3 ms·

The eye has been developed twice - check out cephalopod eyes. If anything, their design is superior (no blind spot, nerves on the rear vs front, hard lens vs so

The eye has been developed twice - check out cephalopod eyes. If anything, their design is superior (no blind spot, nerves on the rear vs front, hard lens vs soft deformable lens for focusing)

DangitBobby 5y ago
That's interesting. The Wikipedia entry [1] mentions that there's still debate about whether it's parallel evolution [2] or convergent evolution [3]. I'm very curious about why this comment got downvoted. 1.https://en.m.wikipedia.org/wiki/Cephalopod_eye https://en.m.wikipedia.org/wiki/Cephalopod_eye 2.https://en.m.wikipedia.org/wiki/Parallel_evolution https://en.m.wikipedia.org/wiki/Parallel_evolution > Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure. 3. https://en.m.wikipedia.org/wiki/Convergent_evolution https://en.m.wikipedia.org/wiki/Convergent_evolution > Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time.
- CRConrad 5y ago
  Those categories feel a bit arbitrary and overlapping: The difference between 2 and 3 seems to be whether there is a shared "similar original trait"... So, wouldn't every process of convergent evolution, where a similar trait arises independently in different species -- after a while automatically and inevitably have become parallel evolution, because after some time the once-new trait has of course become a pre-existing one? OK, OK, I'll go check on that debate... But given the quotes of the definitions you posted here, it sure seems pseudo-.
bewo001 5y ago
There are also compound eyes. The mantis shrimp's eyes cover a far larger part of the spectrum at better spectral resolution than our crummy vertebrate eyes. The can distinguish polarization and have some degree of depth perception within a single eye.

The eye has been developed twice - check out cephalopod eyes. If anything, their design is superior (no blind spot, nerves on the rear vs front, hard lens vs soft deformable lens for focusing)

DangitBobby 5y ago

That's interesting. The Wikipedia entry [1] mentions that there's still debate about whether it's parallel evolution [2] or convergent evolution [3]. I'm very curious about why this comment got downvoted. 1.https://en.m.wikipedia.org/wiki/Cephalopod_eye https://en.m.wikipedia.org/wiki/Cephalopod_eye 2.https://en.m.wikipedia.org/wiki/Parallel_evolution https://en.m.wikipedia.org/wiki/Parallel_evolution > Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure. 3. https://en.m.wikipedia.org/wiki/Convergent_evolution https://en.m.wikipedia.org/wiki/Convergent_evolution > Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time.

CRConrad 5y ago
Those categories feel a bit arbitrary and overlapping: The difference between 2 and 3 seems to be whether there is a shared "similar original trait"... So, wouldn't every process of convergent evolution, where a similar trait arises independently in different species -- after a while automatically and inevitably have become parallel evolution, because after some time the once-new trait has of course become a pre-existing one? OK, OK, I'll go check on that debate... But given the quotes of the definitions you posted here, it sure seems pseudo-.

bewo001 5y ago

There are also compound eyes. The mantis shrimp's eyes cover a far larger part of the spectrum at better spectral resolution than our crummy vertebrate eyes. The can distinguish polarization and have some degree of depth perception within a single eye.