As nature is a necessary but not a sufficient condition for biodiversity, I do not investigate: Why is nature as such ethically valuable? But: Why is diverse nature ethically valuable? First, I show that biological diversity will eventually have an indirect value, if nature is valuable, and that this is too little. Then I argue against an argument which defends the aesthetic value of biodiversity. After that I shortly defend the medical value of biodiversity. In the main part I argue that biodiversity – except in some parts – has a value because it supports freedom.