Some questions...
- Do you agree that if you have a group of animals - say a herd of zebra - then each individual will be slightly different to the others?
- Do you agree that some of those differences can make it easier for that individual to survive - say, better eyesight so it has a better chance of spotting an approaching predator?
- Do you agree that these differences are due to the genes that the animals have?
- Do you agree that the genes that are responsible for these differences can be passed on to the offspring when that animal reproduces?
- Do you agree that if an animal has some genes that mean it has a difference that helps it survive, this animal is more likely to have more offspring precisely because these differences help it live longer (living longer means more chances to reproduce)?
- Do you agree that if animals with these helpful differences produce more offspring, then the number of animals in the herd that have this helpful difference will tend to increase over the generations?
- Do you agree that if we wait for enough generations to pass, most if not all animals in the herd will have this difference, and what was once different is now normal?