Turtles start off their lives on the beach, and as they are amphibians, they must find their way into the water. Every once in a while, a turtle that has a slight genetic variation will make it to the water because of it's better traits. These traits will be passed down to the next generation because instead of dying like the rest, this one will survive to reproduce.
Survival and reproduction
Over production is an important part of the natural cycle. If you don't produce enough children, then after the death of so many, there may not be enough left to pass on the desired trait that you had, making it impossible for the next generation to get that gene. Even if one offspring does survive and mate, that doesn't mean that it'll have ALL the desired traits you had.
Just like humans moving on from their fears, there is no moving forward without competition. If competition were not a thing, then there would be no reason for evolution, and we'd be the same forever.
If a turtle survives all the way throughout it's adult years, then it will return to the place of it's birth and mate and have it's own children, which will then carry on it's traits and do the same things that it's parent(s) did, but on it's own, not through teaching, but through instinct.