living things can change or modify the abiotic environment in the ecosystem over time.

Yeppur--think of the effect of lichens on rocks--over time and generations the rocks are broken down into soils changing the environmental niche and providing a footing for grasses.

Rap

And the biggie: over the course of a billion or so years, cyanobacteria took in CO2 and excreted oxygen as their waste product, and eventually flipped the world over to an atmosphere containing comparatively large amounts of free oxygen (which is extremely reactive and doesn't stay around for long unless it's continually replenished), which a couple billion years later enabled us to evolve