24 - Population and Sustainability Flashcards
1
Q
What are 4 examples of environmentally sensitive ecosystems?
A
- Antarctica 2. Snowdonia 3. Lake District 4. Galapagos Islands
2
Q
What is a population?
A
All the organisms of one species in a given area
3
Q
What is interspecific competition?
A
Competition for resources between different species
4
Q
What is intraspecific competition?
A
Competition for resources between members of the same species
5
Q
What pattern can intraspecific competition follow and what does this mean?
A
Can be cyclic, so greater resources mean a larger population
6
Q
What 2 things can interspecific competition affect?
A
- Distribution 2. Population of both species (both will usually decrease)
7
Q
What is carrying capacity?
A
The maximum stable population size of a species that an ecosystem can support
8
Q
What is population density?
A
Number of individuals per unit area of a chosen habitat
9
Q
What are the 4 most basic factors which affect population density?
A
- Birth rate 2. Death rate 3. Immigration rate to habitat 4. Emigration rate from habitat
10
Q
What 2 types of factors can affect population size?
A
- Density dependent 2. Density independent
11
Q
What are 3 examples of density dependent factors which affect population size?
A
- Predation 2. Disease 3. Competition
12
Q
What are 2 examples of density independent factors which affect population size?
A
Climate or natural disasters (earthquakes)
13
Q
What type of feedback are predation cycles an example of?
A
Negative feedback
14
Q
What are the 4 phases of a growth curve?
A
- Lag phase
- Log phase/ exponential phase
- Stationary phase
- Death phase
15
Q
What happens during the lag phase of a population growth curve?
A
there is only a very slow increase in population size; this is because little cell division is occurring as the microorganisms are adjusting to their new conditions,
e.g. changing their gene expression, carrying out transcription and
translation to make new carrier proteins and enzymes in order to uptake and metabolise the available nutrients; there will not be much energy available for cell division whilst this phase is occurring;
16
Q
What happens during the log phase of a population growth curve?
A
The population growth is increasingly steep
as the highest possible rate of cell division (e.g. binary fission of bacteria) occurs in this phase; there are no significant limiting factors yet: nutrients are still plentiful (so there’s not too much competition in the culture for these) and waste products have not yet built up to toxic levels; the population size may double every 20min (depending on species cultured) and rate of cell division far exceeds the rate of any cell death which may be occurring;
17
Q
During what phase of a population growth curve is maximum growth rate reached?
A
Log phase
18
Q
What happens during the stationary phase of a population growth curve?
A
The population size appears steady because there is an equal rate
of cell division and cell death; this is because limiting factors have started to have a significant effect (decreasing cell division rate but increasing cell death rate): one or more nutrients may be running low (increasing competition between cells) and waste products may now be at high enough concentration to be toxic to some cells;
19
Q
;)
A
:)
20
Q
During what stage of a population growth curve is carrying capacity reached?
A
Stationary phase
21
Q
What normally prevents populations from undergoing uncontrolled exponential growth?
A
Limiting factors
22
Q
What happens during the death phase of a population growth curve?
A
the population size decreases, as cell death rate now far
exceeds rate of cell division; one or more nutrients may have run out and accumulation of toxic waste is killing the cells; pH may have deviated from the optimum for the microorganisms’ enzymes, and heat released by their metabolism may mean that temperature increased so much that enzymes denature; eventually, no cells remain alive.
23
Q
What causes the death phase of a population growth curve?
A
A sudden change in the environment which lowers carrying capacity
24
Q
What is a limiting factor?
A
A limiting factor is something which stops a process or population increasing
any further.
25
What is the competitive exclusion principle?
No two species can occupy the same niche in the same habitat at the same time, so the species which uses resources more efficiently will ultimately eliminate the other
26
What happens when two species are competing for the same food source but one is better adapted than the other?
The less well adapted one is outcompeted and dies off
27
What is predation?
