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Old 03-01-2017, 07:00 PM
Irishman Irishman is offline
Join Date: Dec 1999
Location: Houston, TX, USA
Posts: 12,251
Originally Posted by adaher View Post
2) It does seem that some evolution is pretty predictable. For example, whatever senses a species needs most will become highly developed, while senses they need less will tend to stay primitive.
This is not by any inherent ability to predict what will be valuable for survival. Rather, the mechanism of natural selection works against the individuals that do not have traits that give them an advantage. The acquisition of those traits is by mutation.

For example, say rabbits have short ears. A rabbit is born with slightly longer ears. That rabbit can hear predators a bit earlier than his neighbors, and can therefore respond more quickly. He is more likely to survive and reproduce more. That trait builds up to long ears in rabbits, because the shorter eared rabbits get killed off more.

The traits that fit the environment get pushed by natural selection to improve, with the lesser versions disappearing by outcompetition. The traits that don't aid the environment don't improve. They might drift around, or even atrophy, but to improve it requires reproductive advantage.

Originally Posted by lazybratsche View Post
Proto-eyes are very useful, and found throughout the tree of life.
For example, some snakes (pit vipers) have pits on their face that are sensitive to infrared. Those pits are proto-eyes in the infrared spectrum. They give an sense and a bit of direction to that sense. They help the snakes detect body heat for finding prey.