B16+B17

Question 1

Plant’s biomass

Answer 1

The mass of living material. These are biological molecules formed when producers such as green plants or algae produce glucose by photosynthesis, with some glucose used to make other biological molecules.

Question 2

Excretion

Answer 2

Processes that get rid of the waste products of chemical reactions e.g. sweating, urination and breathing out

Question 3

Decay importance in cycle

Answer 3

1) Living things are made of materials they take from the world around them e.g. plants turn elements like carbon, oxygen and hydrogen from the soil and the air into the complex compounds(carbohydrates, proteins and fats) that make up living organisms. These get passed up the food chains.
2) These materials are returned to the environment in waste products, or when the organisms die and decay.
3) Materials decay because they’re broken down(digested) by microrganisms, which occurs faster in moist, aerobic(oxygen rich) conditions where microrganisms are more active.
4) Decay returns mineral ions(which plants need to grow) back into the soil.

Question 4

Biodiversity

Answer 4

Variety of different species of organisms on Earth, or within an ecosystem

Question 5

Importance of high biodiversity

Answer 5

Ensures ecosystems are stable as different species depend on each other for shelter and food.
Different species can help maintain the right physical environment for each other(the acidity of the soil).

Question 6

How do humans produce more waste

Answer 6

Water - Sewage and toxic chemicals from industry can pollute lakes, rivers and oceans, affecting the plants and animals relying on them for survival, with the chemicals used on land(fertilisers, pesticides and herbicides) washed into water.
Land - We use toxic chemicals for farming(e.g, pesticides and herbicides), also burging nuclear waste underground and dumping a lot of household waste in landfill sites,
Air - Smoke and acidic gases released into the atmosphere can pollute the air e.g. sulfur dilxide can cause acid rain

Question 7

Greenhouse effect

Answer 7

Gases in the atmosphere act as an insulating layer which absorb most of the energy normally radiated out into space, and re-radiate it in all directions(including back towards the Earth). This increases the temperature of the planet.

Question 8

Temperature of the Earth

Answer 8

A balance between the energy it gets from the Sun and the energy it radiates back out into space

Question 9

Causes of deforestation

Answer 9

To clear oand for farming to provide more food
To grow crops from which biofuels based on ethanol can be produced

Question 10

How does destroying peat bogs affect the CO2 in the atmosphere?

Answer 10

Plants living in bogs don’t fully decay when they die, because there’s not enough oxygen, so the partly-rotted plants gradually build up to form peat and the carbon in the plants is stored in the peat instead of being released into the atmosphere. Peat pogs are often drained so the area can be used as farmland, or the peat is cut up and dried to use as a fuel, and when the peat is drained, it comes into contact with air and some microrganisms start to decompose it. When these microrganisms respire, they use oxygen and release CO2.
CO2 is also released when peat is burned as a fuel.

Question 11

Bogs

Answer 11

Areas of land that are acidic and waterlogged

Question 12

Pressures affecting how biodiversity is maintained

Answer 12

1) Protecting biodiversity costs money e.g. money to keep a watch on whether the programmes and regulations designed to maintain bipdiversity are followed,
2) Protecting biodiversity may come at a cost to local people’s livelihood as reducing deforestation can leave people on the tree-felling industry unemployed.
3) Land is in such high demand that previously untouched land with high biodiversity has to be used for development.

Question 13

Peat bog use

Answer 13

Drained for farming
Dried and used as a fuel
Can be used to produce compost for gardens or farms to increase food production

Question 14

Convection

Answer 14

The movement caused within a fluid as the hotter, less dense material rises and colder, denser material sinks under the influence of gravity(transfer of heat)

Question 15

Disadvantages of conservation, breeding and sustainable forestry programmes

Answer 15

Often expensive and difficult to regulate
It’s difficult to maintain biodiversity while preventing crops being overrun with pests and weeds, which would affect food security for the human population

Question 16

How microrganisms in the soil recycle carbon from the leaves

Answer 16

1) Decay/decomposition of leaves
2) Respiration by microrganisms/decomposers causes the microrganisms to release carbon dioxide.
3) The carbon dioxide is used in photosymthesis(for new plant growth)

Question 17

How are human activities polluting rivers, lakes and seas

Answer 17

1) Increase in world population
2) Need to produce more food for world’s population
3) Increasing demand for products(energy
4) Buildup of waste products
Consequence of the above is organisms living in rivers/lakes/seas are harmed/die

Question 18

How is an increase in the world population causing the pollution of rivers, lakes and seas?

