Chap 24 - Populations & Sustainability Flashcards
Define abiotic factor
non-living components of an ecosystem (eg. light intensity, temperature, pH, O2 availability)
Define biotic factors
living components of an ecosystem (eg. disease, competition, predation)
Define limiting factor
factor that limits the rate of a process - environmental resource/constraint that limits population growth
Define carrying capacity
the maximum population size that an environment can support
Give 3 examples of limiting factors
competition, disease, build-up of toxic by-products of metabolism
Define migration
the movement of members of a species to a different environment
Define emigration
movement of individual organisms AWAY from a particular area
Define immigration
movement of organisms INTO a particular area
Define density independent factors
factors that have an effect on the whole population regardless of its size
State 3 examples of density independent factors
earthquakes, volcanic eruptions, fires
Define intraspecific competition
competition within members of the same species
Define interspecific competition
competition between organisms of different species
Give 4 examples of what organisms might compete for
food, water, space, light (plants)
Describe competition exclusion
where two species competing for limited resources, the one that uses the resource more effectively will ultimately eliminate the other
Explain the competition exclusion principle
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
Explain the fluctuations caused by intraspecific competition
- when resources are plentiful, all organisms have enough to survive and reproduce = increase in population size
- there are more individuals sharing resources, they become limited and not enough for all organisms to survive.= decrease in population size
- less competition means less organisms competing for same resources, more organisms survive and reproduce = population increase
Define predation
where an organism kills and eats another organism
Describe an explain the general pattern shown in predator-prey cycles
- 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
Define conservation
maintenance of biodiversity through human action or management
Define preservation
protection of an area by restricting or banning human interference - ecosystem is kept in its original state
Give 3 examples of conservation
- controlled grazing of fens
- controlled burning of forest (halts succession and increases biodiversity)
- zoos
Give 3 examples of preservations
- banning human development in certain areas
- ban visitation in newly discovered areas
- marine conservation zones
Define reclamation
process of restoring ecosystems previously damaged/destroyed
Give social arguments for the importance of conservation
- people using natural beauty of wild ecosystems for activities (eg. bird-watching, cycling, climbing)
Give economic arguments for the importance of conservation
provides resources that humans need to survive to provide an income eg. medicinal drugs, food, clothes that can be traded
Give ethical arguments for the importance of conservation
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
What is a sustainable resource
renewable resource that is being economically exploited in a way that they won’t diminish or run out
What are 5 aims of sustainability
- 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
What are examples of sustainability
reusing and recycling existing resources
What is coppicing?
cutting a tree trunk close to the ground creating multiple smaller trunks from one
What is pollarding
similar to coppicing but the trunks are cut higher to prevent deer and other animals from eating new shoots
What are examples of large scale timber production
- selective cutting (only large trees)
- replanting
- distance trees
- manage pests and pathogens
- leave areas for indigenous people to use
What are negative implications of large scale timber production
- soil vulnerable to erosion
- soil minerals reduced as washed away
- habitats destroyed
Explain fishing
- as global pop. increases, demand for food increases
- fish is valuable source of protein
- overfishing has impacted fish pop. sizes
What are fishing quotas
limit the number of fish caught by species
- if they are exceeded = fined
Why do fishermen use large mesh nets
to allow immature fish to escape so only mature fish are caught - allows them to reproduce and mature healthily
Why are fishing months limited
to protect breeding seasons. eg. red snapper can only be caught in the gulf of mexico between May and June
What is fish farming
allows high supply of fish without affecting wild species population sizes
Where is the Terai region?
Southern Nepal
How wide is the Terai region
25-30km
How are the Terai lowlands defined?
by a belt of well watered floodplains
Where does the Terai region stretch from?
from the Indian border in the south to the slopes of the Bhabhar and Siwalik mountain regions in the north
The land of the Terai region is ___, and is the ______ of the country.
- fertile
- main agricultural region
What are people engaged in?
farming, a range of trades, industries and services
Why are natural resources at risk of being overused?
due to high population density
Describe the atmosphere of the region
- 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
What is the Terai region important for?
- millions of people depend on the forests for their livelihood
- important source of national income
What has poverty and corruption done to the area?
