Topic 4 Review

What is exchanged between a sealed mesocosm and the surrounding external environment?

• Energy

• Water

• Air

• Nothing can pass

In a woodland ecosystem, each tree provides food for numerous aphids which feed on the sap of the tree. The aphids are eaten by carnivorous beetles, as shown in the food chain.

Oak Tree → Aphids → Beetles

Which pyramid of energy represents this relationship?

• A

• B

• C

• D

How do greenhouse gases contribute to global warming?

• They destroy the ozone layer, allowing radiation to reach the Earth’s surface.

• They prevent radiation from the Earth escaping into space

• They trap short wavelength radiation in the atmosphere.

• They are a product of combustion, which generates heat.

Over time, the hull of a sunken ship may become colonized by a wide range of marine organisms. What term is used to describe all of the organisms living in and on a sunken ship?

• A community

• An ecological niche

• A population

• An ecosystem

The diagram shows the energy flow between five “sinks” in a terrestrial ecosystem.

In a typical terrestrial ecosystem, which trophic level would have the highest biomass?

• Autotrophs

• Primary consumers

• Secondary consumers

• Detritus feeders

Which organism would be classified as a saprotroph?

• A single-celled eukaryote that obtains its carbon compounds by photosynthesis and ingestion of other single-celled organisms

• A jellyfish that uses the stinging cells in its tentacles to paralyse its prey, which is passed to an internal gastric cavity through a single opening

• A fungus that feeds by secretion of digestive enzymes onto its food and absorption of digested material

• A dung beetle that feeds on the fecal material left behind by other animals

The diagram shows the flow of energy through an ecosystem in kJm–2y–1. What percentage of the energy passed from primary producers to primary consumers is lost to cellular respiration by tertiary consumers?

• 0.001%

• 0.08%

• 0.2%

• 0.4%

Which gases have made the most significant contributions to global warming?

• Water and carbon dioxide

• Carbon dioxide and methane

• Methane and nitrous oxide

• Carbon dioxide and ozone

Which level(s) of ecological complexity involve(s) biotic factors but not abiotic factors?

I. Community

II. Ecosystem

III. Population

• I only

• II only

• I and II only

• I and III only

How can a chi-squared test be used in ecological research?

• To test the effect of an abiotic factor on one plant species

• To test whether two species tend to live together

• To test whether one population of plants is taller than another

• To test whether one species is more tolerant to heavy metals than another