What is co-evolution?

Co-evolution is when two things change together over time, helping each other out like best friends.

Imagine you have a favorite toy, let’s say it's a teddy bear that loves to play catch with you every day. One day, the teddy bear gets bigger and stronger, so it can throw farther. You notice this and start practicing harder, so you can catch even the farthest throws. Now you are better at catching, and the teddy bear is better at throwing, they both got better because of each other!

This is kind of like what happens with animals and plants in nature. For example, a bird might eat berries from a bush. Over time, the bird gets better at picking berries, so it eats more of them, and that helps the bush grow stronger, because the bird spreads its seeds farther. The bird and the bush are like your toy bear and you: they help each other change and get better together!

So co-evolution is just two things growing stronger or changing together, helping each other out every step of the way.