Answer :
Final answer:
A keystone species is crucial to ecosystem function and maintains biodiversity, while an invasive species is non-native and often disrupts the community it invades by out-competing native species.
Explanation:
The difference between a keystone species and an invasive species relates to their role and origin in an ecosystem. A keystone species is a central component of an ecosystem that maintains biodiversity and has a disproportionately large impact on its environment relative to its abundance. For instance, the intertidal sea star, Pisaster ochraceus, is a keystone species because its predation on mussels allows for greater species diversity. On the other hand, an invasive species is a non-native organism that disrupts the ecosystems it invades by out-competing native species and often causing ecological harm. An example is the pampas grass, which quickly colonizes and reduces biodiversity in environments outside its native range.
