bio topic 4

Question 1

Which statement applies to transfers in an ecosystem?
A. Green plants can transfer heat energy from the sun into chemical energy.
B. The greatest loss of energy occurs towards the end of a food chain.
C. Production of carbon dioxide by respiration results in loss of biomass in a food chain.
D. Both energy and nutrients are finite and must be recycled.

Answer 1

C

Question 2

Which processes occur in an ecosystem?

Answer 2

• Inorganic compounds are recycled
• Chemical energy is stored in carbon compounds

Question 3

How can a chi-squared test be used in ecological research?
A. To test the effect of an abiotic factor on one plant species
B. To test whether two species tend to live together
C. To test whether one population of plants is taller than another
D. To test whether one species is more tolerant to heavy metals than another

Answer 3

B

Question 3

Which organism would be classified as a saprotroph?
A. A single-celled eukaryote that obtains its carbon compounds by photosynthesis and ingestion of other single-celled organisms
B. 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
C. A fungus that feeds by secretion of digestive enzymes onto its food and absorption of digested material
D. A dung beetle that feeds on the fecal material left behind by other animals

Answer 3

C

Question 4

Two populations of the same fish species were fed different diets to investigate the effect of differing nutrition on their growth. What is an appropriate method to determine the significance of a resulting difference?

Answer 4

Perform a T-test

Question 5

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?

Answer 5

A community

Question 6

What is a community composed of?

Answer 6

Populations

Question 7

In a pond, two species of fish feed on insects and worms. The insects feed on the green plants that live in the water. What constitutes a population in this ecosystem?
A. All the living organisms
B. All the animals
C. All the fish
D. All the fish of one species

Answer 7

D

Question 8

How do methanogenic archaeans living in peat bogs obtain energy to survive?

Answer 8

They synthesize methane from carbo dioxide released by decomposing peat

Question 9

The ability to digest lactose in adulthood appeared due to a mutation in the lactase gene.
The frequency of the lactase persistence allele was recorded as 0.8 in present-day European
populations and as 0.05 in fossils from populations of their prehistoric ancestors.
What could have caused the change in the allele frequency?

Answer 9

There was a strong positive selection for the lactase persistence allele

Question 10

Which process transfers the largest mass of carbon per year in a woodland ecosystem?

Answer 10

CO2 in atmosphere and dissolved in water to green plants

Question 11

Plankton are major producers in marine ecosystems. Only a small proportion of the energy harvested by plankton is passed to the primary consumers. Which process in phytoplankton results in the largest loss of energy that could otherwise be utilized by consumers?

Answer 11

Respiration

Question 12

Bacteria play an important role in recycling nutrients in ecosystems. They live on organic wastes and dead organisms and digest their molecules. They then absorb some of these molecules for their own metabolism, and the rest is used by other organisms. What is the mode of nutrition of these bacteria?

Answer 12

Saprotrophs

Question 13

How is energy lost between trophic levels?

Answer 13

Respiration, death of an organism and egestion

Question 14

The global carbon cycle involves sinks where carbon is stored, and fluxes where carbon is transferred. What are the largest sink and flux?

Answer 14

Oceans, photosynthesis

Question 15

Which organisms produce methane in anaerobic environments such as waterlogged soils?

Answer 15

Archaea

Question 16

What material is formed when organic matter is not fully decomposed in acidic waterlogged soils?

Answer 16

Peat

Question 17

What favours the production of peat?

Answer 17

• Presence of organic matter
• Anaerobic conditions
• Acidic conditions

Question 18

Methanogens produce methane gas. What is this gas converted to in the atmosphere?

Answer 18

Carbon dioxide and water

Question 19

How is peat formed?

Answer 19

From partially decomposed organic matter in acidic and anaerobic conditions in waterlogged soils

Question 20

Which hypothesis is supported by evidence from ecological research?

Answer 20

Producers use nutrients that decomposers help to recycle

Question 21

What is a potential consequence of the rise in global temperatures?

Answer 21

Changes to circulating ocean currents

Question 22

The oceans absorb much of the carbon dioxide in the atmosphere. The combustion of fossil fuels has increased carbon dioxide ocean concentrations. What adverse effect does this have on marine life?

Answer 22

Corals deposit less calcium carbonate to form skeletons.

Question 23

What contributes to rising atmospheric concentrations of carbon dioxide and increases in average global temperature?

Answer 23

An increase in the combustion of fossilized organic matter

Question 24

What is the best definition of the greenhouse effect in the Earth’s atmosphere?

Answer 24

A naturally occurring effect by which longer wavelength radiation is trapped

Question 25

Global warming caused by the enhanced greenhouse effect is likely to have major consequences for arctic ecosystems. Which of the following are likely to occur in the arctic if the Earth’s surface temperature rises?

Answer 25

- Increased range of predators from temperate regions - Increase in numbers of pest species and pathogens

Question 26

What is an example of the precautionary principle?

Answer 26

Reducing carbon dioxide emissions as they may cause global warming

Question 27

Which of the following is a consequence of global temperature rise on arctic ecosystems?

Answer 27

Increased rates of decomposition of detritus trapped in permafrost