Organisms and Population
Test 5

Correct answer Carries: 4.

Wrong Answer Carries: -1.

In which type of age pyramid does the pre-reproductive population size dominate?

Stable
Declining
Expanding
None of the above
3

An expanding age pyramid has a broad base, indicating a high proportion of pre-reproductive individuals.

Which of the following interactions is NOT correctly matched?

Commensalism - One benefits, other is unaffected
Parasitism - Both species benefit
Mutualism - Both species benefit
Competition - Both species are harmed
2

Parasitism benefits the parasite while harming the host, unlike mutualism where both species benefit.

Which of the following is an example of cryptic coloration?

A vulture feeding on dead animals
A chameleon changing color to blend with its surroundings
A cuckoo laying eggs in a crow’s nest
A mosquito feeding on human blood
2

Cryptic coloration helps organisms blend with their surroundings to avoid predators, as seen in chameleons.

Which of the following statements about food chains is correct?

Energy flow in a food chain is unidirectional.
All organisms in a food chain occupy the same trophic level.
Primary consumers feed on secondary consumers.
Producers obtain energy from consumers.
1

Energy in a food chain flows in one direction, from producers to consumers and then to decomposers.

Which of the following is an incorrect statement about keystone species?

Keystone species have a significant impact on ecosystem stability.
They are always the most abundant species in an ecosystem.
Removing a keystone species can cause ecosystem collapse.
Predators and primary producers can both be keystone species.
2

Keystone species are not necessarily the most abundant but play a critical role in maintaining ecosystem structure.

Which of the following statements about biodiversity is correct?

Higher biodiversity leads to greater ecosystem stability.
Biodiversity is unaffected by habitat destruction.
Ecosystems with low biodiversity are more resilient to disturbances.
Biodiversity only refers to the number of different species in an ecosystem.
1

Higher biodiversity increases ecosystem stability and resilience to environmental changes.

Which of the following statements about invasive species is incorrect?

Invasive species can outcompete native species.
They always improve ecosystem biodiversity.
Invasive species may lack natural predators in their new habitat.
They can alter ecosystem structure and function.
2

Invasive species often reduce biodiversity by outcompeting native species and disrupting ecosystem balance.

What is Gause’s Competitive Exclusion Principle?

Two species can coexist indefinitely in the same niche.
Two closely related species cannot coexist indefinitely in the same niche.
Competition always results in extinction.
Herbivory is a type of competition.
2

Gause’s Competitive Exclusion Principle states that when two species compete for the same resources, the inferior competitor will be eliminated.

Which of the following interactions is observed between sea anemone and clownfish?

Predation
Parasitism
Commensalism
Mutualism
3

The clownfish benefits from the protection of the sea anemone, while the sea anemone remains unaffected.

Which of the following is an r-selected species characteristic?

Long lifespan
Few offspring with high parental care
Rapid reproduction and high number of offspring
Slow development
3

r-selected species reproduce rapidly, producing many offspring with little or no parental care.

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