Ecosystem Dynamics and Keystone Species

The video explores the concept of keystone species, which play a crucial role in maintaining ecosystem balance. Using analogies and examples, it explains how the removal of these species can lead to significant changes in the ecosystem. Examples include sea otters in kelp forests, wolves in Yellowstone, Banksia plants in Australia, and sea stars in marine environments. Each example illustrates the disproportionate impact these species have on their ecosystems, despite their relatively low numbers.

What is the role of a keystone species in an ecosystem?

• They have a disproportionate effect on their ecosystem.

• They are the primary producers in the ecosystem.

• They are the most abundant species.

• They are the largest species in the ecosystem.

What happens if a keystone species is removed from an ecosystem?

• The ecosystem remains unchanged.

• The ecosystem becomes more diverse.

• There are significant impacts on the ecosystem.

• The ecosystem becomes more stable.

How do sea otters affect the sea kelp ecosystem?

• They control the sea urchin population.

• They eat sea kelp.

• They increase the number of sea urchins.

• They have no effect on the ecosystem.

What was the effect of reintroducing wolves to Yellowstone National Park?

• Increased number of herbivores.

• Decreased plant diversity.

• Increased plant regrowth and diversity.

• No significant change in the ecosystem.

Why did the beaver population decrease in Yellowstone before the reintroduction of wolves?

• Lack of food due to overgrazing by herbivores.

• Increased predation by wolves.

• Competition with other beavers.

• Lack of water resources.

What is the significance of the Banksia plant in Australian ecosystems?

• It is the primary food source for all animals.

• It provides nectar for honeyeaters, aiding in pollination.

• It has no significant role in the ecosystem.

• It is the largest plant species in Australia.

What would happen if the Banksia plant were removed from its ecosystem?

• Increased pollination of other plants.

• Decrease in honeyeater population and pollination.

• No effect on the ecosystem.

• Increase in plant diversity.

What is the primary diet of the sea star in marine ecosystems?

• Algae and seaweed.

• Coral and sponges.

• Small fish and plankton.

• Mussels and other shellfish.

What is the consequence of removing sea stars from their ecosystem?

• No significant change in the ecosystem.

• Decrease in mussel population.

• Overgrowth of mussels, reducing space for other species.

• Increase in fish population.

Why are sea stars not referred to as starfish?

• They are not actually fish.

• They are a type of plant.

• They live in freshwater.

• They are a type of coral.