Direct competition is resource intensive. Just to compete, species and companies have to invest heaps of energy in long trunks and roots, extra hunting and massive advertising campaigns for instance, instead of expanding or improving production. To avoid these costs they move into niches. Where there are multiple species or companies with very similar habits, one will eventually get an advantage somewhere and use it to get further ahead and outcompete the others. Consequently those that survive employ slightly different tactics and are spread between different habitats and markets. The fast food diverged from the fancy restaurants way back and nestled into more isolated markets. The fast food members have since emphasised their differences through differentiation of colourful plastic toys, varieties of hamburger and corporate identity, to appeal to different prey.

Companies can even evolve according to the prey’s preferences, their appendages growing beautiful but functionless layers of plastic and coloured cardboard, along with scents precisely attuned to attract passing shoppers.

All right, the mechanisms are half different (companies at least try to steer their behaviour, though I reckon natural selection comes in there to a great extent too). And the structure of the larger system is perhaps different (unless people are the decomposers, the production chain the trophic levels…yeah, whatev).