Topic 7:Ecology

Question 1

Abiotic factors

Answer 1

The non-living aspects of an ecosystem e.g. temperature, light intensity, moisture, wind direction, wind intensity, soil pH, soil mineral content, carbon dioxide levels
and oxygen levels.

Question 2

Adaptation

Answer 2

A feature of an organism that increases its chance of survival in its environment.
Such features may be behavioural, structural or functional.

Question 3

Anaerobic decay

Answer 3

Decomposition in the absence of oxygen (commonly occurring in waterlogged soils) that produces carbon dioxide and methane gas.

Question 4

Apex predator

Answer 4

A carnivore at the top of the food chain with no predators.

Question 5

Biodiversity

Answer 5

The variety of living organisms in an ecosystem

Question 6

Biogas

Answer 6

A type of biofuel (methane gas) produced by anaerobic decay in biogas generators.

Question 7

Biotic factors

Answer 7

The living components of an ecosystem e.g. food availability, pathogens, predators and other species.

Question 8

Carbon cycle

Answer 8

The cycle through which carbon (in the form of carbon dioxide) moves between living organisms and the environment, involving respiration, photosynthesis and
combustion.

Question 9

Community

Answer 9

All of the populations of different species living together in a habitat

Question 10

Competition

Answer 10

When different organisms compete for the same resources (e.g. light, water, mates, territory) in an ecosystem. This limits population sizes and stimulates evolutionary
change.

Question 11

Compost

Answer 11

Dead and decaying organic matter, commonly used as a fertiliser.

Question 12

Decomposers

Answer 12

Organisms that release enzymes which catalyse the breakdown of dead
plant and animal material into simpler organic matter.

Question 13

Decomposition

Answer 13

The breakdown of dead materials into simpler organic matter. The rate of decomposition is affected by temperature, water and oxygen availability

Question 14

Deforestation

Answer 14

The removal of trees from land which is subsequently used to grow crops or provide space for cattle.

Question 15

Distribution

Answer 15

The spread of living organisms in an ecosystem. It is affected by environmental changes which may be seasonal, geographic or man-made

Question 16

Ecosystem

Answer 16

The community of organisms (biotic) and non-living (abiotic) components of an area and their interactions

Question 17

Efficiency of biomass transfer

Answer 17

The efficiency of biomass transfer between trophic levels is
calculated using: efficency=biomass available after transfer/biomass available before transfer x100

Question 18

Extremophiles

Answer 18

Organisms that can live in extreme environments e.g. high temperatures, high salinity.

Question 19

Food chain

Answer 19

Food chain: Describes the feeding relationships between organisms and the resultant
stages of biomass transfer. It takes the form:
producer ⟶ primary consumer ⟶ secondary consumer ⟶ tertiary consumer

Question 20

Food security

Answer 20

Ensuring that populations have access to adequate amounts of safe and nutritious food.

Question 21

Global warming

Answer 21

The gradual rise in the average temperature of the Earth due to increasing atmospheric levels of carbon dioxide and methane gas

Question 22

GM crops

Answer 22

Crops that have had their genomes modified by the insertion of a desired gene
from another organism.

Question 23

Interdependence

Answer 23

The dependence of different organisms on each other for survival e.g.
plants depend on pollinators, herbivores depend on plants.

Question 24

Microorganisms

Answer 24

Very small organisms involved in the recycling of materials in an ecosystem. They return mineral ions to the soil and convert carbon to carbon dioxide which is released into the atmosphere.

Question 25

Mycoprotein

Answer 25

A food high in protein (suitable for vegetarians) that is produced by the
microorganism, Fusarium, in fermentation vats

Question 26

Peatlands

Answer 26

Areas of peat soil in wetland habitats formed by the accumulation of partially decayed organic matter. Peat is commonly used as a garden compost.

Question 27

Pollution

Answer 27

Contamination or destruction of the natural environment due to human
intervention

Question 28

Population

Answer 28

All organisms of the same species living with one another in a habitat.

Question 29

Predators

Answer 29

Consumers that prey on and eat other animals

Question 30

Prey

Answer 30

Animals that are eaten by predators.

Question 31

Primary consumers

Answer 31

Herbivores that consume producers at trophic level 2 of a food chain.

Question 32

Producers

Answer 32

Photosynthetic organisms (e.g. green plant or alga) at the start of the food chain 
that provide biomass for all living things.

Question 33

Pyramid of biomass

Answer 33

A table of the dry mass of living material at each trophic level of a
food chain. This forms the shape of a pyramid.

Question 34

Quadrat

Answer 34

A square grid of known area used in sampling to determine the abundance and distribution of organisms in an ecosystem.

Question 35

Secondary consumers

Answer 35

Carnivores that consume herbivores at trophic level 3 of a food chain.

Question 36

Sustainable

Answer 36

The ability to maintain something for future generations.

Question 37

Sustainable fisheries

Answer 37

Methods of harvesting fish at a sustainable rate and increasing fish stocks, for example, by controlling net size or introducing fishing quotas.

Question 38

Tertiary consumers

Answer 38

Carnivores that consume other carnivores at trophic levels 4 and above of a food chain.

Question 39

Transect

Answer 39

A line along an area used in sampling to determine the abundance and distribution of organisms in an ecosystem.

Question 40

Trophic level

Answer 40

The position of an organism in a food chain.

Question 41

Water cycle

Answer 41

The cycle through which water moves between living organisms and the environment, involving evaporation, transpiration, condensation and precipitation.