B1.4 (Humans and their environment)

Question 1

What factor caused population to majorly increase in the 19th and 20th century?

Answer 1

Access to better healthcare allowed longer lives

Question 2

What are the negative impacts on resources by the large population?

Answer 2

• Non-renewable energy resources are being used up rapidly
• Raw materials are used up rapidly
• Land is urbanised (quarrys, roads, buildings) meaning less land for animals
• More waste is produced which causes more pollution

Question 3

Why are herbicides useful?

Answer 3

They inhibit the growth of weeds which reduces the competition for land, space, and nutrients meaning the useful plants can grow better

Question 4

Why are pesticides useful?

Answer 4

Pesticides kill insects and plant pathogens that feed and damage crops

Question 5

How do pesticides and herbicides harm the environment?

Answer 5

• They can stay in the soil for long periods of time
• They can be washed into rivers and lakes
• They can disrupt the natural foodchain with pollution or toxins

Question 6

How are fertilisers useful?

Answer 6

They supply extra nutrients to plants to increase the crop yield

Question 7

What is eutrophication?

Answer 7

Where minerals supplied by fertlisers are washed into waterways and cause the hyper neutrition of algae, which leads to a declining oxygen supply in the water making it uninhabitable for fish and other animals

Question 8

How does sewage pollute waterways?

Answer 8

Sewage contains high levels of minerals and so can cause eutrophication
It can also contain harmful pathogens to the water habitat

Question 9

How can waterways be polluted?

Answer 9

• Fertilisers
• Sewage
• Toxic chemicals

Question 10

What air pollutants do humans contribute to the atmosphere?

Answer 10

Smoke (incomplete combustion particulate)
Sulfur dioxide
Carbon dioxide
Methane

Question 11

Where does sulfur dioxide come from and what issues can it cause?

Answer 11

The combustion of fossil fuels with sulfur impurities eg coal

Can cause acid rain that damages buildings, lakes, and plants

Question 12

Where does methane come from and what issues can it cause?

Answer 12

Anaerobic decomposition of landfill waste

Greenhouse gas that contributes to global warming

Question 13

Why do people cut down trees?

Answer 13

• To provide timber as a fuel and material
• To create land for agriculture
• To create land for urbanisation
• To grow BIOLFUELS

Question 14

What are the impacts of deforestation?

Answer 14

• Reduces the rate at which carbon dioxide is ‘locked away’
• Decompostiion and burning releases carbon dioxide
• Biodiversity is reduced as habitats are destroyed
• Cows and rotting rice plants grown on land produce methane

Question 15

Why do we want to maintain biodiversity?

Answer 15

• A decrease in biodiversity could mean loss of organisms that could be helpful to us in the future
• As humans we have a moral obligation to preserve the world and habitat

Question 16

What is a peat?

Answer 16

Partially decomposed plants and organisms found in waterlogged bogs and fens that have been prevented from decomposing due to the anaerobic conditions and acidity of bog.

Question 17

How is peat useful?

Answer 17

• It locks up carbon dioxide in the partially decomposed organisms
• The large quantity of biomass means it is useful as a fuel
• It can be mixed with soil to improve the structure and acidity of soil

Question 18

Why would a gardener want ‘peat-free’ soil that uses sustainable alternatives to peat?

Answer 18

Although peat is useful, the extraction of it releases greenhouse gases and destroys habitats
When mixed with soil, the peat is no longer in anaerobic conditions and is able to decompose, releasing carbon dioxide

Question 19

What are the two main greenhouse gases that are increasing?

Answer 19

Methane and Carbon dioxide

Question 20

Why are carbon dioxide levels increasing?

Answer 20

• Humans are burning more fossil fuels to release energy
• Humans are cutting down forests
• Humans are destroying peat bogs

Question 21

Why are methane levels increasing?

Answer 21

• More cattle are being reared which release methane as part of their digestive system
• More rice fields are being grown that produce methane when they rot anaerobically
• More waste is produced that produces methane when it rots

Question 22

What can a global rise in temperature cause?

Answer 22

• Climate changes
• Melting ice caps and rising sea levels
• Loss in biodiversity as organisms fail to adapt
• Change in migration of animals
• Change in distribution of species

Question 23

What is the process of sequestration?

Answer 23

Carbon dioxide disolves into sea water

Phytoplankton in the water perform photosynthesis and trap the Carbon dioxide in their biomass

Question 24

How is ethanol produced to be used as the biofuel bioethanol?

Answer 24

Sugar is fermented with yeast in anaerobic conditions producing ethanol and carbon dioxide

In the fermentation of maize, amyase is used to break down the starch into sugar first

Question 25

What are disadvantages of using bioethanol as a fuel?

Answer 25

• Uses rainforest land
• Slow growth does not satisfy fuel demand
• Pure ethanol requires engine modification
• It can contribute to global warming if it releases more carbon dioxide than it absorbs
• Space could be used to grow food rather than fuel

Question 26

What is biogas?

Answer 26

Biogas is fuel produced by the gases (methane) created in the decomposition of animal waste

The carbon dioxide released when the gas is burnt is then absorbed by plants

Question 27

What factors affect biogas?

Answer 27

• More oxygen = more carbon dioxide, less methane
• Cooler than 32-35 = slower rate of biogas production
• Hotter than 32-35 = denatured enxymes and slower rate of biogas production

Question 28

How can too cool or too warm conditions be solved to produce efficient biogas?

Answer 28

Too cool = Bury / insulate the generator with thick walls

Too warm = Bury generator to keep cool in day and warm in night

Question 29

How can you improve the efficiency of a food chain?

Answer 29

Reduce the number of trophic levels an so reduce the amount of biomass and energy lost

Question 30

How can you reduce the amount of energy lost by an organism?

Answer 30

• Preventing the animal from moveing around (conserves energy)
• Keeping them in warm surroundings (preseerves energy that would have been used to maintain temperature)

Question 31

What are the negatives of factory farming?

Answer 31

• Reduced animal welfare
• Increased risk of injury
• Increased risk of disease

Question 32

What is Mycoprotein?

Answer 32

High protein food produced from biomass of the funghi Fusarium
High in protein, fibre and low in fat and cholesterol so it is healthy and can be used as an alternative to meat!

Question 33

How can mycoprotein be produced?

Answer 33

A small culture of Fusarium is added to a sterile broth of glucose syrup produced by plant starch by amylase enzymes in a fermenter
The syrup, ammonia, and air are continuously added over the course of six weeks to encourage the Fusarium to grow
The ammonia helps the production of proteins and there is a cooling spiral to keep the temperature consistent

After six weeks, the fungus has grown (doubling every 5 hours) and is harvested and purified at 65 degrees
and spun to dry with a centrifuge

Question 34

What does mycoprotein look like?

Answer 34

A solid yellow substance

It can be coloured and flavoured and added to foods

Question 35

What regulations are in place to encourage sustainable fishing?

Answer 35

• Fish quotas for countries and vessels which limit the amount of fish allowed to be caught
• Smaller size of mesh nets caught and larger holes meaning only mature fish are caught

Question 36

Who do people moniter food miles?

Answer 36

The lower the food mile, the shorter the distance the food has travelled and so the less negative impacts it has had on the environment through carbon dioxide emissions