Humans and the environment

Question 1

How modern technology has resulted in increased food production

Answer 1

• Agricultural machinery (tractors) to be used in larger areas of land and improve efficiency
• Chemical fertilizers to increase yield
• Insecticides sprayed on crops to improve quality and yield
• Herbicides are sprayed to reduce competition with weeds
• selective breeding to improve production by crop plants and livestock, e.g. cattle, fish and poultry

Question 2

negative impacts to an ecosystem of large-scale monocultures of crop plants

Answer 2

• there is a low biodiversity as only few species can live where crop is growing.
• Lead to increase in population of organism that are pests of the crop
• Spraying chemicals such as insecticides will kill pests however also kill predatory insects and spiders that help reduce population of pest.

Question 3

negative impacts to an ecosystem of intensive livestock production

Answer 3

• Welfare issues for livestock, diseases can be easily spread amongst livestock as are crowded together.
• Reduction in biodiversity in areas where large amounts of land are used to graze cattle (as only grass is grown so in effect it becomes a monoculture)
• overgrazing can lead to soil erosion
• waste from intensive farming unit can pollute land and waterways

Question 4

social implications of providing sufficient food for an increasing human global population

Answer 4

-Unemployment due to reduced labour force in rural area

Question 5

environmental implications of providing sufficient food for an increasing human global population

Answer 5

• Increased carbon emissions cause global warming

- Air pollution from factories as countries industrialise and exploit resources

Question 6

economic implications of providing sufficient food for an increasing human global population

Answer 6

• Higher energy prices as sources are depleted

- The gap between rich and poor becomes more evident.

Question 7

problems which contribute to famine

Answer 7

• unequal distribution of food
• drought and flooding
• increasing population and poverty

Question 8

reasons for habitat destruction

Answer 8

– increased area for food crop growth, livestock production and housing
– Damage habitats due to extraction of natural resources
– marine pollution

Question 9

How can humans have a negative impact on habitats

Answer 9

through altering food webs and food chains, humans can have a negative impact on habitats

Question 10

Undesirable effects of deforestation

Answer 10

• extinction
• loss of soil
• flooding
• increase of carbon dioxide in the atmosphere (trees take Co2 for photosynthesis, if trees are cut down less Co2 is taken and more Co2 give into atmosphere when trees are burnt.

Question 11

undesirable effects of deforestation on the environment

Answer 11

• Loss of biodiversity
• Loss of habitat
• Loss of hiding place for prey from predators
• Soil erosion ( Tree roots hold soil in place, without them rain can easily wash soil away, Trees intercept rain drops as they fall, without them rain hits harder on ground and soil is loosened and washed away, Trees absorb water from soil without trees less water is absorbed and more runs off surface of land causing soil erosion and flooding)
• Global warming

Question 12

sources and effects of pollution of land and water

Answer 12

rivers, lakes and the sea are affected by:

• insecticides
• herbicides
• nuclear fall-out

Question 13

sources and effects of pollution of water

Answer 13

rivers, lakes and the sea are affected by:

• chemical waste
• discarded rubbish
• untreated sewage
• fertilisers

Question 14

sources and effects of pollution of the air by methane and carbon dioxide

Answer 14

• Source of methane is cattle farming, rice fields. Methane is a greenhouse gas that contributes to enhanced green house effect (increase in greenhouse effect caused by increase in Co2 and Methane in atmosphere), causing climate change.
• Sources of Co2 are When fossil fuels are burnt or trees are burnt. Co2 is a greenhouse gas that contributes to enhanced green house effect, causing climate change.

Question 15

process of eutrophication of water

Answer 15

1. increased availability of nitrate and other ions (Excessive nutrients from fertilizers, run of from land to water, and untreated sewage)
2. increased growth of producers (Aquatic plants grow rapidly)
3. increased decomposition after death of producers (rapid growth of Algae)
4. increased aerobic respiration by decomposers (Growth of Algae prevents sunlight from entering water, thus oxygen levels fall)
5. reduction in dissolved oxygen (As decomposition rate increases due to aerobic respiration of decomposers reducing dissolved oxygen)
6. death of organisms requiring dissolved oxygen in water ( as there is a reduction in dissolved oxygen in water)

Question 16

effects of non-biodegradable plastics in the environment (both aquatic and terrestrial ecosystems)

Answer 16

Plastics are non-biodegradable thus decomposers cannot break them down.

