Biodiversity and Keystone Species

What is a keystone species?

• A species that helps to hold an ecosystem together

• A species that lives in or around rocks

• Keys and stones have nothing to do with ecology

• A keystone isn't a living thing, it's just a stone

Based on the graph shown, what is the effect of removing a keystone species from an ecosystem?

• biodiversity goes up
• biodiversity goes down
• biodiversity stays about the same
• not enough information to tell

Based on the graph shown, how can you tell sea otters are a keystone species?

• as the sea otter population decreases, biodiversity increases
• as sea otter population increases, biodiversity increases
• changes in the sea otter population have little effect on biodiversity 
• the sea otter population dereases due to the presence of urchins

The particular role (job) of an organism in its environment including types of food it eats, how it obtains its food and how it interacts with other organisms is called a what?

• niche
• habitat
• home
• ecosystem

Study the graph. Based on the data shown, rainbow smelt are a/an _____________.

• invasive species
• keystone species
• symbiotic species
• not enough information to tell

A sea otter and a sea star are examples of...

• invasive species
• keystone species
• native species 
• symbiotic species

A species that maintain biodiversity by keeping prey populations controlled are called...

• Introduced Species
• Apex Predators
• Invasive Species
• Keystone Species

The term biodiversity means:

• a wide variety of plants and animals in an ecosystem
• only a few types of plants and animals in an ecosystem
• an ecosystem composed mostly of plants
• an ecosystem composed mostly of animals