but the main problem i have with evolution is the start...evidence of adaption i accept...but how did it start from nothing...as simply put in laymans terms please...god always existing as a counter argument is not good enough reasoning
Cool, this is a great place to start. This is a good example of what evolution *isn't*, since it doesn't try to explain how life originated. It's hard to nail down what exactly life is, but if we assume there is some line that gets crossed where a lump of stuff isn't alive, and then we add some property to it (reproduction is a likely one) and call it life, then that's where it started. There are theories about how that point got reached, but evolution picks up after that point.
So there's the first point. Evolution doesn't address the question of "how did life start?" Only, "How did the different species of life come to exist?"
Once life was already rolling, how did it become all the different species? Evolution says that life needs to continue (survive) and reproduce. So whatever qualities the creature has to enable it to do that are "good" and anything that gets in the way of that is "bad". Mutations occur (cosmic rays altering the DNA?), giving the creature's children some new trait, probably a bad one. A frog with an extra leg sticking out of his side, for instance. That creature will not survive as well as his peers, and his mutated genes will die with him. But sometimes just at random a change takes place that's a good thing. Maybe the frog's tendons attach a little higher or lower on his legs, giving him a better jumping ability to escape predators. Because he can escape when others can't, he'll survive longer. He'll have more offspring that also carry his better jumping genes. If there's any sort of pressure in his environment (lots of predators) he and his children will be the ones that survive, pretty soon taking over the population. Now they ALL have better legs, and the not-so-good legged ones have to either die off, or find a less predator-rich environment to live in. (Let's assume they moved)
(Note here that mutations occur at random, but the "good" ones are selected as keepers by virute of the fact that they are being carried by the creature most likely to survive and reproduce. Mutation is random, selection is not.)
That explains how a frog might become a better frog, but how could a frog ever become something else, something not a frog?
The trick is to realize that tiny changes add up. A frog with better legs can hop clear out of the water. While he's out, he can snap up food on the sides of the pond that other frogs can't reach. Once all the frogs can do that, the ones that can see better can be even more successful. And the ones that manage to get the ability to detect sounds will do better still. A frog that can ultimately live completely out of the water might be able to survive better still. And since he's out of the water, being covered with a fuzz would prevent him from getting sunburned. If that fuzz was thicker, he'd even survive better when it gets cold. And if the coloration on his fur made him attractive to females, he'd reproduce more.
Go back to the weaker frogs that moved away from the predators. They live in the water, they don't see well, they can't hear (for purposes of this illustration), they are furless. Compare them with the frog that has stronger hind legs, better eyes, hearing, and a fur-like coat. Is he a frog anymore? If so, how much more do we need to change before he isn't a frog?
It's a slow process and hard to get your head around. But it is also an inevitable process, one that when you really examine it you find MUST happen. Just like a dropped rock must fall to the ground, DNA-based creatures that reproduce MUST evolve. It's natural.
Dave
