Answer :
Final answer:
A keystone species, like the intertidal sea star, has a disproportionate impact on its environment relative to its abundance, affecting biodiversity and community structure. A foundation species, such as kelp, is abundant and forms the basis of an ecosystem, significantly influencing its overall structure.
Explanation:
The distinction between a keystone species and a foundation species lies in their roles within an ecosystem. A keystone species has a disproportionately large effect on its environment relative to its abundance.
For example, the intertidal sea star Pisaster ochraceus is a keystone species in the northwestern United States with the ability to greatly influence species composition and biodiversity.
In contrast, a foundation species often dominates an ecosystem in abundance and forms the base of the community, for instance, the kelp forests formed by kelp in the coast of California. Both are crucial for ecosystem health, but they play very different roles in maintaining the ecological community's structure and dynamics.
