5 ms·

Even as someone fully accepting of evolutionary theory, this diagram felt like a revelation: http://i58.servimg.com/u/f58/17/30/76/23/evolut10.jpg http://i58.se

by aggie 11y ago

Even as someone fully accepting of evolutionary theory, this diagram felt like a revelation: http://i58.servimg.com/u/f58/17/30/76/23/evolut10.jpg http://i58.servimg.com/u/f58/17/30/76/23/evolut10.jpg

fiatjaf 11y ago
I don't understand what is the good from passing from 1 to 2 or 2 to 3.
- tamana 11y ago
  More light collection and higher resolution of details
- InclinedPlane 11y ago
  From 1 to 2 you get directionality. 2 to 3 improves directionality a great deal (it's basically a continuum from depression to pinhole eye).
- PhasmaFelis 11y ago
  In 1, light from any direction will fall on all the pigment cells equally. Essentially, your camera only has a single pixel--you can't tell direction at all, only degree of brightness. In 2, light centered on the cup will fall on all the cells, but light from the side will be occluded by the edge of the cup and only fall on one side. Now you have a low-resolution camera, and can roughly tell which direction light is coming from. In 3, light from any angle will only light up a small part of the cup's interior, allowing for greater precision--effectively, higher resolution.
fiatjaf 11y ago
The mutation from 4 to 5 is enourmous.
- Dylan16807 11y ago
  It is, but it's easy to imagine the continuum in your head. The lens getting sharper, getting muscles to shift it, the cornea getting clearer... Seeing how you go from nothing to spot to pinhole lens eye is the critical part.
- trhway 11y ago
  i wonder about the evolution from 5 to 6 (along the lines of https://en.wikipedia.org/wiki/Geordi_La_Forge https://en.wikipedia.org/wiki/Geordi_La_Forge)
- InclinedPlane 11y ago
  It's not a single step, it's just one sign post on a long highway (you can't show all of them). Every step along the way is pretty straightforward and immediately useful. Eyes are an interesting example, because they are seemingly incredibly complex systems, yet eyes have evolved independently dozens of times. For example, octopuses and humans have equivalently complex eyes which have entirely different origins and have slight differences (for example, human eyes have a blind spot due to the nerve fibers being on top of instead of behind the light receptors).
DrScump 11y ago
Did the original accompanying text say that each step was a single mutation, or is this just general evolution of sight?
nimbs 11y ago
Better: https://upload.wikimedia.org/wikipedia/commons/b/b6/Diagram_of_eye_evolution.svg https://upload.wikimedia.org/wikipedia/commons/b/b6/Diagram_...
- emmelaich 11y ago
  I prefer @aggie's because it refers to actual species.
  - emmelaich 11y ago
    Also the use of words like "developed" in the text of the second is unfortunate.
CaptSpify 11y ago
I can't find the clip, but cosmos has a great segment on this. Here's a non-animated view: https://www.youtube.com/watch?v=SHgHI8YnsF8&feature=youtu.be&t=89 https://www.youtube.com/watch?v=SHgHI8YnsF8&feature=youtu.be... Basically, they go through each of those stages, and shows what it would look like from the creatures point of view

by aggie 11y ago

fiatjaf 11y ago

I don't understand what is the good from passing from 1 to 2 or 2 to 3.

tamana 11y ago
More light collection and higher resolution of details
InclinedPlane 11y ago
From 1 to 2 you get directionality. 2 to 3 improves directionality a great deal (it's basically a continuum from depression to pinhole eye).
PhasmaFelis 11y ago
In 1, light from any direction will fall on all the pigment cells equally. Essentially, your camera only has a single pixel--you can't tell direction at all, only degree of brightness. In 2, light centered on the cup will fall on all the cells, but light from the side will be occluded by the edge of the cup and only fall on one side. Now you have a low-resolution camera, and can roughly tell which direction light is coming from. In 3, light from any angle will only light up a small part of the cup's interior, allowing for greater precision--effectively, higher resolution.

fiatjaf 11y ago

The mutation from 4 to 5 is enourmous.

Dylan16807 11y ago
It is, but it's easy to imagine the continuum in your head. The lens getting sharper, getting muscles to shift it, the cornea getting clearer... Seeing how you go from nothing to spot to pinhole lens eye is the critical part.
trhway 11y ago
i wonder about the evolution from 5 to 6 (along the lines of https://en.wikipedia.org/wiki/Geordi_La_Forge https://en.wikipedia.org/wiki/Geordi_La_Forge)
InclinedPlane 11y ago
It's not a single step, it's just one sign post on a long highway (you can't show all of them). Every step along the way is pretty straightforward and immediately useful. Eyes are an interesting example, because they are seemingly incredibly complex systems, yet eyes have evolved independently dozens of times. For example, octopuses and humans have equivalently complex eyes which have entirely different origins and have slight differences (for example, human eyes have a blind spot due to the nerve fibers being on top of instead of behind the light receptors).

DrScump 11y ago

Did the original accompanying text say that each step was a single mutation, or is this just general evolution of sight?

nimbs 11y ago

Better: https://upload.wikimedia.org/wikipedia/commons/b/b6/Diagram_of_eye_evolution.svg https://upload.wikimedia.org/wikipedia/commons/b/b6/Diagram_...

emmelaich 11y ago
I prefer @aggie's because it refers to actual species.
- emmelaich 11y ago
  Also the use of words like "developed" in the text of the second is unfortunate.

CaptSpify 11y ago

I can't find the clip, but cosmos has a great segment on this. Here's a non-animated view: https://www.youtube.com/watch?v=SHgHI8YnsF8&feature=youtu.be&t=89 https://www.youtube.com/watch?v=SHgHI8YnsF8&feature=youtu.be... Basically, they go through each of those stages, and shows what it would look like from the creatures point of view