P2 4d human influences

Question 1

what are reasons for human population growth?

Answer 1

• improved tech leads to increase in birth rate

- improved medicine, hygiene and health care

Question 2

what are the pollutants of water pollution?

Answer 2

• toxic chemicals
• untreated sewage
• fertilisers

Question 3

what is the source of toxic chemicals in water?

Answer 3

• pesticides and herbicides sprayed on crops.

- runoff occurs from agricultural land if these toxics chemicals are applied in too high a concentration

Question 4

what is the cause of untreated sewage in water?

Answer 4

lack of sewage treatment plants in inhabited areas, meaning sewage runs or is pumped into watercourses

Question 5

what is the source of fertilisers in water?

Answer 5

runoff occurs from agricultural land is fertilisers are applied in too high a concentration, entering water-sources

Question 6

how does toxic chemical effect biodiversity?

Answer 6

• they can’t be broken down by organisms
• can be absorbed by aquatic plants or invertebrates and can build up in the tissues of these organisms overtime, causing bioaccumulation
• at each stage of the food chain the chemicals build up which can lead to dangerously toxic levels, causing death or failure to breed, this is biomagnification

Question 7

how does untreated sewage effect biodiversity?

Answer 7

It provides a good source of bacteria which increases rapidly, depleting the oxygen dissolved in water because aerobic respiration
the lack of oxygen results in the death of aquatic organisms such as fish and aquatic invertebrates, this is eutrophication

Question 8

how do fertilisers effect biodiversity?

Answer 8

causes increased growth of algae and water plants, causing algal bloom, which blocks sunlight to water plants, causing death
eventually the algae also dies while competing for nutrients
dead plants and algae are a good food source for bacteria
leads to eutrophication

Question 9

what are the pollutants of land pollution?

Answer 9

• toxic chemicals

- discarded rubbish

Question 10

what is the source of toxic chemicals on land?

Answer 10

when sprayed on to crop these toxic chemicals also get into the soil

Question 11

how does toxic chemical effect biodiversity on land?

Answer 11

• can’t be broken down
• causes bioaccumulation
• causes biomagnification

Question 12

how does discarded rubbish effect biodiversity?

Answer 12

landfill sites take up a lot of room, causing destruction of natural habitats
toxic chemicals can spread from the waste into the soil
non-biodegradable things stay in the environment for hundreds of years

Question 13

what is the source of discarded rubbish on land?

Answer 13

household waste that can’t be recycled is buried in landfill series

Question 14

what is the pollutant of air pollution?

Answer 14

sulphur dioxide and nitrogen oxides

Question 15

what is the source of sulphur dioxides and nitrogen oxides in air?

Answer 15

combustion of fossil fuels that contain sulphur impurities creates sulphur dioxide
nitrogen oxides are also produces in combusting fossil fuels
they react with oxygen and dissolves in rainwater to produces dilute sulphuric acid and nitric acid, making acid rain

Question 16

how does effect sulphur dioxides and nitrogen oxides biodiversity?

Answer 16

acid rain can damage the leaves, buds and flowers of plants
it can make rivers and lakes too acidic, causing death in aquatic organisms
cause leaching of minerals that are toxic to fish into lakes

Question 17

what is a greenhouse gas?

Answer 17

gas that absorbs infrared radiation from the sun so it remains trapped in the earths atmosphere

Question 18

why are greenhouse gases important?

Answer 18

to ensure it is warm enough for life

Question 19

what are the important green house gases?

Answer 19

water vapour 
carbon dioxide
methane 
nitrous oxides 
CFCs

Question 20

what human activities have increased levels of carbon dioxide and methane in the atmosphere?

Answer 20

• CO2 is produced by the combustion of fuels

- methane by Cattle and rice paddy fields

Question 21

how does the greenhouse effect work?

Answer 21

• sun emits rays that enter the earths atmosphere
• heat bounces back from the surface
• some heat is reflected back out
• some heat is absorbed by greenhouse gases

Question 22

what are the consequences of global warming?

Answer 22

• ocean temp increasing
• increasing temperatures
• changes in or loss habitats
• decreases biodiversity
• increases migration
• increased spread of pests and disease

Question 23

what is evidence for global warming?

Answer 23

• scientific consensus that human actives are largely responsible for most recent warming
• predictions

Question 24

what is deforestation?

Answer 24

clearing of trees on a large scale

Question 25

why is deforestation happening?

Answer 25

being cleared for the land to be used in a different way - building - grazing land - planting of monocultures

Question 26

what are the effects of deforestation?

Answer 26

- extinction / loss of biodiversity - soil erosion - flooding - increased carbon dioxide in atmosphere - disturbance of the water cycle

Question 27

what is the consequence of extinction / loss of biodiversity?

Answer 27

- forest habitats have lots of biodiversity and as a habitat is destroyed, it causes the loss of large numbers of plant and animal species - many of them are only found in one area and will become extinct

Question 28

what is the consequence of soil erosion?

Answer 28

- tree roots help stabilise the soil, preventing erosion - trees will take up nutrients and minerals - without trees they will remain unused in the soil, so washed away into rivers and lakes (leaching) - loss of soil nutrient is permanent makes it difficult to regrow things

Question 29

what is the consequence of flooding?

Answer 29

- without trees the topsoil will be loose and unstable so will be easily washed away by rain increasing the risk of flash flooding and landslides

Question 30

what is the consequence of increased carbon dioxide in atmosphere?

Answer 30

- trees take in carbon dioxide - removes significant numbers of trees, less CO2 being removed - when areas are cleared, trees are burned which releases carbon dioxide

Question 31

what is the consequence of disturbance of the water cycle?

Answer 31

- when trees are grouped together the water released by transpiration leads to clouds and rainfall, so cutting them areas become drier due to less rainfall

Question 32

what is a population?

Answer 32

a group of organisms of one species, living in the same area at the same time

Question 33

what is a community?

Answer 33

multiple populations living and interacting in the same area

Question 34

what is a habitat

Answer 34

a place where an organism lives

Question 35

what is an ecosystem?

Answer 35

interaction between the community and the non living or abiotic parts of the environment