An interaction in which one organism kills another for food
28
What are the 3 stages of the effects of intraspecific competition on population size? DRAW GRAPH
1. When a resource is plentiful in a habitat, all organisms have enough to survive and reproduce, causing a rise in population size
2. Increased population means more organisms have to share available resources. As resources are now limited, the population decreases in size
3. Less competition exists due to smaller population, so growth occurs again
29
What type of competition is almost all predation?
Interspecific
30
What can happen if a predator or prey species does not evolve?
They could go extinct
31
Do all predator-prey relationships show the same pattern?
In general yes
32
What are the stages of a predator-prey relationship?
1. When predator numbers are low, the prey population increases as few are eaten by predators. Most prey offspring survive to breed themselves. Birth rate of prey is higher than death rate.
2. However, the increasing prey population now means there is more readily available food for predators. If the prey population has increased beyond its carrying capacity, some prey individuals may be weakened by lack of food (as intraspecific competition for limited food may lead to starvation) or by the increased presence of disease or pathogens spreading through the crowded population. These factors plus the high prey density mean that predators can catch prey more easily, with low energy expenditure themselves.
3. Predators therefore now have increased growth rates (enabling them to breed sooner), higher fertility and more offspring that survive to breed themselves. Hence, after a time delay, the previous increase in prey population is now followed by an increase in the predator population. The delay between the two will be longer in species where the predators are slow to reach maturity and have long gestation periods: it could then take several years before an increase in prey actually translates to bigger predator population.
4. Now the predator population is increasing (with their birth rate higher than their death rate), they will be killing and feeding on more prey. This results in the prey population declining. Death rate has now exceeded birth rate in the prey.
5. However, if the prey population is falling, this means food is less readily available to the predators. The predators may have to expend more energy to catch the increasingly scarce prey. The prey may be stronger (less weak) and so better at evading capture as they have less intraspecific competition for their own food sources (hence they are better nourished); they may have fewer diseases and parasites (as these don’t spread readily in a sparse population).
6. The predator population may now fall as the predators struggle to get enough food: they may reach breeding age later due to poor nutrition and fewer offspring may survive to breed themselves. If the predator population has exceeded carrying capacity, its numbers may also be declining due to increased disease or parasite transmission. Death rate of predators now exceeds birth rate.
7. As the predator population falls, there are fewer predators killing prey. Hence the prey population has the opportunity to increase again: the above sequence of events will restart and repeat. Both populations will oscillate over time, but the changes in the predator population always lag behind those in the prey population.
33
Why are predator-prey relationships rarely as simple as the model?
There are other biotic and abiotic factors to consider
34
What is conservation?
Conservation is the active management of a habitat/ecosystem (by humans)
with the aim of maintaining or increasing its biodiversity.
35
What is preservation?
Preservation is the prevention of any human activity in a pristine ecosystem,
in order to avoid its damage or modification.
36
What type of process is conservation and why?
A dynamic one, as it needs constant adaptation to changes within the ecosystem
37
What is reclamation?
Restoring ecosystems which have been damaged or destroyed
38
What does pristene mean?
By pristine, we mean that there has not already been any significant human impact
39
What are 3 examples of commonly preserved ecosystems?
1. Marine conservation zones 2. Nature reserves 3. Newly discovered caves
40
What things are maintained in conservation?
genetitc, habitat and species biodiversity
41
What are 3 classes of reasons for the importance of maintaining biodiversity?
1. Economic
2. Ethical
3. Social
42
What are 5 techniques used as part of conservation?
1. Managing land
2. Taking steps to encourage new habitats
3. Removing animals to captivity
4. Growing plants in cultivation
5. Reclamation
43
What is a technique humans can use to encourage new habitats?
Controlled habitats
44
Is anything removed from a preserved area?
No
45
What are 3 threats to biodiversity?
1. Habitat loss 2. Invasive species 3. Overexploitation
46
What are 3 reasons wild populations may be overexploited by humans?
1. For food 2. For sport 3. For commerce
47
What are 3 reasons habitats may be disrupted by humans?
