Kevin, New Jersey asked:
Iíve been wondering about this question forever, I canít find the answer anywhere. How do living things know how to evolve? Letís take a seahorse, I donít know its name but it looks like a piece of weed in the ocean. How does the seahorse know to turn into that?
Itís not really a question of the animal knowing what to evolve into but this is a really beautiful example of evolution in action: mimicking the surroundings so animals are well-hidden and protected from predators. A particular species of seahorse will find a good bit of seaweed to actually hide amongst and gather food in a really nice place for it to live. As the seahorses breed and as new generations of seahorses are born small genetic mutations will change their appearance and change certain things about them. As their appearance changes you might get a mutation that makes them a slightly different colour thatís similar to the seaweed, for example. A seahorse thatís a very similar colour to the surrounding seaweed would be better protected because it would be camouflaged much better so hidden from predators. More of those colours, of course, would survive so eventually all of the seahorses would eventually resemble the habitat in which they live.
Other animals have evolved other ways to disguise themselves - with some disguises making them look poisonous, to put predators off.