24.1 Populations And Sustainability

Question 1

What are the 3 main stages of the Population curve?

Answer 1

Phase 1 - slow growth phase

Phase 2 - rapid growth phase

Phase 3 - stable state

Question 2

Explain phase 1 of population growth curve?

Answer 2

Number of individuals initially present reproduce increasing the total population. As the birth rate is higher than the death rate, the population increases in size.

Question 3

Explain phase 2 of the population growth curve?

Answer 3

As the number of breeding individuals increases, the total population multiplied exponentially. No constraints limit the population explosion.

Question 4

Explain phase 3 of the population growth curve?

Answer 4

Further population growth is inhibited by external constraints. During this time the population size fluctuates but its overall size remains relatively stable. Birth rates and death rates are approximately equal. Slight increases and decreases can be accounted for by fluctuations in limiting factors such as the presence of predators.

Question 5

Examples of limiting factors to population growth?

Answer 5

Competition between organisms for resources.

Build up of toxic waste by-products of metabolism

Disease.

Question 6

What is the carrying capacity of an ecosystem?

Answer 6

Maximum population size that an environment can support

Question 7

How does migration impact population size?

Answer 7

Immigration - movement of individual organisms that increases population size. Eg Christmas Island crabs migrate from forest to coast to reproduce increasing the coastal population size.

Emigration - movement of individual organisms away from an area, decreases population size. Eg the Norway Lemming emigrates away from high population density areas and poor habitat.

Question 8

What are density independent factors?

Answer 8

Factors that have an effect in the whole population regardless of size. Examples include earthquakes, fires, volcanic eruptions and storms. In some instances entire populations can be wiped out.

Question 9

What factors affect human birth rate?

Answer 9

Natural limiting factors
Economic conditions
Cultural and religious backgrounds
Social pressures

Question 10

What can affect the death rate una human population?

Answer 10

The age profile
Quality of medical care
Food and water availability
Quality of food and water
Presence of disease
Effects of natural disaster / war

Question 11

What is interspecific competition?

Answer 11

Competition between different species

Question 12

What is intraspecific competition?

Answer 12

Competition between members of the same species.

Question 13

Explain the impact of interspecific competition?

Answer 13

Leads to a reduction in resources. Eg both compete for same food source = less of the food source = less energy for growth and reproduction = smaller populations.

Outcompetition can occur if one species is better adapted than the other. If this condition continues, the less adapted population will decrease in size until it no longer exists = competitive exclusion principle.

Question 14

Name an example of interspecific competition in the UK?

Answer 14

Red and Grey Squirrels,

Red are native to UK but grey arrived from USA, due to interspecific competition the population of red squirrels declined hugely.

Grey squirrel is better adapted as it can eat a wider range of foods than the red squirrel and it is larger as it can store more red fat.

This leads to the competitive exclusion principle.

Question 15

Explain the impacts of intraspecific competition over time?

Answer 15

When a resource is plentiful in a habitat, all organisms have enough of the resource to survive and reproduce, increasing population size.

As a result of increased population, more individuals share the food and resources / space. These resources are now limited, not enough is available for all organisms to survive therefore the population size will decrease.

Less competition exists as the smaller population means that less organisms are competing for the same resources. More organisms survive and reproduce leading to population growth.

This repeats continuously.

Question 16

Explain the predator prey relationships graph?

Answer 16

Stage one - increase in prey provides more food for predators so more can survive and reproduce, increasing the predator population.

Stage Two - increases predator population eats more prey organisms leading to decline in prey population. Death rate of prey population is greater than birth rate.

Stage Three - reduced prey population can no longer support the large predator population so intraspecific competition for food increases resulting in a decrease in predator population.

Stage Four - reduced predator numbers result in less prey being killed and more prey survive and reproduce, increasing the prey population - the cycle begins again.

Question 17

What is conservation?

What methods are there?

Examples?

Answer 17

The maintenance of biodiversity through human action or management. Includes maintaining biodiversity between species, maintaining genetic diversity within a species and the maintenance of habitats.

Includes sustainable development eg Forest Stewardship Council ensures forests are managed to provide a sustainable source of timber.

Also involves reclamation. Which is restoring ecosystems that have been damaged or destroyed and includes techniques such as controlled burning of areas of forest

Question 18

What is preservation?

Examples

Good / Bad?

Answer 18

Protection of an area by restricting or banning human interference so that the ecosystem is kept in its original state. Commonly used when preserving ecology, or archaeological sensitive resources etc.

Visitation is not allowed to preservation sites.

Newly discovered caves contain sensitive formations, walking from one cave to another can cause irreparable damage so preservation is required to prevent this.
No enjoyment of the rare landforms as no entry is permitted.

Question 19

What is the importance of conservation?

