How does erosion affect the earth's surface?

Answer 1

It gives it most of its topography - but over the Earth's life is also responsible for allowing terrestrial life to develop.

Without erosion the basic "shape" of the landscape would otherwise be the flat, featureless plains of cratons, or rather ordinary-looking plateaux, hills and mountain-ridges lifted by tectonic processes.

Erosion creates valleys etc - -but it also is responsible over geological time for creating sediment deposits that become sedimentary rocks. When in turn these are uplifted into hills and plateaux, their differing characteristics give differing erosion results, enriching the landscape's variety.

It also creates the matrix of rock particles and soluble minerals needed as the basis of soil, necessary to support vegetation hence terrestrial life.

In fact had their been no erosion at all since the planet formed, the landscape would be of nothing but igneous rock, and mostly bare rock at that. The only vegetation on land, if any, to have evolved would have been very highly-specialised algae and bacteria. But whence would they have drawn their nutrients? If their only source of food was the rock then that would have created a very slow form of erosion.