While it's true that "mother nature" is often invoked as a sentient being, and hence "mother nature knows" would not raise any eyebrows, "biology knows" sounds distinctly odd to me. This is one suggestion which would sound more natural, but others might come up with something even better.

I think we are more accustomed to this phrase, implicating that some things are beyond our rational thoughts.

The corrected version. Thank you Marie-Hélène!

quite simply, the author is personifying biology, as if to say 'biology is well aware that it can use variability and mutations'. It's a strange collocation, but works fine, especially if the author is being ironic or cutting, which seems likely here

I agree with the idea of 'biology encompasses' in this context. 'Biology knows' sounds like a literal traslation of the German phrase 'Die Biologie kennt X', which may exist in Russian as well and which generally means that X is closely associated with biology or is an attribute or feature of biology.

Although it is possible to use 'know' in a personalised construction such as 'biology knows', it normally has the sense of 'recognises', and it is often used in a negative construction (e.g. 'literature knows no limits to personal expression').