Answer 19

Economic - to provide resources that humans need to survive and to provide an income. Eg rainforests provide medicinal drugs, clothes and food that can be traded. Others used for timber and paper etc

Social - people enjoy visiting these places and the natural beauty that surrounds them, beneficial to health and relaxation and exercise. Eg bird watching, climbing, walking and cycling.

Ethical - all organisms have the right to exist and most play important roles to their ecosystem. Many believe that we should not interfere with which species should survive and which we can live without. Moral responsibility

Question 20

What is a sustainable resource?

Answer 20

A renewable resource that is being economically exploited in such a way that it will not diminish or run out.

Question 21

What are the aims of sustainability?

Answer 21

Preserve the environment
Ensure resources are available for future generations
Allow humans to live comfortably
Enables LEDCs to develop through exploiting their natural resources
Create a more even balance in the consumption of these resources between MEDCs and LEDCs

Question 22

What else should happen alongside sustainable use of resources?

Answer 22

Existing resources should be used up more efficiently, this helps to prevent finite resources from being used up so quickly eg, recycling can be used.

As technology improves alternatives may be developed that could ease the strain in current finite resources. However these new resources can take many years to develop.

Question 23

What is sustainable timber production?

Answer 23

Sustainable management of forests is possible it allows for the maintenance of forests biodiversity, while sustaining both our supply of wood to meet demands and the economic viability of timber production. The techniques depend on scale of timber production.

Question 24

What technique is used for small scale timber production?

Where does this happen?

How does rotational coppicing maintain biodiversity?

Answer 24

Coppicing is often used. This is a technique where a tree trunk is cut close to the ground. New shoots form the cut surface and mature

In most managed woodlands rotational coppicing takes place, woodland is divided into sections and trees are only cut in a particular section until all have been coppiced.

The trees never grow enough the block out the light. Hence; succession cannot occur and so more species can survive. An alternative technique to coppicing which may be used is pollarding. Similar to coppicing but the trunk is cut higher up so deer and other animals cannot eat the shoots as they appear.

Question 25

What do timber companies do to ensure large scale timber production?

Answer 25

Practise selective cutting, which involves removing only the largest trees.

Replace trees through replanting rather than waiting for natural regeneration. This also helps to ensure that the biodiversity and mineral and water cycles are maintained.

Plant trees an optimal distance apart to reduce competition. This results in higher yields as more wood is produced per tree.

Manage pests and pathogens to maximise yields

Ensure that areas of forest remain for indigenous people.

Question 26

What are the disadvantages to this timber production?

Answer 26

Habitats are destroyed
Soil minerals reduced
Bare soil that is left is susceptible to erosion.

Trees are important to binding soil together, removing water from soil, maintaining nutrient levels through their role in the carbon and nitrogen cycles.

Question 27

How are the protocols of sustainable fishing determined?

Answer 27

Through international agreements about the number of fish that can be caught.

Also the species of fish that have to be releases of caught.

These are in place to make sure that the population does not run below levels so reproduction can no longer occur.

Question 28

What other techniques of sustainable fishing are there?

Answer 28

Use of nets with different mesh sizes, nets with larger holes means that small unwanted fish can escape, immature fish remain allowing breeding to continue.

Only allowing commercial and recreational fishing at certain times of the year to allow breeding levels to bring the number of fish up to a sustainable level

Introduction of fish farming to maintain the supply of protein food whilst preventing the loss of wild species.

Question 29

How has farming changed in the Masai Mara?

Answer 29

Traditionally, grazing occurred all across the available land using semi-nomadic farming methods, tribes would move dependent on climate and presence of tsetse flies.
This allowed vegetation in other areas to recover as the tribe would move around.
Grazing is now limited to the outer edges of the nature reserve and local tribes are prohibited from entering the park. Populations growth in the margin and larger herds now graze the grassland leading to more soil erosion. Also more trees removed for fuel.

Question 30

How has cultivation changed in the Masai Mara?

Answer 30

Cultivation around the region of the MM has increased. Grasslands converted into croplands natural vegetation has been removed and nutrients in the soil are used up. Overtime this can lead to a reliance on fertilisers for effective crop growth.

Question 31

What is ecotourism?

Answer 31

Ecotourism is tourism directed towards natural environments to support conservation and observe wildlife. A type of sustainable development.

Question 32

What are the key principles of ecotourism?

Answer 32

Ensure that tourism does not exploit the natural environment or local communities.

Consult and engage with local communities on planned developments.

Ensure that infrastructure improvements benefit local people as well as visitors.

Question 33

Negatives of ecotourism?

Answer 33

Tourist movements can have negative impacts on the environment.
Repeated use of hiking trails or using mechanised transport can lead to soil erosion and other habitat changes.

Question 34

How were black rhinos protected as a part of conservation in the Masai Mara?

