Quote:
Originally Posted by questor
There is no question that evolution exists. There are questions that have not been answered.
Did sea creatures NEED to move onto land and therefore develop legs?
Why didn't the ones left in the sea have the same NEED? The environment was the same.
Did some species of dinosuar NEED to develop wings and become a bird? ....
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questor,
When you ask questions about "NEED", you are automatically assuming that the critter's DNA feels or experiences a "NEED". Or Evolution itself experiences a "NEED". You are assuming that there is some Driving Force that pushes the critter's evolution in one direction or another.
That assumption is unnecessary. There doesn't have to be any "NEED". In fact, Evolution as a theory (explanation) works a lot better if you discard "NEED" altogether.
The best way to answer your questions is to recognize that the questions are flawed.
Why one critter moved onto the land, and not its near-relative cousin, may be the result of many possible factors:
The one critter was exposed to shallower water and bigger tides than its cousin.
The one critter's food source grew better at the water's edge; its cousin fed off food that grew better in deeper water.
The one critter had fangy predators that patroled all but the shallowest water.
The one critter had fins that could mutate into bony fins with a single codon mutation; its cousin did not.
The one critter wound up living near the mouth of a river, and the lower salt content evolved its metabolism over time, enabling its skin and lungs to withstand longer exposure to dry air; its cousin lived near the shore in normal salt water.
and on and on... These are the kinds of random things that determined how any particular critter evolved, not "need" or "want" or "drive".
Evolution is blind.
