Why do our eyes look so different to that of a birds or a crabs or even other mammals? Is it due to them being used for different things? Or is it to do with the position of them in our head or something?
In: Biology
Evolution mostly.
We came from primates.
We are predator more than prey so we have forward facing eyes.
We see color because color gives us an advantage when gathering or scavenging. Bright colored things can be poisonous but some fruits are better when brightly colored.
Our eyes dilate when dark so we can see in the dark and narrow so we can see in daylight. Humans are naturally marathon runners. Humans can actually outrun every animal on the planet because nothing else has our stamina. We could outrun cheetah or horses if chasing them assuming we can keep track of where they went. So seeing day and night was a huge advantage.
Since it’s evolution, generally if it didn’t have a negative it was passed on. Colorblindness is a negative today, but it could have made hunting easier and thus stays in the gene pool.
Our eyes have more sclera (the white part) visible than most other mammals because we’re almost entirely active during the day, so we don’t need our pupils to get big enough to let in a whole lot of dim light. Other more crepuscular animals like dogs will have larger pupils to allow them to see in low light, while animals with slitted pupils are often nocturnal to allow higher regulation of light. Different types of pupils give different advantages to the animal as well as where the eye is placed and how much the animal relies on sight as opposed to other senses.
Hi 🙂
With circular pupils you get a crisp image, from an optical standpoint.
With longer, horizontal pupils, you can see approaching predators better.
With longer, vertical pupils, you get a mix of more light as they can get bigger, some better perception of depth… Especially when sneaking low to the ground. Ideal for hunting 🙂
Also see https://www.youtube.com/watch?v=5pij1OE1uPM <3 Curiosity show
There was a husky down the street when I was a kid with the exact same shade of blue eyes as I have. Cats have different eye technology, to improve their hunting at night, but other mammals have pretty similar eyes to humans. Crabs are a much older form of life, and their eyes are very different inside.
The question is, what type of animal?
Compare a humans eye to that of a dog or gorilla, and superficially they look very similar.
Compare them to the eyes of a cat or goat, and you have something very different.
The trick is that different species have evolved to use their eyes in different ways, so they have ended up with eyes that are specialised to suit the jobs that specific species needs. Some will be better tuned for night vision, for sharpness, for maneuverability or field of view,, and these will all come with different physical properties and changes that affect the way they look.
So a dog has fairly human like eyes because they do a similar job, a cat has eyes better suited to night vision with better control over the pupil to allow this, while a hamster wontnrely on their vision so much and will have more basic eyes.
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