Answer 18

Sewage(released into rivers/lakes/seas):
Causes algae to grow
Algae block light, causing plants to die and decompose, leading to lack of oxygen in the water, sewage could contain pathogens

Question 19

How does the need to produce more food for the world’s population cause pollution of rivers, lakes and seas:

Answer 19

Fertilisers(used on farms to increase crop yield, leach into rivers/lakes/seas)

Herbicides/pesticides(used on farms to increase crop yield, run i to rivers/lakes/seas):

Question 20

How does an increasing demand for products/energy lead to pollution of rivers, lakes and seas:

Answer 20

1) Toxic chemicals run into rivers/lakes/seas:
From factories or power stations
Build-up in food chains
Chemicals may cause mutations
Radiation leaks from nuclear power stations
Oil spills from extraction/rigs/tankers in ocean
Acid rain formation
Acidification of lakes
Increases carbon dioxide emissions cause acidification of oceans

Question 21

How does the buildup of waste products cause pollution of rivers, lakes and seas:

Answer 21

Litter/plastics(thrown in rivers/lakes/seas):
Plastics consumed/plastics build up in the stomach/plastics get stuck around the beaks
Most plastics are not biodegradable
Build-up of microplastics in water animals

Question 22

How humans rely on other species to survive

Answer 22

We rely on photosynthetic organisms to produce oxygen, without which we cannot respire
We rely on pollinator species such as bees to pollinate our food crops
We rely on many plant species for medicine

Question 23

How pesticides and herbicides affect biodiversity?

Answer 23

These chemicals can’t be broken down by organisms
Bioaccumulation
Biomagnification

Question 24

Bioaccumulation

Answer 24

The increase in concentration of a toxic chemical in a particular organism over time

Question 25

Biomagnification

Answer 25

The increase in concentration of a toxic chemical the higher the organism is in the food chain, leading to death or failure to breed.

Question 26

Cause/source of pesticides and herbicides

Answer 26

Sprayed on crops to prevent damage by insects and growth of weeds. Runoff occurs from agricultural land if these toxic chemicals are applied in too high a concentration. These toxic chemicals can also get into the soil.

Question 27

Untreated sewage(source)

Answer 27

Lack of sewage treatment plants in inhabited areas

Question 28

How untreated sewage affects biodiversity

Answer 28

Sewage provides a good source of food for bacteria which increase rapidly, depleting the oxygen dissolved in the water(as they respire aerobically). This lack of oxygen eventually results in the death of aquatic organisms such as fish and aquatic invertebrates(eutrophication)

Question 29

Eutrophication

Answer 29

The death of aquatic organisms such as fish and aquatic invertebrates due to a lack of oxygen

Question 30

Fertiliser source

Answer 30

Runoff occurs from agricultural land if fertilisers are applied in too high a concentration, causing fertilisers to enter watercourses

Question 31

How fertilisers affect biodiversity

Answer 31

Fertiliser causes increased growth of algae and water plants. This algal bloom blocks sunlight so water plants on the bottom start to die, as does the algae when competition for nutrients becomes too intense.This leads to eutrophication and the death of many aquatic organisms

Question 32

Sources of water pollution

Answer 32

Toxic chemicals(pesticides and herbicides) Untreated sewage Fertilisers

Question 33

Sources of land pollution

Answer 33

Toxic chemicals(pesticides and hernicides) Discarded rubbish

Question 34

Discarded rubbish - affecting biodiversity

Answer 34

Landfill sites take up a lot of room - their creation often results in the destruction of natural habitats Toxic chemicals can spread from the waste into the soil. Much rubbish e.g. made from plastic, is non-biodegradable and remains in the environment for hundreds of years

Question 35

Air pollution impacts

Answer 35

Acid rain can damage the leaves, buds, flowers and roots of trees and other plants. It can make rivers and lakes too acidic, resulting in the deaths of certain aquatic organisms. It can also cause the leaching of minerals that are toxic to fish, such as aluminium, into lakes.

Question 36

How does the reintroduction of field margins and hedgerows in agricultural areas where far,ers grow only one type of crop help biodiversity?

Answer 36

A single crop - type(monocultures) can only support a low level of biodiversity. Hedgerows, as well as the wild flowers and grasses growing when field margins are created, support a high level of biodiversity

Question 36

Difficulties with protected food security

Answer 36

Land protected to maintain biodiversity could be used for farming Organisms seen as a threat by farmers(locusts and wolves) are killed to protect crops and livestock - affecting food chains/biodiversity