No-one is saying that DNA literally alters itself. DNA is a molecule, a chemical, and as all chemicals is subject to chemical alterations. Chemical reactions can happen to DNA, and those chemical reactions changes the structure of the DNA molecule. Many of the types of chemical alterations that can happen to the DNA molecule are called mutations.
to look like something.
It is not the DNA that is altered to look like something, it the population of organism that harbors the DNA molecules in it’s member’s cells that is altered over generations, such that the individuals that make up that population come to appear differently.
And to suggest it survived and so the right direction was favoured is bogus.
No, it makes perfect sense. Genetic changes affect what the organism looks like because it’s genes encode the phenotypic attributes of the organism, including it’s appearance. So changes in those genes have the potential to alter the appearance so the organism comes to appear more like something in it’s environment.
Before it was this color and shape it obviously survived
It is not this organism itself that changed, it is ancestral populations that changed over generations. Individuals do not evolve, populations do.
and many not this colour or shape survived.
Yes, but they were less successful at it. Even very tiny differences in the ability to survive and reproduce add up over hundreds and thousands of generations. If individuals who carry mutation A survive better and have more offspring than those who don’t carry mutation A, then those differences will add up generation after generation. A larger and larger fraction of the population will be made up of those who carry mutation A. Eventually the entire population will be made up of carriers of A, and there will be none left who don’t have it.
There is no actual science behind such a claim.
Natural selection is an observed fact. It can even be implemented in artificial selection with selective breeding, as I’m sure most people have heard of.
its invoking some sort of magic nature pushing DNA one way or another.
There’s no reason to think this. Just look at selective breeding, there’s no “magic nature pushing DNA” involved and yet substantial morphological and color change can result from that.
IF Humans are the end of the food chain, everything survives, everything all the way up to us.
Obviously not everything survives. I’m sure you’ve seen those recordings of sea turtles hatching from their eggs and being picked off by predators on their hopeful run towards the ocean. If you’re a particularly slow turtle because you’re born with some sort of genetic defect, it will be more likely that some predator will manage to spot and catch you before you make it to the ocean. If you’re a particularly fast turtle, or better camouflaged, you have a greater chance than other turtles of making it. Not a guarantee, but a greater chance nevertheless.
Also there really is such a thing as competition for limited resources and mates in nature. It would be delusional to suggest otherwise. Some fail to reproduce and so leave no descendants(maybe they don’t find food, so do not survive to reproductive age), others succeed at having a few offspring, while still others are very successful and significantly out-reproduce their kin. Even for humans this is true, some have many more children than others. Some have none. Some die before they reach adulthood. This should all go without saying.
In fact, as we see, Fish, need not evolve, and did not evolve.
We do not, in fact, see that. Evidence shows that fish did actually evolve. I recommend Neil Shubin’s book Your Inner Fish.
They are still fish.
And those species of fish evolved from other species of fish before them, into the species of fish they are today. The fact that they are still “fish” does not mean no evolution took place.
In the same way that you are a mammal, that does not imply that no mammal ever evolves, nor does it mean the species of mammal you belong to did not evolve from other species of mammals that lived in the past. The fact that the species we are today, is still classified as a mammal, does not mean our species did not evolve. We did evolve, from other species of mammals before us.
The same is true for fish that live today. The fact that they are still classified as “fish” does not mean no evolution has taken place.
There is no need to walk out of the water.
There doesn’t have to be a “need” for it to occur anyway. It does not have to be necessary, nor to be needed, for it to be advantageous for individuals in some ancestral species of fish, to be born with mutations that make them very slightly better at living in shallow waters and survive for short periods outside of water. If there were insects living around shallow waters and near the shore, fish able to catch them and eat them would have an advantage over those that could not. They would be able to reach a source of food others could not. They would then be able to feed themselves, and survive, and have offspring that inherited those abilities.
Frogs also did not need to change, Nor did clams nor did thousands of other things. The Premise is wrong from the start.
The premise that things “need” to change is what is wrong. It’s not even clear what that really means.