Natural selection is the process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment. For example, treefrogs are sometimes eaten by snakes and birds.
The amount of stuff that an ecosystem
If a species is said to be extinct, then that species is reduced to zero. There are none living in existence. The affects to other organisms of its extinction would depend on their value to the ecosystem. Regardless, extinction completely stops evolution of the species extinct.
