Ecology

Question 1

What is a producer?

Answer 1

Organisms which make their own food

Question 2

What is a consumer?

Answer 2

Organisms which eat other living things

Question 3

What is a decomposer?

Answer 3

Organisms which secrete digestive enzymes to decay dead organic matter to obtain their food, they helps to recycle nutrients

Question 4

What is a physical environment?

Answer 4

All the non-living factors which affect growth and survival of living things.

Question 5

What is a habitat?

Answer 5

The place where specific organisms live

Question 6

What is a population?

Answer 6

The total number of individuals of one species in a particular habitat at a particular time.

Question 7

How would an ecologist measure the size of a population in a habitat?

Answer 7

1. Calculate the area of the habitat
2. Measure the number of individuals in one quadrat and repeat many times to check our result is reliable
3. Calculate the average number of individuals in a quadrat
4. Calculate how many quadrats fit into the total area
5. Multiply the average by the number of quadrats that fit into the area

Question 8

What method of sampling would we use to make sure our data is valid for finding the population?

Answer 8

Random sampling to avoid bias

Question 9

What is a community?

Answer 9

It is formed of the populations of all the species present in an ecosystem at a particular time.

Question 10

What are the stages in a food chain called?

Answer 10

Tropic levels

Question 11

What are some examples of biotic factors?

Answer 11

Food availability
Predators
Competition from other organisms
Infection from pathogens

Question 12

What are some examples of abiotic factors?

Answer 12

Sunlight
Temperature
pH
Water
Minerals
Soil type
Salinity

Question 13

What do pyramids of number show?

Answer 13

The number of each organism in the ecosystem.

Question 14

What do pyramids of biomass show?

Answer 14

The total mass of the organisms in each trophic level.

Question 15

What do pyramids of energy show?

Answer 15

The total energy available in each tropic level per square metre per year.

Question 16

The least efficient transfer is from light energy to the producer.
Why?

Answer 16

Some light will miss the plant or the plant’s chloroplasts
Some light will be reflected by the cuticle
Some light has the wrong wavelength to be absorbed by the chlorophyll

Question 17

Approximately 10% of energy is passed from one trophic level to the next.
Why?

Answer 17

Some parts of the organisms are not eaten
Some parts are not digested and absorbed - they are egested as faeces
Some materials are respired to release energy which is used for muscle contraction, cell division, movement of molecules

Question 18

What is an ecosystem?

Answer 18

The system or area where organisms interact with their physical environment.

Question 19

What are the advantages of using pyramid of biomass over a pyramid of numbers?

Answer 19

Because they are a more accurate way of looking at the relative amounts of organisms

Question 20

What is locking in?

Answer 20

The process of fossil fuels forming over millions of years. The living things do not decay properly after death due to the conditions of the soil.

Question 21

What are three ways carbon dioxide is released into the air?

Answer 21

Respiration of plants
Respiration of animals
Combustion of fossil fuels

Question 22

What is the enhanced greenhouse effect?

Answer 22

Any extra greenhouse effect caused by human activity

Question 23

What gases cause the greenhouse effect? Name 5.

Answer 23

Water vapour
Methane
Carbon dioxide
Nitrous oxide
CFCs

Question 24

When solar radiation passes through the clear atmosphere what happens to it?

Answer 24

Some solar radiation is reflected by the atmosphere and earth’s surface
Some of the infrared radiation is absorbed and re-emitted by the ghg molecules
Surface gains more heat and infrared radiation is emitted again
Some of the IR radiation is lost in space

Question 25

What is the human activity source of CO2?

Answer 25

Burning fossil fuels Deforestation slash and burn

Question 26

What is the human activity source of methane?

Answer 26

Bacteria in waterlogged paddy fields for rice cultivation Cattle produce large volumes of methane in their digestive system Bacteria in anaerobic conditions

Question 27

What is the human activity source of nitrous oxides?

Answer 27

Burning fossil fuels

Question 28

Where did CFCs come from and why were they banned?

Answer 28

They were in fridges and freezers and were used as a solvent in aerosols They were banned in the 1990s because they were blamed doe the hole in the ozone layer.

Question 29

What are the potential effects of global warming?

Answer 29

Melting of polar ice caps Sea level rise Increased extreme weather events Change in crops Spread of disease

Question 30

Describe the process of decomposition in the nitrogen cycle.

Answer 30

Protein in dead plants and animals is broken down. Ammonia is released into the soil

Question 31

Describe the process of nitrogen fixation in the nitrogen cycle.

Answer 31

Nitrogen gas is converted into ammonia in bacteria which is used to make proteins, when the bacteria die their proteins decompose, releasing ammonia back into the soil.

Question 32

Describe the process of nitrification in the nitrogen cycle.

Answer 32

Ammonia is converted into nitrites, and nitrites into nitrates.

Question 33

What microorganisms are involved in nitrogen fixation?

Answer 33

Nitrogen fixing bacteria

Question 34

What microorganisms are involved in nitrification?

Answer 34

Nitrifying bacteria

Question 35

Describe the process of denitrification.

Answer 35

Nitrates are converted to nitrogen gas. Denitrification reduces the amount of nitrate in the soil and therefore makes the soil less fertile.

Question 36

Where do some nitrogen fixing bacteria live?

Answer 36

In small structure - nodules - on the roots of legume plants

Question 37

Why do farmers grow leguminous plants in rotation with other crops?

Answer 37

Because when the nitrogen fixing bacteria living on them decompose they make the soil much more fertile by releasing ammonia which can be converted into nitrates. Also the farmers cam sell, the produce still.