In today's biology lecture, we're discussing the concept of keystone species. A keystone species is one whose impact on its ecosystem is disproportionately large relative to its abundance. The term was first coined by ecologist Robert Paine in 1969 after his famous experiments with starfish in tidal pools. When Paine removed the starfish, a predator, from the pools, the population of mussels, which were the starfish's primary prey, exploded. This caused a dramatic decrease in biodiversity, as mussels outcompeted other species for space and resources. Interestingly, the starfish were not the most numerous species in the pool, yet their presence was critical for maintaining the balance. This example illustrates that keystone species often have a controlling effect on the structure of their community, and their removal can lead to cascading effects. In conservation, identifying keystone species is vital because protecting them can help preserve the overall health of the ecosystem, even if we cannot protect every species.
❓ Question What is the main point the professor makes about keystone species?
A. A. They are always the most abundant species in an ecosystem.
B. B. Their impact is much larger than their numbers would suggest.
C. C. They are only found in tidal pools.
D. D. Their removal usually has no effect on biodiversity.
✅ Correct Answer
B. Their impact is much larger than their numbers would suggest.
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