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:
Biomass available after transfer/Biomass available before transfer

Question 18

Extremophiles:

Answer 18

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

Question 19

Food chain:

Answer 19

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

Mean:

Answer 24

The average of a set of numbers calculated by dividing the sum of the values by the number of values.

Question 25

Median:

Answer 25

The middle number in a list of values ordered from lowest to highest.

Question 26

Microorganisms:

Answer 26

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 27

Mode:

Answer 27

The number that occurs most commonly in a set of data values.

Question 28

Mycoprotein:

Answer 28

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

Question 29

Peatlands:

Answer 29

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 30

Pollution:

Answer 30

Contamination or destruction of the natural environment due to human intervention.

Question 31

Population:

Answer 31

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

Question 32

Predators:

Answer 32

Consumers that prey on and eat other animals.

Question 33

Prey:

Answer 33

Animals that are eaten by predators.

Question 34

Primary consumers:

Answer 34

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

Question 35

Producers:

Answer 35

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

Question 36

Pyramid of biomass:

Answer 36

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 37

Quadrat:

Answer 37

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

Question 38

Secondary consumers:

Answer 38

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

Question 39

Sustainable:

Answer 39

The ability to maintain something for future generations.

Question 40

Sustainable fisheries:

Answer 40

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

Question 41

Tertiary consumers:

Answer 41

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

Question 42

Transect:

Answer 42

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

Question 43

Trophic level:

Answer 43

The position of an organism in a food chain.

Question 44

Water cycle:

Answer 44

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