B16/17

Question 1

What is biodiversity

Answer 1

Biodiversity is the variety of all the different species of organisms on earth, or within an ecosystem

Question 2

What does a greater biodiversity mean

Answer 2

A great biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment

Question 3

Why is it important to maintaining a large biodiversity

Answer 3

The future of the human species on Earth relies on us maintaining a good level of biodiversity. Many human activities are reducing biodiversity and only recently have measures been taken to try to stop this reduction

Question 4

Why are more resources used and why can this be a problem

Answer 4

Rapid growth in the human population and an increase in the standard of living mean that increasingly more resources are used and more waste is produced.
Unless waste and chemical materials are properly handled, more pollution will be caused

Question 5

How can pollution occur

Answer 5

• in water, from sewage, fertiliser or toxic chemicals
• in air, from smoke and acidic gases
• on land, from landfill and from toxic chemicals

Question 6

How does pollution affect biodiversity

Answer 6

Pollution kills plants and animals which can reduce biodiversity

Question 7

How do humans affect the land around them

Answer 7

Humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste

Question 8

What does the destruction of peat bogs mean

Answer 8

The destruction of peat bogs, and other areas of peat to produce garden compost, reduces the area of this habitat and thus the variety of different plant, animal and microorganism species that live there (biodiversity)

Question 9

What does the decay of burning peat release

Answer 9

Carbon dioxide into the atmosphere

Question 10

What is global warming

Answer 10

Levels of carbon dioxide and methane in the atmosphere are increasing, and contribute to ‘global warming’.

Question 11

How do people maintain biodiversity

Answer 11

• breeding programmes for endangered species
• protection and regeneration of rare habitats
• reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop
• reduction of deforestation and carbon dioxide emissions by some governments
• recycling resources rather than dumping waste in landfill

Question 12

What are producers

Answer 12

Producers are mostly plants and algae which transfer about 1 % of the incident energy from light for photosynthesis

Question 13

How much energy is transferred from each trophic level and how is energy lost

Answer 13

Only approximately 10 % of the biomass from each trophic level is transferred to the level above it
• not all the ingested material is absorbed, some is egested as faeces
• some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine
Large amounts of glucose are used in respiration

Question 14

What is food security

Answer 14

Food security is having enough food to feed a population.

Question 15

What are biological factors which are threatening food security

Answer 15

• the increasing birth rate has threatened food security in some countries
• changing diets in developed countries means scarce food resources are transported around the world
• new pests and pathogens that affect farming
• environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
• the cost of agricultural inputs
• conflicts that have arisen in some parts of the world which affect the availability of water or food

Question 16

How can food be used to feed people on earth

Answer 16

Sustainable methods must be found to feed all people on Earth

Question 17

How can the efficiency of food production be improved

Answer 17

Restricting energy transfer from food animals to the environment.
This can be done by limiting their movement and by controlling the temperature of their surroundings
Some animals are fed high protein foods to increase growth

Question 18

What is an ecosystem

Answer 18

An ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment

Question 19

What do organisms need to survive

Answer 19

To survive and reproduce, organisms require a supply of materials from their surroundings and from the other living organisms there.

Question 20

How do plants compete with eachother

Answer 20

Plants in a community or habitat often compete with each other for light and space, and for water and mineral ions from the soil.

Question 21

How do animals compete with eachother

Answer 21

Animals often compete with each other for food, mates and territory

Question 22

What is interdependance 🗿🗿

Answer 22

Within a community each species depends on other species for food, shelter, pollination, seed dispersal etc. If one species is removed it can affect the whole community

Question 23

What is a stable community

Answer 23

A stable community is one where all the species and environmental factors are in balance so that population sizes remain fairly constant

Question 24

What are examples of abiotic factors in a community (7)

Answer 24

• light intensity
• temperature
• moisture levels
• soil pH and mineral content
• wind intensity and direction
• carbon dioxide levels for plants
• oxygen levels for aquatic animals

Question 25

What are biotic factors (4)

Answer 25

• availability of food
• new predators arriving
• new pathogens
• one species outcompeting another so the numbers are no longer sufficient to breed

Question 26

What do all food chains begin with

Answer 26

Producers

Usually a green plant or algae that make glucose from photosynthesis

Question 27

How does a food chain work

Answer 27

Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.

Question 28

What are predators and prey and how do they interact

Answer 28

Consumers that kill and eat other animals are predators, and those eaten are prey.
In a stable community the numbers of predators and prey rise and fall in cycles

Question 29

How are materials cycled

Answer 29

Many different materials cycle through the abiotic and biotic components of an ecosystem

Question 30

Why are materials cycled

Answer 30

All materials in the living world are recycled to provide the building blocks for future organisms

Question 31

What does the carbon cycle do

Answer 31

The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis

Question 32

What does the water cycle fo

Answer 32

The water cycle provides fresh water for plants and animals on land before draining into the seas.
Water is continuously evaporated and precipitated

Question 33

How do microorganisms cycle nutrients

Answer 33

microorganisms cycle materials through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil

Question 34

What are the ideal conditions for decay

Answer 34

Warm temperatures
Wet
Lots of oxygen

Question 35

How do farmers make compost and how is it used

Answer 35

Gardeners and farmers try to provide optimum conditions for rapid decay of waste biological material.
The compost produced is used as a natural fertiliser for growing garden plants or crops

Question 36

What does anaerobic decay produce and how can this be used

Answer 36

Anaerobic decay produces methane gas.

Biogas generators can be used to produce methane gas as a fuel

Question 37

Equation to find population size

Answer 37

Total area/ area sampled x number of organisms of that species counted in sample