Final answer:
Keystone species are crucial to their ecosystems, impacting them significantly beyond their numbers. They help maintain balance by regulating populations of other species, and their removal can lead to significant ecological changes. Understanding a species' ecological niche is crucial for grasping its role in the ecosystem.
Step-by-step explanation:
Some species, known as keystone species, are particularly crucial to the functioning and structure of their ecosystem. Keystone species have a disproportionately large impact on their environment relative to their abundance. These species help maintain the structure of an ecological community by regulating the numbers and types of other species present; their removal can lead to a dramatic change in the ecosystem.
For example, predators can often be keystone species. Their hunting activities help to maintain the balance of prey populations and therefore preserve the diversity of the community. If predators are removed, certain prey populations may increase unchecked, which can lead to overgrazing or depletion of vegetation and subsequent impacts on other species. Thus, the concept of an ecological niche is vital to understanding the role each organism plays within the ecosystem, including their interactions with both biotic and abiotic factors.