There are many environments on earth. Some environments are dry with very hard soils some are humid with very thick, soft soils. Some environments are hilly others are flat. Some are deep under water, others are on rocky ground. Some have streams of water some have streams of slowly moving ice.
All environments give animals and plants special problems.
Dry environments require animals and plants to deal with the lack of water by saving the water they have or by finding ways to get water. In all kinds of environments plants and animals compete for the water, food, and space that is available. If an environment remains the same for thousands of years, then animals and plants can stay the same and survive. The giant redwood and sequoia trees in California have grown in an environment that has stayed the same for at least 3,000 years. Sometimes an environment changes over a few hundreds or even thousands of years.