Keystone Species and Ecosystem Dynamics

Adele Caldwell, a biology student, introduces key ecological concepts focusing on kelp forests. The video explains trophic cascades, food chains, and the role of keystone species like sea otters in maintaining ecosystem balance. It discusses the green world hypothesis and the impact of predators on herbivore populations, using the Aleutian Islands as a case study. The video concludes with reflective questions and further reading suggestions.

What is the primary focus of the ecological concepts discussed in the video?

• Grasslands

• Rainforests

• Kelp forests

• Desert ecosystems

What does the term 'trophic' relate to?

• Food or nutrition

• Animal behavior

• Water cycles

• Climate change

In a kelp forest food chain, what is the primary source of energy?

• Sea urchins

• Kelp

• Sea otters

• The sun

What role do sea otters play in the kelp forest ecosystem?

• They are decomposers

• They are primary producers

• They are herbivores

• They are keystone species

What is the green world hypothesis?

• Herbivores control plant growth

• Predators keep herbivore populations in check

• Ecosystems are self-sustaining

• Plants grow without sunlight

What unusual predator was found to be eating sea otters in the Aleutian Islands?

• Dolphins

• Sharks

• Orcas

• Seals

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

• It becomes more stable

• It collapses

• It remains unchanged

• It becomes more diverse

Who first used the term 'keystone species'?

• Jim Estes

• Robert Payne

• Nelson Harrison

• Frederick Smith

Why are keystone species often top predators?

• They are the most numerous

• They have a large impact despite their small numbers

• They are the most intelligent

• They are the largest animals

What analogy is used to describe the role of a keystone species in an ecosystem?

• A ladder

• A pyramid

• A bridge

• An arch