1. Intensive agricultural practices 2. Increased pollution 3. Building
48
What is a sustainable resource?
Renewable resource that is being economically exploited in such a way that it will not diminish or run out.
49
What are 5 methods used for conservation?
1. National parks
2. Green belts (areas of green land)
3. SSSIs (Sites of Special Scientific Interest)
4. Legal protection
5. Ex Situ conservation
50
What is sustainable management of the environment necessary for?
Conservation of natural resources for future generations
51
What are the 5 aims of sustainability?
1. Preserve the environment
2. Ensure resources are available for future generations
3. Allow humans in all societies to live comfortably
4. Enable LEDCs to develop through exploiting their natural resources
5. Create even balance in consumption of resources between LEDCs (less economically developed countries) and MEDCs (more economically developed countries)
52
What technique is used to produce sustainable timber on a small scale?
rotational Coppicing
53
What is coppicing?
Cutting tree trunks near the ground, which allows new shoots to form from the cut stumps and mature, before these shoots too are cut.
54
What is a use of the shoots from coppicing?
Fencing
55
What type of coppicing is used in most managed woodlands?
Rotational coppicing
56
benefits of rotational coppicing
The timber from rotational coppicing is a sustainable resource: it will remain available into the future, since the rate of regeneration of the resource (at least) matches its rate of harvest;
There is an ongoing economic benefit to the landowner, who has a predictable yield of timber to sell each year: the timber from coppicing (called ‘small wood’ due to the relatively narrow diameter of the logs) is used for making fences, garden furniture, charcoal etc;
Biodiversity is increased due to there effectively being nine different habitats in the ecosystem, each with different light intensities and
different stages of tree (re)growth: different species of plants, insects and birds will thrive in the particular conditions present in each section.
The high biodiversity may attract visitors to the woodland (ecotourism): they may psychologically benefit from spending time there, and may provide economic opportunities for the landowner e.g. a pay‐and‐display carpark or a café.
57
describe rotational coppicing
1. The woodland is divided into (for example) nine sections of equal size;
2. In one section only, suitable trees (e.g. hazel, sweet chestnut) are cut down close to ground level, leaving a coppice stool or stump;
3. Over the next nine years, the stumps will grow new shoots from their remaining meristem tissue;
4. Each year, a different section of the woodland is coppiced, i.e. the scheme is rotational;
5. By the time all nine sections have been coppiced, the trees in the original section have regrown sufficiently that their timber can be harvested again.
58
What is the difference between coppicing and pollarding?
tree is cut much higher up the trunk, safely out of reach of deer.
59
What is an advantage of pollarding over coppicing?
Deer and other animals cannot eat the shoots
60
What are 3 disadvantages of large-scale timber production?
1. Habitats are destroyed 2. Soil minerals are reduced 3. Bare soil left is susceptible to erosion
61
What technique to companies use to do sustainable large-scale timber production?
Selective felling and replanting
62
What are 5 examples of techniques used to guarantee sustainable fishing?
1. fishing quotas
2. Use of nets with different mesh sizes
3. Seasonal restricitons - Allowing fishing only at certain times of the year
4. Introducing fish farming to reduce loss of wild species
5. Marine Conservation Zones
63
What 2 things are balanced in the Masai Mara nature reserve?
Need for conservation and needs of humans
64
What country is the Masai Mara nature reserve in?
Kenya
65
What type of ecosystem is the Masai Mara primarily?
Savannah
66
What divides the Masai Mara?
The Mara river
67
What plant which once dominated the Masai Mara has been largely cleared over the last 50 years?
Acacia bush
68
Why was the Acacia cleared so aggressively in the Masai Mara?
It provided a habitat for the tsetse fly, which causes sleeping sickness
69
What 4 things have reduced Acacia coverage in the Masai Mara?
1. Elephants
2. Cattle
3. controlled Fires
4. Efforts by the government
70
What have local tribes traditionally used the Masai Mara for?