• Burning of plastic releases toxic gases
• Dangerous to other organisms; Turtles may mistake plastic bags for jelly fish and continually eat them, it gradually collects in their stomach as their enzymes cannot break them down, thus cannot eat real food and eventually die.
• Animals get trapped inside of plastic containers, may get plastic cords or bags wrapped around their bodies, which can kill them.

Question 17

causes and effects on the environment of acid rain

Answer 17

Burning of fossil fuels causes release of sulphur dioxide and nitrogen dioxide which mixes with water to form nitric and sulphuric acid

• Causes infertile soil
• Causes acidified water in lakes that kills aquatic life
• Increased risk of asthma attacks and bronchitis in humans

Question 18

measures that are taken to reduce sulfur dioxide pollution and reduce the impact of acid rain

Answer 18

• Changing power stations from coal and oil to renewable resources
• Using SCRUBBERS in power stations, removing sulfur dioxide from them
• Using catalytic converters in car exhausts to convert nitrogen oxide into harmless nitrogen

Question 19

how increases in carbon dioxide and methane concentrations in the atmosphere cause an enhanced greenhouse effect that leads to climate change

Answer 19

• As Carbon dioxide increases it traps more heat in the atmosphere
• As Methane increases is absorbs more heat increasing temperature of atmosphere
• This traps more infrared radiation which make atmosphere warmer leading to enhanced greenhouse effect, Thus resulting in climate change.

Question 20

negative impacts of female contraceptive hormones in water courses

Answer 20

Oestrogen (& Progesterone) taking by women to stop producing eggs as a method of birth control. Some of theses hormones are excreted in women urine and into waterways in sewages. Fish and other animals (molluscus) that live in water can be affected by these hormones. As:

• reduced sperm count in men (male fish)
• feminisation of aquatic organisms (Male fish can change sex and become female fish)

Question 21

Sustainable resource

Answer 21

one which is produced as rapidly as it is removed from the environment so that it does not run out

Question 22

Sustainable development

Answer 22

as development providing for the needs of an increasing human population without harming the environment

Question 23

sustainable development requires

Answer 23

– management of conflicting demands

– planning and cooperation at local, national and international levels

Question 24

the need to conserve non-renewable resources, limited to fossil fuels

Answer 24

Fossil fuel is a unrenewable fuel source that takes long time to produce

Question 25

How forests and fish stocks can be sustained?

Answer 25

• education
• legal quotas
• re-stocking

Question 26

products can be reused or recycled

Answer 26

paper, glass, plastic and metal can be re used or recycled

• Paper involves:
  1. Collecting waste paper and shredding
  2. Make pulp using water and chemical
  3. Add glue to make a strong pulp
  4. Filter, make sure to remove printing ink
  5. Roll into thin sheets
• Glass: To make lime and soda
• Plastic : If we re use plastic it will reduce amount of fossil we have to use to make them again, thus saving of fossil fuel
• Metal: recycling metal save energy

Question 27

how sewage is treated to make the water that it contains safe to return to the environment or for human use

Answer 27

• Stone and sand filter to remove large impurities
• activated sludge process where air is pumped through sewage in which bacteria use to break down organic matter in water
• sludge is produced and used as starter culture for the next secondary treatment

Question 28

why organisms become endangered or extinct

Answer 28

• climate change
• habitat destruction
• hunting
• pollution
• introduced species

Question 29

Risks to a species if the population size drops, reducing variation

Answer 29

• loss in vigor (physical strength and good health)
• loss of individuals with resistance to diseases
• loss of individuals with resistance to change in environment
• loss of biodiversity

Question 30

how endangered species can be conserved

Answer 30

• monitoring and protecting species and habitats
• education
• captive breeding programmes
• seed banks

Question 31

reasons for conservation programmes

Answer 31

– reducing extinction
– protecting vulnerable environments
– maintaining ecosystem functions, nutrient cycling and resource provision, e.g. food, drugs, fuel and genes

Question 32

Importance of conservation

Answer 32

• Maintain biodiversity
• Maintain species biodiversity
• Maintain resources (forest)
• Restore habitat
• Conservation prevents animals and plants from extinction