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OCR A-Level Biology > Chap 24 - Populations & Sustainability > Flashcards

Chap 24 - Populations & Sustainability Flashcards

1
Q

Define abiotic factor

A

non-living components of an ecosystem (eg. light intensity, temperature, pH, O2 availability)

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2
Q

Define biotic factors

A

living components of an ecosystem (eg. disease, competition, predation)

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3
Q

Define limiting factor

A

factor that limits the rate of a process - environmental resource/constraint that limits population growth

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4
Q

Define carrying capacity

A

the maximum population size that an environment can support

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5
Q

Give 3 examples of limiting factors

A

competition, disease, build-up of toxic by-products of metabolism

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6
Q

Define migration

A

the movement of members of a species to a different environment

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7
Q

Define emigration

A

movement of individual organisms AWAY from a particular area

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8
Q

Define immigration

A

movement of organisms INTO a particular area

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9
Q

Define density independent factors

A

factors that have an effect on the whole population regardless of its size

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10
Q

State 3 examples of density independent factors

A

earthquakes, volcanic eruptions, fires

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11
Q

Define intraspecific competition

A

competition within members of the same species

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12
Q

Define interspecific competition

A

competition between organisms of different species

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13
Q

Give 4 examples of what organisms might compete for

A

food, water, space, light (plants)

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14
Q

Describe competition exclusion

A

where two species competing for limited resources, the one that uses the resource more effectively will ultimately eliminate the other

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15
Q

Explain the competition exclusion principle

A

when one species is better adapted it will outcompete the other - leads to decline in less-well adapted species until it can no longer exist

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16
Q

Explain the fluctuations caused by intraspecific competition

A
  1. when resources are plentiful, all organisms have enough to survive and reproduce = increase in population size
  2. there are more individuals sharing resources, they become limited and not enough for all organisms to survive.= decrease in population size
  3. less competition means less organisms competing for same resources, more organisms survive and reproduce = population increase
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17
Q

Define predation

A

where an organism kills and eats another organism

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18
Q

Describe an explain the general pattern shown in predator-prey cycles

A
  • increase in prey population provides more food for predators = more survive and reproduce = predator population increases
  • increased predator population eats more prey = decline in prey (death rate > birth rate)
  • reduce prey population can’t support predator population, intraspecific competition for food increases = decrease in predator population
  • reduce predator number = less prey being killed so more prey survive and reproduce = population increases
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19
Q

Define conservation

A

maintenance of biodiversity through human action or management

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20
Q

Define preservation

A

protection of an area by restricting or banning human interference - ecosystem is kept in its original state

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21
Q

Give 3 examples of conservation

A
  • controlled grazing of fens
  • controlled burning of forest (halts succession and increases biodiversity)
  • zoos
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22
Q

Give 3 examples of preservations

A
  • banning human development in certain areas
  • ban visitation in newly discovered areas
  • marine conservation zones
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23
Q

Define reclamation

A

process of restoring ecosystems previously damaged/destroyed

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24
Q

Give social arguments for the importance of conservation

A
  • people using natural beauty of wild ecosystems for activities (eg. bird-watching, cycling, climbing)
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25
Q

Give economic arguments for the importance of conservation

A

provides resources that humans need to survive to provide an income eg. medicinal drugs, food, clothes that can be traded

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26
Q

Give ethical arguments for the importance of conservation

A

all organisms have the right to exist and most play a role within their ecosystem. we have moral responsibility for future gens to conserve natural ecosystems

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27
Q

What is a sustainable resource

A

renewable resource that is being economically exploited in a way that they won’t diminish or run out

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28
Q

What are 5 aims of sustainability

A
  • preserve environment
  • ensure resources for future generations
  • allow humans to live comfortable
  • enable LEDCs to develop through exploiting natural resources
  • create more balance between LEDCs and MEDCs
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29
Q

What are examples of sustainability

A

reusing and recycling existing resources

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30
Q

What is coppicing?

A

cutting a tree trunk close to the ground creating multiple smaller trunks from one

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31
Q

What is pollarding

A

similar to coppicing but the trunks are cut higher to prevent deer and other animals from eating new shoots

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32
Q

What are examples of large scale timber production

A
  • selective cutting (only large trees)
  • replanting
  • distance trees
  • manage pests and pathogens
  • leave areas for indigenous people to use
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33
Q

What are negative implications of large scale timber production

A
  • soil vulnerable to erosion
  • soil minerals reduced as washed away
  • habitats destroyed
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34
Q

Explain fishing

A
  • as global pop. increases, demand for food increases
  • fish is valuable source of protein
  • overfishing has impacted fish pop. sizes
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35
Q

What are fishing quotas

A

limit the number of fish caught by species
- if they are exceeded = fined

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36
Q

Why do fishermen use large mesh nets

A

to allow immature fish to escape so only mature fish are caught - allows them to reproduce and mature healthily

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37
Q

Why are fishing months limited

A

to protect breeding seasons. eg. red snapper can only be caught in the gulf of mexico between May and June

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38
Q

What is fish farming

A

allows high supply of fish without affecting wild species population sizes

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39
Q

Where is the Terai region?

