Populations and Sustainability Flashcards
Phases of a population-growth curve
Phases of a population-growth curve:
1 - Slow growth -> small number of individuals present reproducing
2- Rapid growth = higher breeding individuals, br higher than dr
3 - Stable state = breeding rate and death rate the same as growth prevented by external constraints
Limiting factors in ecosystems
Limiting factors:
-Abiotic = non-living > temp, pH, light
-Biotic = living -> predators, prey, disease, competition
What is carrying capacity?
Carrying capacity = maximum population size an environment can hold
-Population size affected by migration
What are density independant factors?
Density independant factors = factors that have an aeffect n the whole population regardless of its size
Types of competition in ecosystems
-Interspecific = competition between different species
-intraspecific = compeition between individuals of the same species
Interspecific compeition
Interspecific competition:
-2 or more different species compete for same resources
-Results in total resource reduction
-Less adapted species will be outcompeted
-Eg red and grey squirrels compete for food but grey is better adapted due to wider range of food
What is the competitive exclusion principle
Competitive exclusion principle = if conditions remain the same - less adapted species decrease
Intraspecific competition stages
Intraspecific competition:
-Resource plentiful
-Resources limits as population increases
-Less population -> less competition -> more survive
Stages of a predator-prey relationship (graph)
Stages of a predator-prey relationship (graph);
-Increased prey, food for predators and they increase
-Decline in prey
-Decline no longer supports predator population - intraspecific competition - predators decrease
-Prey increases as a result
-Cycle repeats
What is conservation?
-Conservation = maintenance of biodiversity through human action or management
-Leads to sustainable management
-Reclamation = restores damaged exosystems ie controlled fires
What is preservation?
Preservation = protection of an area by restricting or banning human interference
-For sensitive and vulnerable areas with resources
What is the importance of conservation?
Importance of conservation:
-Economic (to provide resources for surivval and for an income
-Social (enjoyment and exercise)
-Ethical (right to existent and role important within ecosystem)
What are the aims of sustainability?
Aims of sustainability:
-Preserve the environment
-Ensure resources are available for future generationsly
-Allow humans in all societies to live comfortably
What is coppicing?
-Coppicing = Produces sustainable timber on a small scale where tree trunk cut close to the ground
-new shoots from the cut surface and mature
-Rotational coppicing - woodland divided in sections and trees cut into until all has been coppiced then original coppiced trees cut as theyve grown back by then etc
-Maintains biodiversity as trees never grow enough to block light, and so sucession cannot occur and more sepcies survive
How can timber companies sustainably produce timber?
Sustainable timber production:
-Practise selective cutting, removing only larger trees
-Replace trees through replanting rather than waiting for natural regeneration
-Plant trees optimal distance apart to reduce compeition
-Manage pathogens to maximise yield
Sustainable fishing methods
Sustainable fishing methods:
-Fishing quotas
-Nets with different mesh sizes
-Allowing commercial and recrational fishing only at certain times a year
Key principles of ecotourism
Key principles of ecotourism:
-Ensures tourism does not exploit natural environment
-Consults and engage with local communities on planned developments
-Ensures infrastructure improvements benefit local people
How to promote sustainable agriculture?
Promoting sustainable agrictulture:
-Multiple cropping where multiple crops are grown on piece of land
-Growth of nitrogen-fixing crops to enhance soil fertility
-Improve fertilisation techniques to enhance yield
-Genetic engineering to grow crops viable for multiple conditions
Outline sucession.
→ Primary sucession → Progressive colonisation of bare rock or other barren terrain by living organisms:
1 = Pioneer species colonate the area, changing the abiotic factors to be less hostile for other species to surivve
2 = Different species present at each stage, changing the environment so it becomes suitable for other species with different adaptations
3 = Climax community = stable state = high biodiversity
→ Secondary sucession → recolonisation of an area after an earlier community has been removed or destroyed
What are the advantages and disadvantages of in-situ conservation?
→ Advantages → Conserves species without removal, ecosystem integrity maintains as species play role in ecosystem functioning, cheaper than ex situ
→ Disadvantages → habit may be too fragmented for sustainability, genetic diversity may be too low already, reserves may be damaged by ecotourism
What are the advantages and disdvantages of ex-situ conservation?
→ Advantages → Protects organisms from predation and poaching, helps attract funding and awareness
→ Disadvantages → limited genetic diversity, difficult to provide suitable environment, organisms struggle when re-introduced into the wild
How to conserve lowland bogs?
-Ensure that the peat and vegetation is undisturbed and wet, such as blocking surrounding ditches for a period of time to raise water table to bog surface
-Removal of surrounding seedling trees due to its high water requirement
-Controlled grazing to maintain its biodiversity
