Critique of Judgement by Immanuel Kant Chapter 82 Page 7

Linnaeus go the apparently opposite way and say: The herbivorous animals are there to moderate the luxurious growth of the vegetable kingdom, by which many of its species are choked. The carnivora are to set bounds to the voracity of the herbivora. Finally man, by his pursuit of these and his diminution of their numbers, preserves a certain equilibrium between the producing and the destructive powers of nature. And so man, although in a certain reference he might be esteemed a purpose, yet in another has only the rank of a means.

If an objective purposiveness in the variety of the genera of creatures and their external relations to one another, as purposively constructed beings, be made a principle, then it is conformable to Reason to conceive in these relations a certain organisation and a system of all natural kingdoms according to final causes.