- cleared larges areas of forest for agriculture/sell timber
What has the removal of large sections of forests caused
exacerbated effects of monsoon flooding - caused severe disruption to communities downstream
What will happen is deforestation is left unchecked
there will only be small pockets left of forest - devastating for wildlife and the local population who rely on the forests for income
State how the environment is being changed and describe the effects of this?
- 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
What are the aims of sustainable forest management?
- provide livelihood for local people
- ensure conservation of the forest
- provide Nepali state with considerable income for development
How is the sustainable forest management being achieved?
- national legislation
- development of local community forestry groups
What do local forestry groups do?
- develop own operational plans
- set harvesting rules
- set rates and prices for products
- determine how surplus income is distributed or spent
What have local forestry groups done through the creation of cooperative networks?
- allows small forestry businesses can work effectively together eg. to gain Forestry Stewardship Council (FSC) certification
What is the FSC?
an international standard which rewards sustainable forestry
Name 6 successes for the community forestry groups?
- 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
Why does the Terai region require a range of management strategies?
- to prevent damage of the ecosystem
What management strategies are in place in the Terai region?
- 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
What is a peat bog?
regions of spongy wet ground that contain decomposing vegetation
What is undisputed peatland considered
a carbon sink
Why is peatland considered a carbon sink
when it is dried and use as fuel, co2 is released into the atmosphere
Why is it important to preserve peat bogs
they take thousands of years to form - preservation prevents further climate change
What is peat used for?
as well as fuel - it is important for farmers and gardeners - it can improve soil structure and increase acidity
Why does peat change the structure of the soil?
peat retains water when soil is dry - prevents excess water killing roots when soil is wet
What is a major threat to farmers and gardeners ecosystems?
commercial peat extraction
When does peat form
when plant material is inhibited from fully decaying by acidic and anarobic conditions - usually in wet and boggy conditions
What is peat composed of?
mainly wetland vegetation (eg. mosses, sedges, shrubs)
What are peatland plants adapted for
to grow and thrive in wet conditions with few nurtrients
Why are peatlands ideal for many species
- they support a wide range of insects - some act as a food source
- lack of predators and human disturbance makes it ideal
What is an example of a peatland ecosystem
lowland raised bogs - rare and threatened habitat
In the UK, the area of undisturbed lowland raised bog has dropped by over ____ in last 100 years
90%
What has the decline been caused by?
peat extraction, afforestation, agricultural intensification, including land drainage
What is afforestation
the establishment of a forest or stand of trees in an area where there was previously no forest
Why is it important to conserve peatlands
to maintain biodiversity, contribute to flood manage, carbon storage and erosion control downstream
How can lowland bogs be conserved?
- 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
___ of the UK is classified as peat bog
10%
Around ___ of these areas are in poor condition
80%
What organisations work to preserve peat bogs?
- the wildlife strusts
- natural england
- the royal society for the protection of birds (RSBP)
Describe the ecosystem of the Masai Mara (1 mark)
Savannah / open grassland - open grassland with occasional shrub and trees (1)
State 2 ways in which humans use the lands of the Masai Mara (1 mark)
tourism / ecotourism and farming / grazing (1)
Explain how and why local Masai tribes have changed their style of farming in recent years (4 marks)
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)
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)
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)
Describe the ecosystem of the Terai region of Nepal (2 marks)
mixture of agricultural land, with dense forest regions (1); region is hot and humid in summer months / subject to monsoons (in rainy season) (1)
State 2 ways humans use the Terai region of Nepal (1 mark)
any two from: growing crops / agriculture (1); forestry / felling timber for building resources / burning as fuel (1); tourism (1)
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)
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)
Define environmentally sensitive ecosystems
ecosystems that are less resistant to changes than others
What are the management techniques used in environmentally sensitive ecosystems
- 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
What are The Galapagos?
an archipelago of volcanic islands that sie up from the best of the Pacific Ocean 1000km west of Ecuador
Why are The Galapagos of special interest
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
What types of animals live on the islands
- 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
How did the animals get to the islands?
by being washed away from mainland river banks/ floating on rafts of vegetation
What are ectotherms and why are marina iguanas an example of this
- 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
What regions are present on The Galapagos
- 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
What measures have been put in place to protect living and non-living parts of the ecosystem
- 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