Answer 34

Employment of reserve rangers

Provision of communications equipment

Vehicles provided

These measures have deterred poachers from entering the reserve

Question 35

Name some examples of acientífico research projects that have taken place in the Masai Mara?

Answer 35

Michigan State Uni - studying the behaviour and physiology of the predator spotted hyena

Subalusky and Dutton - completing a flow assessment for the Mara River Basin. Air was to identify the river flows needed to provide for human needs and to sustain the ecosystem.

Mara Predator Project - catalogues and monitors lion populations throughout the region, identified population trends and responses to changes in land management, livestock, tourism and human settlements

Mara-Meru Cheetah Project - aims to monitor the cheetah population and evaluate the impact of human activity on cheetah behaviour and survival.

Question 36

Describe some balanced that must be maintained by the human and animal populations?

Answer 36

Elephants threaten cultivation. Large elephant populations are usually responsible for crop trampling and damage to homesteads. Other grazing animals may also eat the crops. To prevent this land may be fenced but this negatively impacts natural mitigation.

Legal hunting is used to kill excess animals, this successfully managed population numbers and brings in money for conservation work. However, numbers require constant management.

Livestock face threats from migratory wildlife. Annual wildebeest migration, wildebeest outcompete the cattle for grass, diseases may be introduced to domesticated animal populations.

Human population expands more as homes are required as well as land for cattle and agricultural. Wildlife populations decrease dramatically as the density of the built environment rises.

Question 37

Describe the ecosystem of the Terai region?

Answer 37

Fertile land
Hot and humid in summer months
Extreme biodiversity, there are subtropical plants as well as large areas of thick forests.
Millions depend on the forests for their livelihoods.
Important source of national income.

Poverty and corruption has lead to large scale clearing of forests for agriculture and to sell timber.

Deforestation has also caused bad flooding in monsoon seasons

Question 38

How is the Terai region sustainably managed?

What do local forestry groups do?

Answer 38

Supportive national legislation

Development of local forestry groups

These groups set their own operational plans, harvesting rules, set rates and prices for products and determine how surplus income is distributed.

Question 39

Name some examples of success in community forestry groups?

Answer 39

Significant improvement in the conservation of forested regions, in terms of increased area and improved density.

Improved soil and water management across the region.

An increase in retail price of forestry products and so a greater economic input to the region.

Employment and income generation through forest protection and production of non timber forests.

Sustainable wood fuel sources which contribute 3/4 of local household energy needs.

Securing the biodiversity of forested areas.

Question 40

Name some management strategies for sustainable land use in the Terai region?

Answer 40

Promoting the production of fruits and vegetables in the hills and mountain regions to avoid pressure on Terai

Improving irrigation facilities to enhance crop production

Multiple cropping, where more than one crop is grown on a piece of land each growing season.

The growth of nitrogen fixing crops such as pulses and legumes to enhance the fertility of the soil.

Growing crop varieties resistant to various soil, climatic and biotic challenges through the use of biotechnology and genetic engineering.

Improving fertilisation techniques to enhance crop yields eg using manure to improve nutrient content of soil.

Question 41

What is a peat bog?

Why is it useful?

Answer 41

A region of wet spongy ground that contains decomposing vegetation. Undisturbed peatland is a carbon ‘sink’ because it stored carbon dioxide.

Once dried peat can be used as a fuel, as well as releasing thermal energy, burning peat releases contain dioxide into the atmosphere and peat bogs take thousands of years to form.

Question 42

What do farmers use peat for?

Answer 42

Farmers and gardeners mix it with soil to improve soil structure and to increase acidity. Peat has favourable moisture retaining properties when soil is dry and prevents excess water killing roots when soil is wet.

Question 43

Where does peat form and what plants / animals live on a peatland ecosystem?

Answer 43

Peat forms when plant material is inhibited from fully decaying by acidic and anaerobic conditions. The is normally occurs in wet or boggy areas and peat is mainly composed of wetland vegetation including mosses, sedges and shrubs.

Sphagnum mosses, bog cotton or cottonsedge, and heathers typically live there and grow and thrive in the wet conditions with very few nutrients.

Bogs also support insects such as butterflies, moths, dragonflies and damsel flies. Lack of predators and human disturbance makes the ecosystem ideal for some bird nesting.

Abundance of wildlife provides food for many species. Ideal hunting ground for large birds of prey.

Question 44

Why is the loss of peat bogs so significant?

Answer 44

The area of relatively undisturbed lowland peat bogs is estimated to ha e dimished by over 90% from around 950km2 to around 60km2 in the last 100 years.

The maintenance of peat bogs contributes to flood management, erosion control downstream, and most importantly carbon storage.

Greatest decline caused by afforestation, peat extraction, and agricultural intensification, including land drainage.

Question 45

What steps are taken to conserve areas of lowland bogs?

Answer 45

Ensuring the peat and vegetation of the bog surface is as undisturbed and as wet as possible. Most bogs are surrounded by ditches to allow water to run off preventing flooding of nearby land.

