Chapter 36 - Human Influence On The Ecosystem

Question 1

What is monoculture?

Answer 1

The practice of the production of a single crop in a given area year after year.

Question 2

What is polyculture?

Answer 2

When more than one crop is grown in the same space at the same time.

Question 3

Name the negative impacts of large-scale monoculture.

Answer 3

• increased difficulty in nutrient recycling
• decreased crop yield
• increase artificial fertilisers
• leads to quicker build up of pests & diseases
• vulnerable to natural disasters
• lack of biodiversity

Question 4

What is intensive livestock production?

Answer 4

When many animals are kept in a small area for a high stocking rate.

Question 5

Name the advantages of intensive livestock production. (3)

Answer 5

• Farmers can easily monitor the land and protect the livestock
• produce from these farms has driven the cost of meat and poultry decreasing
• farming this way is more economical due to smaller spaces needed

Question 6

Name the negative impacts of intensive livestock production. (4)

Answer 6

• it can make animals more susceptible to diseases and infections
• farmers use antibiotics to prevent diseases, which leads to the evolution of bacteria and the rise of drug-resistant pathogens
• the animals are given growth hormones which can be passed on to humans who consume the meat
• negative impacts on the health and well-being of the animals kept in such strenuous conditions

Question 7

What is habitat destruction?

Answer 7

It is damage caused to an area that certain species live in, to the extent that the species can no longer survive in that area.

Question 8

What is a habitat?

Answer 8

An ecological environment that’s exhibited by a particular species of organisms. (Plants/animals/other)

Question 9

Name the reasons that lead to habitat destruction. (6)

Answer 9

Agriculture
Irrigation
Global warming
Fire
Natural disasters
Construction

Question 10

Name reasons of how we can reduce the causes of habitat destruction. (3)

Answer 10

• we can attempt to minimally impact an area with new construction by using existing farmland and by being extremely cautious with fire
• by promoting the use of renewable energy sources and finding alternatives to deforestation
• efforts can be made such as planting more trees

Question 11

What is deforestation?

Answer 11

It is the cutting down and removal of all/most of the trees in a forested area.

Question 12

Name the causes of deforestation. (6)

Answer 12

• More agricultural land needed to farm
• Space needed for development of towns/roads
• Areas cleared for mining & industrial development
• Wood needed for manufacturing of furniture/building materials/firewood
• Hunters sometimes burn trees to chase out animals but uncontrolled fires can destroy many trees
• Overgrazing can also be a cause

Question 13

Name the undesirable effects of deforestation. (5)

Answer 13

• leaching of soil increase (soil become infertile)
• less decomposing of organic materials also lead to infertile soils
• less photosynthesis occurs, so less CO2 is removed from the air causing global warming
• disruption of food chains and food webs
• a loss of income as fewer tourists will visit the area

Question 14

Name ways to reduce deforestation. (3)

Answer 14

• using alternative energy forms
• recycle paper and less use paper
• new trees should be planted

Question 15

What is famine?

Answer 15

It is the widespread scarcity of food caused by several factors.

Question 16

Name the problems that contribute to famine. (4)

Answer 16

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

Question 17

What is pollution?

Answer 17

It is the contamination of air/water/soil by substances that are harmful to living things.

Question 18

Name the sources and effects of water pollution. (5)

Answer 18

• industrial waste
• sewage & wastewater
• mining activities
• marine dumping
• accidental oil leakage

Question 19

Name the sources of land pollution. (5)

Answer 19

• increase in urbanisation
• increase in agricultural land
• domestic waste
• agricultural activities
• industrial activites

Question 20

Name the effects of land pollutants on wildlife. (4)

Answer 20

• land pollution exterminates wildlife
• acid rain kills trees and other plant
• vegetation that provides food+shelter is destroyed, which can seriously disrupt nature
• pesticides can damage crops, kill vegetation and poison organisms.

Question 21

Name the undesirable effects of water pollution by sewage. (2)

Answer 21

• sewage is a source of disease
• sewage can cause eutrophication

Question 22

Explain the process of eutrophication.

Answer 22

Large amounts of organic matter in sewage are decomposed by aerobic bacteria.
Bacteria respire and reduce the amount of oxygen in the water.
Other aquatic organisms die or move away which reduced biodiversity.
A high content of nitrates, phosphates & ammonia are released into the water which then cause algae bloom.
The algae blocks/reduce light, preventing photosynthesis in submerged aquatic plants so they start to die.
Decomposers rapidly increase to use dead plants as food during decomposition and bacteria start using up all the available oxygen during respiration.
Other aquatic organisms start to die or migrate.

Question 23

Explain sewage as a source of dangerous chemicals & gases.

Answer 23

Sewage contains toxic chemicals and detergents which build up in food chains and become more concentrated from link to link.
Anaerobic bacteria increase in sewage to digest organic faeces and then produce methane (which is a greenhouse gas) and hydrogen sulphide which has a very unpleasant smell.

Question 24

What is pesticides?

Answer 24

It are chemical substances that are used for destroying organisms harmful to cultivated plants or animals.

Question 25

Name the undesirable effects of water pollution by pesticides. (5)

Answer 25

- they are non-biodegradable so the will remain in the environment - they may be soluble in oils and fatty tissue so they become part of living organisms - they can be washed into water sources and become part of the food chains of fish - the become more concentrated in each successive link of food chains causing biomagnification - they can cause serious harm to organisms in high concentration

Question 26

What is recycling?

Answer 26

It is the process of converting waste materials into reusable objects to prevent waste of becoming potentially harmful materials.

Question 27

Name how you can do recycling to reduce pollution. (3)

Answer 27

- keep objects in tact when recycling them - save returnable cans/bottles to make some money back - know the things that you can’t recycle.

Question 28

Name some alternatives to using large amounts of fertiliser.

Answer 28

- use nitrogen fixing crops to add nitrates to the soil - use crop rotation by planting different crops which need different nutrients each year - use less artificial inorganic fertiliser and more organic fertilisers

Question 29

What is acid rain?

Answer 29

Rain or any form of precipitation that is unusually acidic.

Question 30

What causes acid rain?

Answer 30

It is caused by emissions of sulphur dioxide and nitrogen oxide which react with water molecules in the atmosphere to produce acids.

Question 31

Name the effects of acid rain on human structures.

Answer 31

Acid rain is corrosive, so marble & limetone buildings lose their shapes and features or they crumble and break. It also corrodes metals and causes rusting.

Question 32

Name the effects of acid rain on soil.

Answer 32

Soils become acidic which can cause the leaching of minerals out of the soil which decreases soil fertility. Acidic soils affect microorganisms which cause less decomposition.

Question 33

Name the effects of acid rain on water.

Answer 33

Acid rain dissolves and washes out aluminium and mercury from the soil which can end up in water sources and poison aquatic life. If the pH of water bodies become too acidic, it kills the organisms living in it, which affects the entire food chain. Damage is caused to groundwater and drinking water.

Question 34

Name the effects of acid rain on plants.

Answer 34

Acid rain dissolve minerals like Mg, Ca and K from leaves, which cause the leaves to turn brown and fall off. Aluminium also damage fine root hairs so they aren’t able to absorb water + nutrients.

Question 35

Name some measures to reduce acid rain.

Answer 35

Emissions form vehicle exhausts can be cleaned up by catalytic converters. Lime / limestone can be added to lakes to neutralise acids. They use of fossil fuels must be limited. Coal can be crushed and washed before being burned, which reduces sulphur.