temperatures at night would make it difficult for the human to carry out activities efficiently at night.

Secondly, humans do not have the same thermal insight that enables an eagle to know that a mole is hiding two inches below the snow. This might be because humans simply never needed to have this feature. Humans consumed animals that they later began to domesticate. There were not woodland creatures that were tiny and were adept at hiding in small crevices. Since humans foraged for larger animals, it wasn’t particularly necessary for sensing heat signatures of animals.

Thirdly, a normal human is able to decipher seven colours within the spectrum of light. Creatures like the butterfly and praying mantis are able to see thousands of more colours than a human being. Considering that both of these creatures are small insects who cannot particularly depend on nimble limbs, good hearing and evolved brains to manoeuvre and protect themselves from settling on a dangerous spot, they depend on their vision. Their vision that is highly intuned with colour helps them distinguish between safety and dangerous terrain. A human being, on the other hand, is able to touch, run, walk, see, hear etc. in order to decipher their environment, prey and even predators. This is why the humans did not evolve to have the same sight as butterflies.