4 ms·
You could have 2 - 4 for other sensory cells, like heat or touch, and then be a single mutation away from sensing light. Iirc, some snakes have some heat sensi
by procaryote 2y ago
You could have 2 - 4 for other sensory cells, like heat or touch, and then be a single mutation away from sensing light.
Iirc, some snakes have some heat sensing cells arranged in pits to give them a directional heat sense. If you did that with visible light instead of IR those pits would be what halfway to an eye would look like
- wolfhumble 2y ago> sensory cells, like heat or touch Like light sensitive cells these would need a similar 1 - 4 +++, so the point would really be the same.
- procaryote 2y agoNot at all... If the question is "how could an eye evolve" it's reasonable to start from a baseline of a complex organism that has sensory cells but lack eyes or even light sensitive sensory cells. A cell sensing light can use the same type of nerves etc as other sensory cells, so there is no need to explain how a cell sensing light + a nerve + a central nervous system evolves in one step. If you wonder how a nerve could evolve for example, that is a different question. If you have two cells and they can exchange chemical signals, which is useful in itself, you have the start of a nerve.