Man's changes are abrupt and discrete. We are not outside of nature but we rock the boat pretty hard.

Is my post or the parent somehow committing this fallacy? I explicitly used the same verb for genetic modification on behalf of both subjects: man and nature. The distinction between the subjects is because bacteria and insects ('nature') will devour all of humankind's nutritional resources if people don't continually labor to prevent it. It's a speciesist distinction, but not a fallacious one.

I don't think it is reasonable to assume anything but heat death will win the resource battle in this universe.

Technically it's not a fallacy it's a premise, though a debatable one. These things are fundamentally different, if even just by the definition of nature and man and given that we don't fully understand natures mechanisms ourselves. I agree though, generalizing our own engineering is bad because it isn't "natural" is easily refutable.

I will suggest this though, nature has been out-engineering nature for eons longer than we have, so if you want to get technical it gets the benefit of the doubt here. Our own tinkering has yielded incredible boons and shouldn't be quickly dismissed but we can't ignore the potential dangers and the history of global risk human greed and power seems willing to incur to get what it wants. That's all.

Also reading the grandparent, I don't think his point was that man can't out engineer nature, but that there is a heavy risk inherent in Monsanto's corporate strategy of trying to creating super breeds and monopolize markets with them to the exclusion of diversity (note this is generally considered bad for the market not just nature, call diversity a natural law if you will). So both child comments are arguing for and against a straw man, which, again if you want to be technical about things, is a fallacy.

Full disclosure: I love me some heirloom vegetables from my farm share (dirty hippy I know!)