Removal of seedling trees from the area. Trees have high water requirement due to transpiration. Therefore any tree seedling that has the potential to remove water from an area of peatland should be removed to maintain water levels in the area.

Using controlled grazing to maintain the biodiversity of peatland. Grazing ensures a diverse wetland surface in terms of structure and species composition. This in turn provides a wide range of habitats for many rare insect species.

Question 46

What are the general sustainable management techniques in sensitive areas?

Answer 46

Lim tiring the areas that tourists can visit

Controlling the movement of livestock

Introducing anti poaching measures

Replanting forests and native plants

Limiting hunting through quotas and seasonal bans

Question 47

What animals are present in the Galápagos Islands?

Answer 47

Majority mammals, arrived on the island after being washed away from mainland river banks and on floating rafts of vegetation.
Species that are unique to the island include;
- Galapagos giant tortoise grows to over 150cm
-flightless cormorant, reduced wings better for fishing underwater
- Marine Iguana, ability to swim causes by a mutation, an ectotherms than basks in the heat to raise the body temp to 36 degrees before swimming in to cold sea where they forage for food.

Question 48

3 regions ok the larger Galápagos Islands and what plant species are present?

Answer 48

The coastal zone - contains salt tolerant species such as mangrove and saltbush

The arid zone - contains drought tolerant species such as cacti and the carob tree

The humid zone - contains dense cloud forest which support populations of mosses and liverworts.

Question 49

How are the Galápagos Islands protected?

Answer 49

Introduction of park rangers across the islands

Limiting human access to particular islands or specific parts of islands

Controlling migration to and from the island

Strict controls over movement of introduced animals such as pigs (presence noted by Darwin)

Question 50

Animals present in Antarctica?

Answer 50

All endothermic animals rely on thick layers of blubber to insulate them from the cold eg Whales, penguins and seals.

• Wendell Seal can have blubber up to 10cm thick
• Emperor penguin only warm blooded animal that remains on the Antarctic continent during winter
• few invertebrates live there all year, smallest is the wingless midge and it has a body size of around 5mm.

Question 51

What plants can grow in Antarctica?

Answer 51

Plants can only grow in ice free regions (2% continent). Lichens and moss grow in any favourable niche such as sand soil, rock and on the weathered bones and feathers of dead animals. Algae can grow in many sheltered areas.

Question 52

Impact of human activities in Antarctica?

Answer 52

Global warming has lead to melting and part of the ice sheets breaking up, and also ozone depletion caused by human activities

Hunting of whales and seals and fishing of some Antarctic species has depleted stocks of these organisms.

Soil contamination, particularly around scientific research stations.

Discharging of waste into the sea

Question 53

Name some provisions of the Antarctic Treaty?

Answer 53

Scientific Cooperation between nations

Protection of the Antarctic environment

Conservation of plants and animals

Designation and management of protected areas

Management of tourism.

Question 54

Animals present in Snowdonia National Park?

Answer 54

Coast and estuary birds such as choughs, cormorants and oystercatchers.

Forest birds such as pied flycatchers, redstart and wood warblers.

Moorland and mountain birds such as ospreys, buzzards and sparrow hawks.

Also over 40 species of land mammals present including badgers, voles, deer and hedgehogs

Question 55

Plants present in Snowdonia?

Answer 55

Snowdon Lily and other arctic alpine plants that have evolved to cope with extreme conditions

Oak woodlands, alder and wych elm trees.

Question 56

Control of human activities in Snowdonia?

Answer 56

Park Authority to help to ;

• conserve and enhance the natural beauty; wildlife, and cultural heritage of the area
• promote opportunities for the understanding and enjoyment of special qualities of the park
• enhance economic and social well being of communities within the Park.

Dinorwig power station provides national grid with power using hydroelectric power, to preserve the beauty of the area, the power station was built in the cave to minimise the impact on the environment whilst meeting human demand for energy.

Question 57

Animals present in the Lake District?

Answer 57

Wide range due to varied landscapes.
Water voles, natter jack toads, and a number of species of bat, red deer and birds of prey such as golden eagle and ospreys.

Red squirrels and vendace are endangered species.

Question 58

Plants present in the Lake District?

Answer 58

Diverse range of arctic / alpine plants including purple saxifrage and alpine cinquefoil.

Specialised trees have adapted to harsh habitats including the dwarf juniper and dwarf willow.

Lower regions are home to the Sundew, one of the UKs few carnivorous plants. Insects are trapped within its leaves by a sticky mucilage (which glistens like morning dew) and enzymes are then secreted to digest the insect releasing its nutrients for the plant.

Question 59

How are human activities managed in the Lake District?

Answer 59

Active management of countryside eg through replanting native tree species. And sustainable exploitation management systems