People create biodiversity

Here is an example:

[T]he Collaborative Cross, an ambitious project to create hundreds more mouse varieties representing a wider range of genetic diversity, is beginning to deliver its first animals. The new mouse strains have some very visible differences from one another — from variations in fur colour to tail length — and are already yielding clues to genes that help fend off fungal infection, which might not have been easily uncovered with standard lab strains.