Ecological relationships and energy flow

Question 1

What is a population?

Answer 1

The number of organisms of the same species living in the same area

Question 2

What is a habitat?

Answer 2

The area where a population lives

Question 3

What is a community?

Answer 3

A group of populations living in habitats close together

Question 4

What is biodiversity?

Answer 4

The measure of the number of different species living in the area

Question 5

What is the environment?

Answer 5

The conditions which surround and effect an organism in their habitat

Question 6

What is an abiotic factor?

Answer 6

A non-living factor such as temperature, humidity, light intensity

Question 7

What is a biotic factor?

Answer 7

A living factor such as the effect of a predator on its prey

Question 8

What is an ecosystem?

Answer 8

An area in which a community of organisms interact with each other and their physical surroundings

Question 9

What is sampling?

Answer 9

A process used to give a good estimate of the number, or percentage cover, of an organism in a particular area

Question 10

What is a quadrat?

Answer 10

A square frame used as a subsection for sampling

Question 11

What is number sampling? When is it used?

Answer 11

Counts the number of organisms in a sample. Used when the number of individuals is easy to determine

Question 12

What is percentage cover sampling? When is it used?

Answer 12

Measures the percentage area an organism or individual covers in a sample. Used when it is difficult to determine where one individual stops and another one starts

Question 13

What is random sampling? (3)

Answer 13

• Drawing samples from an area at random intervals.
• Carried out when the area is uniform.
• Enough samples should be used to give a representative sample of an area and quadrats should be positioned using random numbers to avoid bias.

Question 14

What is belt transect sampling?

Answer 14

Sampling using quadrats placed at regular intervals. Used when zonation is present

Question 15

What is competition in animals usually for? (4)

Answer 15

Food, water, territory, and mates

Question 16

How can competition occur?

Answer 16

When a number of animals or plants have to compete for the same desired resources

Question 17

What is competition in plants usually for? (5)

Answer 17

Light, carbon dioxide, water, minerals and space

Question 18

What is a food chain?

Answer 18

A sequence of organisms which feed off each other, passing nutrients and energy

Question 19

What is a food web?

Answer 19

A number of interlinked food chains

Question 20

What is a producer in a food web?

Answer 20

An organism that produces, a plant, which is at the start of a food chain

Question 21

What is a consumer?

Answer 21

An animal that gains its food from consuming other organisms

Question 22

What do the arrows in a food chain represent?

Answer 22

Energy flow

Question 23

What are trophic levels? (2)

Answer 23

• The level at which an organism feeds in a food chain or web
• The different stages of the feeding process in a food chain or web

Question 24

What is the source of energy in a food chain?

Answer 24

The sun

Question 25

What is a pyramid of numbers?

Answer 25

A diagram showing the numbers of organisms at each stage (trophic level) of a food chain

Question 26

What is a pyramid of biomass?

Answer 26

A diagram showing the mass of living tissue, biomass, at each stage of a food chain

Question 27

Why are pyramids of numbers and biomass referred to as a pyramid?

Answer 27

The number of organisms usually decreases with increasing trophic level

Question 28

Why is a pyramid of numbers not accurate?

Answer 28

Many small organisms could feed off of one big one such as 5mm long insects feeding off a single 100m tall tree

Question 29

How is energy lost at each trophic level? (3)

Answer 29

• Not all the available food is eaten (skeleton, fur)
• Not all the food is digested, some is egested as faeces
• Energy is lost as heat in respiration

Question 30

What is competition?

Answer 30

The ‘battle’ between living organisms for the same resource or resources

Question 31

What is a nutrient cycle?

Answer 31

The cycling of substances in the environment

Question 32

What is a decomposer?

Answer 32

An organism which breaks down the tissues of dead organisms and excretory products

Question 33

What is decomposition?

Answer 33

The breaking down of dead organisms into small pieces

Question 34

What do fungi and bacteria do in the decomposition process?

Answer 34

Breaking down the organic compounds into their simplest components, which plants can absorb and use again

Question 35

What is meant by the term saphrophyte?

Answer 35

A bacterium or fungus which decomposes material by releasing enzymes onto the surface and absorbing the breakdown products

Question 36

What is humus?

Answer 36

The organic content of the soil formed from decomposing plant and animal material

Question 37

What are the optimum conditions for decomposition? (3)

Answer 37

• A warm temperature
• Adequate moisture
• A large surface area in the decomposing organism

Question 38

What is the carbon cycle?

Answer 38

The cycling of carbon-containing substances in the environment

Question 39

What are the main processes in the carbon cycle? (6)

Answer 39

• Photosynthesis
• Feeding
• Respiration
• Decomposition
• Fossilisation
• Combustion

Question 40

What processes have added to the increase of carbon dioxide in the atmosphere, and what is a result of this?

Answer 40

Combustion and deforestation have allowed the carbon dioxide concentration to become unbalanced as more carbon dioxide is being given off than can be taken in

Question 41

How does carbon dioxide assist global warming?

Answer 41

Carbon dioxide and other gases in the atmosphere create a ‘greenhouse blanket’ which traps the heat from the sun within the atmosphere

Question 42

What are the effects of global warming? (5)

Answer 42

• Climate change
• Polar ice caps melting
• Increased sea levels and flooding
• More land becoming desert
• Loss of habitats

Question 43

What can be done to lessen the effects of global warming? (3)

Answer 43

• Plant more trees
• Reduce deforestation
• Burn fewer fossil fuels (use more efficient fuels)

Question 44

What are the three parts of the nitrogen cycle?

Answer 44

• Nitrification
• Nitrogen fixing
• Denitrification

Question 45

What is nitrification?

Answer 45

The process by which ammonia is converted to nitrates

Question 46

What are nitrifying bacteria?

Answer 46

The bacteria which converts ammonia to nitrates

Question 47

What are nitrogen fixing bacteria?

Answer 47

A special group of bacteria that can convert nitrogen gas into nitrates

Question 48

Where can nitrogen fixing bacteria be found?

Answer 48

In nodules in the roots of legumes (such as peas, beans and clover)

Question 49

What is nitrogen fixation?

Answer 49

A process which allows bacteria to change nitrogen gas into nitrates

Question 50

What are denitrifying bacteria?

Answer 50

Bacteria that convert nitrates into atmospheric nitrogen

Question 51

How can the processes of nitrification and nitrogen fixation be accelerated? (2)

Answer 51

• Higher temperatures
• Aerated soil

Question 52

Where are denitrification bacteria most commonly found?

Answer 52

In waterlogged soils

Question 53

What are the 3 beneficial bacteria for the nitrogen cycle?
Also
What is the negative bacteria for the nitrogen cycle?

Answer 53

Beneficial:
- nitrifying
- nitrogen-fixing
- decay

Negative:
- denitrifying

Question 54

Why is soil more fertile when legumes (peas, beans, clover etc) are grown? (3)

Answer 54

• legumes contain nodules in their roots which contain nitrogen-fixing bacteria
• which converts Nitrogen gas to Nitrates
• which fertilises the soil

Question 55

What is meant by the term decay? (2)

Answer 55

• saprophytic digestion via decomposers (decay bacteria and fungi)
• which convert dead organic matter to ammonia

(Preceded by breakdown by detritivores)