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A-Level Biology > 24 Populations and Sustainability > Flashcards

24 Populations and Sustainability Flashcards

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1
Q

What is a population?

A

all organisms of one species in a habitat.

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2
Q

What is population size?

A

total number of organisms of one species in a habitat.

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3
Q

What can limiting factors be divided into?

A

Abiotic factors and biotic factors

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4
Q

What are examples of abiotic factors that can be also limiting factors?

A
  • Temperature
  • Light
  • pH
  • Availability of water or oxygen
  • Humidity
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5
Q

What are examples of biotic factors that can be also limiting factors?

A
  • Predators
  • Disease
  • Competition
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6
Q

What is carrying capacity?

A

The maximum stable population size of a species that an ecosystem can support.

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7
Q

How can migration affect population size?

A

1) Immigration- the movement of individual organisms into a particular area increases population size.
2) Emigration- the movement of individual organisms away from a particular area decreases population size.

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8
Q

What are density independent factors?

A

Density independent factors are factors that have an effect on the whole population, regardless of its size.
E.g: earthquakes, fires, volcanic eruptions, storms

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9
Q

What is interspecific competition?

A
  • Competitive exclusion principle : when organisms of different species compete with each other for the same resources e.g food, stronger species survive, niche overlaps - not the same niche
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10
Q

What is intraspecific competition?

A

When organisms of the same species compete with each other for the same resources.

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11
Q

What does conservation mean?

A

Conservation means the maintenance of biodiversity through human action or management.

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12
Q

What does reclaimation mean?

A

Reclaimation is the process of restoring ecosystems that have been damaged or destroyed.
E.g maintaining habitats

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13
Q

What is preservation?

A

Preservation is the protection of an area by restricting or banning human interference, so that the ecosystem is kept in its original.
- It is commonly used when preserving ecologically, archaeologically, or paleontologically sensitive resources, which are easily damaged or destroyed by disturbances.

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14
Q

What can the importance of conservation be divided into?

A

1) ECONOMIC- To provide resources that humans need to survive and to provide an income. E.g rainforest species provide medicinal drugs, clothes and food that can be traded. Other forests are used for the production of timber and paper.
2) SOCIAL- Ecosystems are enjoyable and attractive, used for activities such as bird-watching and walking
3) ETHICAL- Humans have a moral responsibility to conserve existing ecosystems.

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15
Q

What is a sustainable resource?

A

a renewable resource that is being economically exploited so it doesn’t diminish or run out.

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16
Q

What are the aims of sustainability?

A
  • preserve the environment
  • ensure enough resources are available for future generations
  • balance consumption of resources between MEDCs and LEDCs
  • enables LEDCs to develop
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17
Q

What technique is used to produce sustainable timber on a small scale?

A

Coppicing (more popular) and pollarding

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18
Q

What is coppicing?

A
  • Coppicing is a technique where a tree trunk is cut close to the ground.
  • New shoots form from the cut surface and mature.
  • This means new trees don’t need to be planted.
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19
Q

How does rotational coppicing maintain biodiversity?

A
  • Rotational coppicing maintains biodiversity as the trees never grow enough to block out the light.
  • Hence, succession can’t occur and more species can survive.
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20
Q

What is pollarding?

A

Pollarding is a technique when the tree trunk is cut higher up so deer and other animals can’t eat the shoots as they appear.

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21
Q

What technique is used to produce sustainable timber on a large scale?

A

Felling

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22
Q

What is felling?

A

Felling is when trees are cut down and destroyed.

23
Q

What are the disadvantages of felling?

A
  • Habitats destroyed
  • Soil minerals are reduced
  • Bare soil susceptible to erosion
  • Trees are important in maintaining nutrient levels through their role in carbon &nitrogen cycles.
24
Q

What other techniques are used to ensure sustainable timber production?

A

1) Plant trees an optimal distance apart to reduce competition. This results in higher yields as more wood is produced per tree.
2) Manage pests and pathogens to maximise yields.
3) Practise selective cutting- which involves removing only the largest trees

25
Q

What techniques are used to prevent overfishing?

A

1) Fishing quotas- they provide limits on numbers of certain species of fish that are allowed to be caught in a particular area.
2) Nets with different mesh sizes- large mesh sizes mean only mature fish are caught so immature fish can escape and continue breeding.
3) Allowing commercial and recreational fishing only at certain times of the year- this protects the breeding season of some fish species and allows the fish levels to increase back to a sustainable level.
4) Introducing fish farming to maintain supply of protein food

26
Q

What are the limitations of fishing quotas and mesh sizes?

A
  • Fish of wrong species/size are caught and are thrown back into the sea dead because the restrictions don’t allow fishermen to bring them ashore.
  • Nets which meet regulations could be overlapped so reduce the reported mesh size.
27
Q

What ecosystem is the Masai Mara National Reserve?

A

Savannah (grassland) ecosystem

28
Q

What is the Masai Mara National Reserve home to?

A

Wide range of mammals e.g Wildebeest, zebra, lions and cheetahs

29
Q

How did the Maasai people traditionally earn?

A
  • raising livestock such as cattle.
  • However, overgrazing removes vegetation and the risk of soil erosion increases.
  • Cultivation also occurred where natural vegetation was removed for cropland- this used up the nutrients in the soil.
30
Q

What solutions have been put into place in the Masai Mara National Reserve?

