ELI5: Why does evolution happen?

Evolution happens because living things with helpful traits are more likely to survive, have babies, and pass those good traits on to the next generation.

Imagine you and your friends are playing a game of hide-and-seek in a snowy, white backyard.

• If you wear a bright red winter coat, the seeker will spot you immediately.
• If your friend wears a pure white winter coat, they blend in and stay hidden for a long time.

In nature, this game is real life, and the rule is called natural selection.

• Babies are born slightly different: Just like you might have your mom's eyes or your dad's curly hair, animal babies are slightly different from their parents and each other. One rabbit might have slightly thicker fur, or one bird might have a slightly stronger beak.
• Life brings challenges: In everyday life, animals face tough conditions like cold weather, fast predators, or hard-to-reach food.
• Helpful traits win: An animal with a useful feature—like warmer fur in the winter—has an easier time staying alive.
• Passing it on: Because that animal survives, it gets to grow up and have babies, passing that warm-fur trait to its children.