Variability hypothesis

The variability hypothesis is the idea that there are more differences between individuals of the same species than there are differences between different species.

Imagine you and your teddy bear are both mice. Even though you look similar, there are lots of differences between you. You might be a different size or have different fur colors. Your teddy bear might have a different shape or texture than another teddy bear. These differences are examples of variability.

Now imagine you and the dog across the street are different species. You might look very different from the dog, but all dogs of the same breed look pretty similar to each other. This means there is less variability between different dog breeds than there is between individual mice.

Scientists use the variability hypothesis to explain why there is so much diversity within a species. It helps them understand how evolution works and how new species can form over time.