I watched a video about a fish which became (the author theorized) transitional because this fish found that it could survive predation by swimming into shallow water where bigger fish could not follow. Presently, this fish grew apendages that assisted it to get even further out of the water and therefore escape more frequently. My question: Is there some recognition within the biology of the fish that "becomes aware" of this survival need of the fish and therefore supplies the means for better survival. I understand that mutation could provide these better equiped appendages to crawl out of the water but what is the signal for the organizm to know that it is this type of mutation that would help it survive?
... thanks