A
  • Conservation trusts are working with the Masai people to help them make money from their land through conservation and ecotourism projects rather than farming.
  • This allows the economic needs of the Masai people to be met while still allowing the area to be conserved.
  • Grazing is now limited to areas on the edge of the reserve.
31
Q

What is ecotourism?

A

Ecotourism is tourism directed towards natural environments, to support conservation efforts and observe wildlife.

32
Q

What are the key principles of ecotourism?

A
  • To ensure that tourism doesn’t exploit the natural environment or local communities.
  • To consult&engage with local communities on planned developments
  • To ensure that infrastructure improvements benefit local people
33
Q

What are the negative impacts of ecotourism?

A

Repeated use of hiking trails, or mechanised transport may contribute to soil erosion and other habitat changes.

34
Q

What caused black rhinos in the Masai Mara to decline?

A

Illegal poaching for rhino horns (used in traditional medicine)

35
Q

What does the conservation and protection programme in Masai Mara include?

A
  • Employment of reserve rangers

- Provision of communication equipment, vehicles and other equipment

36
Q

What is the Terai Arc?

A

The Terai Arc is a rich agricultural area on the border between Nepal and India.

37
Q

What is the ecosystem like in Terai Arc?

A
  • Hot and humid
  • Fertile soil that is rich in plant nutrients
  • Extreme biodiversity
  • Bengal tiger, sloth bear and Indian rhinoceros can be found
38
Q

What do the people in Terai Arc depend on?

A
  • The Terai Arc is an important source of national income- locals rely on the forests for income through tourism, and through harvesting wood for building products.
  • Due to poverty and large areas of forest have been cleared for agriculture or to sell timber.
39
Q

What did the removal of large parts of the forest lead to?

A
  • It has worsened the effects of monsoon flooding

- Caused severe disruption to communities downstream

40
Q

What is the aim of sustainable forest management?

A

The aim of sustainable forest management is to provide a livelihood for local people, ensure the conservation of forests, and provide the Nepali state with considerable income for general development.

41
Q

What management strategies does the Terai Arc use?

A
  • Improving irrigation facilities to enhance crop production
  • Multiple cropping
  • Growth of nitrogen-fixing crops to enhance fertility of soil
42
Q

What is a peat bog?

A

A peat bog is a region of wet, spongy ground that contains decomposing vegetation.

43
Q

What is undisturbed peatland?

A
  • Undisturbed peatland is a store of carbon dioxide and once dried it can be used as fuel.
  • Peat is also used by farmers who mix it with soil to improve soil structure and increase acidity.
44
Q

What are properties of peat?

A

Peat has favourable moisture-retaining properties so prevents excess water killing roots when the soil is wet.

45
Q

How does peat form?

A
  • Peat forms when plant material is inhibited from fully decaying by acidic and anaerobic conditions.
  • This normally occurs in wet or boggy areas, so peat is mainly composed of wetland vegetation such as mosses and shrubs.
46
Q

How are lowland bogs conserved?

A
  • Ensuring peat &vegetation is undisturbed and wet as possible.
  • Bogs are surrounded by ditches to allow water to run off, preventing flooding of nearby land.
  • Using controlled grazing to maintain biodiversity.
  • Removal of seedling trees from the area as they have a high water requirement.
47
Q

What is the Galapagos?

A
  • The Galapagos is an area of volcanic islands.
48
Q

What are the effects of human activities on the Galapagos Islands?

A
  • Explorers and sailors directly affected populations of some animals by eating them e.g Galapagos giant tortoise
  • Non-native animals introduced to the islands eat some native species.
  • Non-native plants introduced to the islands which compete with native plant species, causing their populations to decrease.
  • Fishing has caused a decrease in populations of some of the sea life.
49
Q

How is the impact of human activities on Galapagos Islands controlled?

A
  • Introduction of park rangers across the islands
  • Limiting human access to particular islands
  • Controlling mitigation to and from the islands
  • Strict controls over movement of introduced animals e.g pigs
50
Q

What are the effects of human activities on Antarctica?

A
  • Whaling in the waters surrounding Antarctica led to a decrease in whale numbers: now the Antarctic blue whale is critically endangered.
  • Seal hunting drove the Antarctic fur seal to the brink of extinction.
  • Visitors to Antarctica have contributed to pollution by dumping sewage into the sea.
  • Soil contamination
51
Q

How is the impact of human activities on Antartica controlled?

A

The Antarctic Treaty was established. Some of its provisions include:

  • Scientific cooperation between nations
  • Protection of the Antarctic environment
  • Conservation of plants and animals
  • Designation and management of protected areas
  • Management of tourism
52
Q

What are the effects of human activities on Snowdonia National Park?

A
  • Visitors go walking on the region’s footpaths which leads to the erosion of the footpaths and loss of soil from hillsides.
  • Soil which ends up in lakes can disturb the pH of the water causing knock on effects for wildlife.
  • Walkers can trample and destroy the sensitive vegetation.
53
Q

How is human impact controlled in Snowdonia National Park and the Lake District?

A
  • Conservation charities attempt to carry out regular repair and maintenance work on the paths and encourage regrowth of damaged vegetation.
  • Walkers are educated about the importance of sticking to paths and not taking short cuts.

A-Level Biology (41 decks)

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