Unit 3 reveiw

What can you conclude from the fact that more than a billion species have gone extinct during the 4.5 billion year history of the Earth?

• Extinction is not natural and can be stopped.

• Extinction can only occur if humans are still a impact.

• Extinction is a natural process that can not be stopped.

If sheep survived mainly on grass and there was a fire that eliminated their food source, what would happen to the sheep?

• The sheep population would increase.

• The sheep population would stay the same.

• The sheep population would decrease.

• The sheep population would go extinct.

In Yellowstone National Park, the wolves were removed to protect livestock. Their removal changed the ecosystem drastically. They might be called

• A keystone species

• A primary consumer

• a limiting factor

• a primary consumer

What happens to an ecosystem when a population becomes overpopulated?

• Orgainisms that rely on the same resources will increase.

• Orgainisms that rely on the same resources will decrease.

• Orgainisms that rely on the same resources will stay the same.

If producers were to increase in an ecosystem, how will that affect the other trophic levels?

• The orgainsms would increase in trophic levels.

• The orgainsms would decrease in trophic levels.

• Orgainsms would stay the same in trophic levels.

What would happen if two species lived in the same niche?

• The two species would eat each other and both die off.

• The two species would go in competition and one of the species would die out.

• The two species would reach equailbruim and be just fine.

• Both of the species would have to move to different ecosystems.

Which definition best describes the relationship between a parasite and its host?

• A symbiotic relationship where one species benefits and the other is harmed.

• A symbiotic relationship where both species benefit.

• A symbiotic relationship where one species benefits and the other does not benefit nor is it harmed.

• A symbiotic relationship where one species is eaten by the other.

How would an organism that has very few predators affect an ecosystem if it were to die out?

• The producers would die out.

• The whole ecosystem would die out.

• The ecosystem would reach equilibrium.

• The herbivores would overpopulate.

When a new species is introduced into an ecosystem, the population of their prey species will decrease.

• TRUE

• FALSE

If humans began removing one species in an ecosystem, how will that affect the other species?

• The species in the trophic levels below the species will INCREASE while the species in trophic levels above the species will DECREASE.

• The species in the trophic levels below the species will DECREASE while the species in trophic levels above the species will INCREASE.

• The species in the trophic levels below the species will STAY THE SAME while the species in trophic levels above the species will DECREASE.

• The species in the trophic levels below the species will INCREASE while the species in trophic levels above the species will STAY THE SAME.