A

Southern Nepal

40
Q

How wide is the Terai region

A

25-30km

41
Q

How are the Terai lowlands defined?

A

by a belt of well watered floodplains

42
Q

Where does the Terai region stretch from?

A

from the Indian border in the south to the slopes of the Bhabhar and Siwalik mountain regions in the north

43
Q

The land of the Terai region is ___, and is the ______ of the country.

A
  • fertile
  • main agricultural region
44
Q

What are people engaged in?

A

farming, a range of trades, industries and services

45
Q

Why are natural resources at risk of being overused?

A

due to high population density

46
Q

Describe the atmosphere of the region

A
  • hot and humid in summer months
  • fertile soil rich in plant nutrients
  • extreme biodiversity - many subtropical plants (including bamboo, pipal)
  • larges areas of thick forest where animals (eg. bengal tiger, sloth bear and Indian Rhinoceros) can be found
47
Q

What is the Terai region important for?

A
  • millions of people depend on the forests for their livelihood
  • important source of national income
48
Q

What has poverty and corruption done to the area?

A
  • cleared larges areas of forest for agriculture/sell timber
49
Q

What has the removal of large sections of forests caused

A

exacerbated effects of monsoon flooding - caused severe disruption to communities downstream

50
Q

What will happen is deforestation is left unchecked

A

there will only be small pockets left of forest - devastating for wildlife and the local population who rely on the forests for income

51
Q

State how the environment is being changed and describe the effects of this?

A
  • large areas of forest have been cleared
  • increased effects of monsoon flooding - affecting communities local communities
  • decreases biodiversity
  • devastates wildlife and human populations that rely on forests for income through tourism and harvesting wood for building/fuel
52
Q

What are the aims of sustainable forest management?

A
  • provide livelihood for local people
  • ensure conservation of the forest
  • provide Nepali state with considerable income for development
53
Q

How is the sustainable forest management being achieved?

A
  • national legislation
  • development of local community forestry groups
54
Q

What do local forestry groups do?

A
  • develop own operational plans
  • set harvesting rules
  • set rates and prices for products
  • determine how surplus income is distributed or spent
55
Q

What have local forestry groups done through the creation of cooperative networks?

A
  • allows small forestry businesses can work effectively together eg. to gain Forestry Stewardship Council (FSC) certification
56
Q

What is the FSC?

A

an international standard which rewards sustainable forestry

57
Q

Name 6 successes for the community forestry groups?

A
  • increases area and density of forested regions
  • improved soil and water management
  • increased retail price of forestry products
  • increased employment and income
  • sustainable wood fuel sources contributing to ¾ of local household energy needs
  • securing biodiversity of forested areas
58
Q

Why does the Terai region require a range of management strategies?

A
  • to prevent damage of the ecosystem
59
Q

What management strategies are in place in the Terai region?

A
  • promoting production of fruit and veg in the hills and mountain regions to avoid intensification
  • improving irrigation facilities to enhance crop growth
  • multiple cropping (growing more than 1 crop on a piece of land)
  • growth of nitrogen-fixing crop to enhance soil fertility
  • growing crops varieties resistant to various soil, climatic and biotic challenges through the use of modern biotechnology
  • improve fertilisation techniques enhance crop yield
60
Q

What is a peat bog?

A

regions of spongy wet ground that contain decomposing vegetation

61
Q

What is undisputed peatland considered

A

a carbon sink

62
Q

Why is peatland considered a carbon sink

A

when it is dried and use as fuel, co2 is released into the atmosphere

63
Q

Why is it important to preserve peat bogs

A

they take thousands of years to form - preservation prevents further climate change

64
Q

What is peat used for?

A

as well as fuel - it is important for farmers and gardeners - it can improve soil structure and increase acidity

65
Q

Why does peat change the structure of the soil?

A

peat retains water when soil is dry - prevents excess water killing roots when soil is wet

66
Q

What is a major threat to farmers and gardeners ecosystems?

A

commercial peat extraction

67
Q

When does peat form

A

when plant material is inhibited from fully decaying by acidic and anarobic conditions - usually in wet and boggy conditions

68
Q

What is peat composed of?

A

mainly wetland vegetation (eg. mosses, sedges, shrubs)

69
Q

What are peatland plants adapted for

A

to grow and thrive in wet conditions with few nurtrients

70
Q

Why are peatlands ideal for many species

A
  • they support a wide range of insects - some act as a food source
  • lack of predators and human disturbance makes it ideal
71
Q

What is an example of a peatland ecosystem

A

lowland raised bogs - rare and threatened habitat

72
Q

In the UK, the area of undisturbed lowland raised bog has dropped by over ____ in last 100 years

A

90%

73
Q

What has the decline been caused by?

A

peat extraction, afforestation, agricultural intensification, including land drainage

74
Q

What is afforestation

A

the establishment of a forest or stand of trees in an area where there was previously no forest

75
Q

Why is it important to conserve peatlands

A

to maintain biodiversity, contribute to flood manage, carbon storage and erosion control downstream

76
Q

How can lowland bogs be conserved?

