I love this topic, junebug. Thanks for giving us another chance to talk about it! You don't have to understand evolution to benefit from it every day. If you have ever had a flu shot or a blood transfusion or were tested for allergies, or have eaten corn, or had a vaccination, you have benefited from the theory of evolution. Police solve crimes using DNA--that is based on the theory of evolution.
The basics of evolution are not that hard. All life came from a common ancestor, and the closer species are to each other, the more characteristics they share. You see it all around you-- most kids look kind of like their parents, closely related species can have offspring (lions and tigers are both a type of cat, and can have offspring--ligers!) while species that are very far apart cannot (dogs and cats, or birds and snakes, can never have offspring).
Humans, gorillas and chimps are all primates who share a common lemur-like ancestor. The three are too distantly related to have offspring, but are close enough to have similar characteristics in appearance and social organization-- and even to share diseases.
All of that supports the theory of evolution. If distantly related species like cats and lizards could have offspring, that would mean the theory was false. If kids routinely looked nothing like their parents, that would mean the theory was false. Imagine how strange it would be if two dachshunds mated and produced a litter of poodles, black labs and collies. There would be no way to breed animals with any kind of certainty.
It is a mistake to think that an individual animal or plant or insect "decides" to evolve. It is not about individual choice. Otherwise humans would have "decided" to evolve wings so we could fly. It is about what makes it possible for an organism to survive long enough to reproduce and pass on its characteristics to its offspring.
And it is not always about being the meanest, fastest, biggest or smartest. Plants evolve to resist pesticides, repel insects, survive drought or cold. Some animals are not fast or strong, but they taste bad, or look like they might taste bad. Turtles are not fast, but they have evolved hard shells to protect themselves. Lots of weak animals are small so they can burrow and hide from predators. One bee can't survive very well alone, but in groups they do very well. Humans have no protective claws or fur, but have big brains to invent tools and make clothes. Whales are mammals evolved from land animals and now can live in water. We know this because, unlike fish, whales still have foot bones, give birth to live young and nurse them with milk.
The discovery of genes reinforced the theory of evolution by showing exactly how similarities pass from parent to offspring. Genetics is about as much proof as science needs that evolution is true. Anytime a person says that "x runs in my family", or looks for a certain breed of dog that is good with children, they are accepting that genetics is real, and they are also accepting the theory of evolution.
These are scientific facts and have nothing to do with "denying a creator". No creator has been detected by science--yet. If there is one, it is very good at hiding from people, even those desperately looking, for thousands of years.