Livestock grazing and cultivation
71
What traditional farming method did the local tribes in the Masai Mara?
Semi-nomadic farming - they move around depending on climate and prescence of tettse fly
72
What 2 things traditionally caused tribes to move in the Masai Mara?
1. Tsetse flies 2. Climate variation
73
What was an advantage of the Masai Mara tribes' traditional semi-nomadic farming?
Allowed vegetation to grow back from animal grazing
74
How is grazing now limited in the Masai Mara?
Limited to the edge of the national park as tribes are not allowed in
75
What are some disadvantages of the new grazing practices in the Masai Mara?
More trees removed for fuel, larger herds graze grasslands, risk of soil erosion increases with reduced vegetation
76
How has cultivation changed in the Masai Mara recently?
It has increased
77
What 2 negative things have happened as a result of increased cultivation in the Masai Mara?
1. Nutrients in soil used up 2. Reliance on fertiliser developed over time due to lack of soil nutrients
78
What provides most of the economic input of the Masai Mara?
Ecotourism
79
What is ecotourism?
Tourism directed towards natural environments, to support conservation and observe wildlife
80
What does ecotourism reduce?
The impact of tourism on natural habitats
81
What are the 3 key principles of ecotourism?
1. Ensure that tourism does not exploit the natural environment or local communities 2. Consult and engage with local communities on planned improvements 3. Ensure that infrastructure improvements benefit local people as well as visitors
82
Why can ecotourism have a negative impact on the environment?
Tourist movements such as repeated use of hiking trails, or use of mechanised transport, may contribute to soil erosion or other habitat changes
83
What species were protected by conservation and preservation efforts in the Masai Mara?
Black Rhinos
84
What caused people to be lured into Rhino poaching in the Masai Mara?
The large amounts of money on offer combined with their poverty
85
What caused a large decline in the Black Rhino population of the Masai Mara?
Illegal poaching
86
What are currently being undertaken in the Masai Mara?
Scientific research project
87
What are 4 examples of balancing the needs of humans and wildlife in the Masai Mara?
1. Elephants can threaten cultivation and eat crops so land can be fenced, but as this can affect migration it must be done in moderation 2. Legal hunting used to cull excess animals, but with constant monitoring of numbers 3. As livestock is threatened by migratory wildlife the needs of both must be managed 4. Expanding human population means more home and land for livestock needed, so must be managed as not to reduce wildlife density
88
What and where is the Terai region?
A rich agricultural region of Southern Nepal
89
Why are natural resources at risk of being overused in the Terai?
High population density and prevalence of agriculture
90
What are there large areas of in the Terai region?
Thick forests
91
What is the soil like in the Terai region?
Very fertile
92
Why have large areas of the Terai forests been cleared and what for?
Agriculture or to sell the timber, largely as a result of poverty and corruption
93
What is the Terai climate like?
Hot and humid in summer
94
How biodiverse is the Terai region?
Very biodiverse
95
What problem in the Terai region has been exacerbated by deforestation?
Flooding during the monsoon season
96
Why would the near complete loss of forest in the Terai be devastating for the local population as well as wildlife?
They rely on the forests for tourist income and timber for construction and fuel
97
What 2 examples of sustainability can be seen in the Terai region?
1. Sustainable forestry 2. Sustainable agriculture
98
What 2 groups have helped sustainable forestry in the Terai region?
1. Nepali government 2. Local worker cooperatives
99
What have been 6 successes of sustainable forestry in the Terai region?
1. Significant improvement in forest conservation 2. Improved soil and water management 3. Increase in retail price of forestry products 4. Securing biodiversity of forested areas 5. Sustainable wood fuel sources 6. Employment and income generation through forest protection
100
What have been 6 sustainable agriculture techniques used in the Terai region?
1. Growth of nitrogen fixing plants to improve soil fertility 2. Growing resistant crops 3. Improved irrigation 4. Promoting production of fruits and vegetables in lesser used mountains to lower intensification 5. Multiple cropping 6. Improved fertilisation techniques
101
What is a peat bog?
