The Role of Keystone Species in Ecosystems

Today, we’ll discuss the concept of keystone species and their crucial role in ecosystems. A keystone species is one that has a disproportionately large impact on its environment relative to its abundance.

For example, sea otters are considered a keystone species in the North Pacific Ocean. They prey on sea urchins, which, if left unchecked, can decimate kelp forests by overgrazing. Kelp forests provide habitat and food for a diverse range of marine organisms. Without sea otters, the sea urchin population would explode, leading to the destruction of these vital ecosystems. Thus, the presence or absence of a keystone species like the sea otter can dramatically alter the ecosystem structure and health.

Key Points:

• Keystone species have a significant impact on their ecosystems.
• Example: Sea otters control sea urchin populations, protecting kelp forests.
• Without keystone species, ecosystems can be severely disrupted.

Sample Answer: The lecture explains that keystone species play a critical role in maintaining the balance of ecosystems. The professor uses sea otters as an example, highlighting how they control the population of sea urchins in the North Pacific. Sea urchins can destroy kelp forests if their numbers aren't managed. Since these forests are essential for many marine species, the otters' presence ensures the ecosystem remains healthy. In conclusion, keystone species, like sea otters, are vital because their absence can lead to significant ecological disruptions.