A
  • ensure they remain undisturbed
  • ditch blocking - allowing water table to rise to bog surface
  • remove seedling trees due to their high water requirement
  • controlled grazing to maintain biodiversity
77
Q

___ of the UK is classified as peat bog

A

10%

78
Q

Around ___ of these areas are in poor condition

A

80%

79
Q

What organisations work to preserve peat bogs?

A
  • the wildlife strusts
  • natural england
  • the royal society for the protection of birds (RSBP)
80
Q

Describe the ecosystem of the Masai Mara (1 mark)

A

Savannah / open grassland - open grassland with occasional shrub and trees (1)

81
Q

State 2 ways in which humans use the lands of the Masai Mara (1 mark)

A

tourism / ecotourism and farming / grazing (1)

82
Q

Explain how and why local Masai tribes have changed their style of farming in recent years (4 marks)

A

any four from: tribes of region were traditionally semi-nomadic (1); tribes of Masai have been restricted for certain defined areas / use areas around the reserve (1); means larger population density in these regions (1); land farmed more widely / more land used for agriculture (1); land farmed more intensely / greater reliance on fertilisers (1)

83
Q

The Masai Mara region receives around 300 000 visitors each year. State and explain the positive and negative impacts of this influx of people into the region (6 marks)

A

any six from: people bring economic input into the region (1); creates jobs / enables region to invest in infrastructure / technology / transport links / other relevant example (1); visitors see local tribes (1); allows for continuation of traditional culture pastimes / educates visitors about their traditional way of life (1); research is carried out on the Masai Mara (1); provides employment / improved facilities / better conversation approaches / ensuring maintenence of biodiversity (1); large visitor numbers requires infrastructure (1); can damage environment / uses natural resources / affects local habitat (1); visitors / safaris require transportation (1); leads to soil erosion / scares animals / increases pollution (1)

84
Q

Describe the ecosystem of the Terai region of Nepal (2 marks)

A

mixture of agricultural land, with dense forest regions (1); region is hot and humid in summer months / subject to monsoons (in rainy season) (1)

85
Q

State 2 ways humans use the Terai region of Nepal (1 mark)

A

any two from: growing crops / agriculture (1); forestry / felling timber for building resources / burning as fuel (1); tourism (1)

86
Q

Explain how sustainable forestry and agriculture practices are being used in the Terai region to maintain biodiversity while also meeting the needs of the local population (4 marks)

A

any four from: local community forestry groups have been established (1); to set harvesting rules / agreed prices for timber / reinvest profits for the benefit of the local population / enable small businesses to gain FSC certification (1). Sustainable forestry practice has: increased forested areas / forested density (1); therefore larger region available to support biodiverse ecosystem (1); improved water management / provided improved economic income to the region (1). Sustainable agriculture has: prevented further intensive agriculture in region (1); therefore retained biodiversity of less cultivated regions (1); improved irrigation of land / encouraged multiple cropping /planting of leguminous crops / planting of disease / climatic / biotic-factor resistant crops / improved fertilisation of land (1)

87
Q

Define environmentally sensitive ecosystems

A

ecosystems that are less resistant to changes than others

88
Q

What are the management techniques used in environmentally sensitive ecosystems

A
  • limiting the areas tourists can visit
  • controlling the movement of livestock
  • introducing anti-poaching measures
  • replanting of forests and native plants
  • limiting hunting through quotas and seasonal bans
89
Q

What are The Galapagos?

A

an archipelago of volcanic islands that sie up from the best of the Pacific Ocean 1000km west of Ecuador

90
Q

Why are The Galapagos of special interest

A

they have never been connected to the mainland - the original flora and fauna that reached the islands’ shores had to survive a crossing of hundreds of kilometers of ocean

91
Q

What types of animals live on the islands

A
  • majority are reptiles - one land mammal - the Galapagos rice rat
  • The Galapagos giant tortoise (Chelonoidis nigra) - grows to 150cm in length
  • the flightless cormorant (Pjalacrocoras harrisi) - reduced wings better for fishing underwater
  • marine iguana (Ambylyrhynchus cristatus) - contains advantageous mutation of being able to swim effectively
92
Q

How did the animals get to the islands?

A

by being washed away from mainland river banks/ floating on rafts of vegetation

93
Q

What are ectotherms and why are marina iguanas an example of this

A
  • the iguana appears black or dark grey allowing them to raise their body temp to approx. 36ºC before swimming in the cold sea where they forage for food
  • higher temp = longer they can forage
94
Q

What regions are present on The Galapagos

A
  • coastal zone - contains salt-tolerant species such as mangrove and saltbush
  • arid zone - contains drought-tolerant species such as cacti and carob tree
  • humid zone - contains dense cloud-forest - trees support populations of mosses and liverworts
95
Q

What measures have been put in place to protect living and non-living parts of the ecosystem

A
  • introduction of park rangers across the islands
  • limiting human access to particular islands, or specific parts of islands
  • controlling migration to and from the islands
  • strict controls over movement of introduced animals
96
Q
A

OCR A-Level Biology (16 decks)

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