A region of wet, spongy ground that contains decomposing vegetation
102
What can undisturbed peatland act as?
A carbon sink
103
Why is preserving peat bogs important in fighting climate change?
Dried peat, when burned, releases carbon dioxide, and new peat bogs take thousands of years to form and become a carbon sink
104
What else is peat commercially extracted for apart from to be used as fuel?
For use in gardening
105
How do peat bogs form?
When plant material is inhibited from decomposing properly by acidic and anaerobic conditions
106
How are plants which thrive on peat bogs adapted?
To live in wet conditions with few nutrients
107
What 4 things will continued peat bog preservation contribute to?
1. Maintained biodiversity 2. Erosion control 3. Carbon storage 4. Flood management
108
What 3 activities have historically destroyed peat bogs?
1. Planting of forests 2. Peat extraction 3. Agricultural intensification
109
What 3 methods are used to preserve lowland UK peat bogs?
1. Ensuring peat and vegetation of bog surface is as undisturbed as possible, such as by using ditches to block off drainage 2. Removing seedling trees 3. Using controlled grazing
110
What currently threatens the remaining UK peat bogs?
Continuing intensive land usage
111
What are environmentally sensitive ecosystems?
Ones which are less resistant to change than others
112
What are 5 techniques used to protect environmentally sensitive ecosystems?
1. Limiting areas tourists can visit 2. Controlling livestock movement 3. Introducing anti-poaching measures 4. Replanting of forests and native plants 5. Limiting hunting through quotas and seasonal bans
113
Why are the Galapagos Islands of special interest?
They have never been connected to the mainland, so any plants or animals will have had to have travelled thousands of miles
114
What are most land animals on the Galapagos Islands?
Reptiles
115
How did reptiles arrive on the Galapagos Islands?
On floating rafts
116
What are the 3 distinct regions of the Galapagos?
1. Humid 2. Coastal 3. Arid
117
What caused damage to the ecosystem of the Galapagos Islands from the 19th century onward?
Whalers and their pet goats (which may have outcompeted the giant tortoises)
118
What 4 measures have been taken to protect the ecosystem of the Galapagos Islands?
1. Introduction of park rangers 2. Limiting human access to certain islands, or parts of islands 3. Controlling migration to and from islands 4. Strict controls over movement of introduced animals such as pigs
119
What 3 things did whalers do to damage the Galapagos Islands?
1. Cut down forests to render whale fat 2. Removed tens of thousands of giant tortoises 3. Allowed domestic pets to run wild
120
What is the climate like in Antarctica?
Very cold and nearly the whole spot is covered in ice
121
What do all vertebrates living in Antarctica rely on?
A layer of blubber to keep them warm
122
Do any plants grow in Antarctica?
Yes, but only in the small ice-free regions
123
What are 5 provisions of the 1961 Antarctic Treaty?
1. Scientific cooperation between nations 2. Protection of Antarctic environment 3. Conservation of plants and animals 4. Management of tourism 5. Designation & management of protected areas
124
What are 4 effects of humans on Antarctica?
1. Soil contamination 2. Planet-wide effects caused by global warming and the hole in the ozone layer 3. Pollution caused by discharge of waste into the sea 4. Hunting of whales, seals and fish has depleted their stocks
125
What was created in 1951 to protect the biodiversity of Snowdonia?
Snowdonia national park
126
What is an example of the needs of humans and animals being met in Snowdonia?
Large pumped storage hydroelectric power station being located inside a mountain to minimise effects on wildlife
127
What is an example of active management in the Lake District National Park?
Replanting native tree species
128
What is the purpose of the Lake District National Park Authority?
Conserving the region while allowing access for millions of tourists a year
129
What are the 3 key purposes of the Snowdonia National Park Authority?
1. Conserve and enhance natural beauty, wildlife and cultural heritage of area 2. Promote opportunities for understanding and enjoyment of special qualities of park 3. Enhance economic and social wellbeing of communities within park
