Populations And Sustainability Flashcards
What is a limiting factor in terms of population growth?
Environmental resource or constraint that limits population growth
Give an example of a limiting factor of population growth
Food availability
What are the 3 main stages of a population growth curve? Explain them
Phase 1. Slow growth
Small group of individuals reproducing but birthrate > death rate so population grows
Phase 2. Rapid growth
Breeding individuals increases and no constraints act to limit population increase
Phase 3. Stable state
Further growth is prevented by external constraints, population fluctuates but is relatively stable birth rate = death rate
What is phase 3 of the population growth curve known as?
Carrying capacity of a population
List 4 abiotic limiting factors affecting population growth
- Light
- PH
- Water availability/ oxygen availability
- Humidity
List 3 biotic limiting factors affecting population growth
- Predators
- Disease
- Competition
What is the definition of carrying capacity?
The maximum population size that an environment can support
Define Immigration
Immigration is the movement of individual organisms INTO a particular area that INCREASES population size
What is an example of a organism that Immigrate
Christmas islands red crabs move from forest to shore to reproduce
Define Emigration
The movement of individual organisms AWAY from a particular area DECREASES population size
Give an example of Emigration
The Norway lemming emigrates away from areas of high population density of poor habitat
What is a density independent factor ?
Factors that have an effects on the whole population regardless of its size
What are the 4 density independent factors?
Earthquakes, fires, volcanic eruptions and storms
Is competition abiotic or biotic limiting factor?
BIOTIC - it is an interaction of living organisms
What is interspecific competition?
Competition between different species
What is intraspecific competition?
Competition between members of the same species
When does interspecific competition occur?
Interspecific competition occurs when two of more different species of organism compete for the same resource
What is the competitive exclusion principle?
When in interspecific competition, the species that use the resource more effectively will eliminate the other species
Give an example of interspecific competition
Red and grey squirrels - grey squirrels have a larger range of diet
When does intraspecific competition occur?
When members of the same species are competing for the same resource
What does the availability of resources determine in intraspecific competition?
The size of the population
What does intraspecific competition result in for species?
Fluctuations in the number of organisms in the population
Describe the 3 stages of the intraspecific competition graph
Stage 1 - increase
Resource is plentiful and all organism have enough to serve and reproduce
Stage 2 - decrease
As the population has decreased there are more individuals to share the resource so it is limited and not enough for everyone to survive
Stage 3 - increase
Less competition in smaller population so more organism survive and reproduce (cycle)
What time of competition is predation?
Interspecific as it operates between two different species
Describe and explain the 4 stages of predator-prey relationship graph
Stage 1 - increase in prey population provide more food for predators (after a short delay) predator population increase
Stage 2 - increased predator population causes a fall in prey population so death > birth rate of prey
Stage 3 - reduced prey population no longer supports increased predator population so decrease in predator population
Stage 4 - reduced predator numbers result in less prey being killed so they reproduce and survive
Cycle repeats again
Is the predator prey graph representative of in the wild?
NO other factors such as food availability for prey, other predators or seasonal changes will also have an impact on
What is the definition of conservation?
Maintenance of biodiversity through human action or management
Conservation involves the management of ecosystems so natural resources can be used without running out, what is this called?
Sustainable development
Give an example of conservation
The forest stewardship council ensures that their tumbler supply is sustainable
What is reclamation conservation?
Th process f restoring ecosystems that have been damaged or destroyed
What is the definition of preservation?
The protection of an area by restriction of banning human interference so an ecosystem is kept in its original state
What sites are often preservation sites? And what isn’t allowed here
Archaeologiclly paleontological and ecological sites
No visitation is allowed
What are examples of preserved habitats?
Nature reserves and marine conservation
What is the economic importance of conservation? Give an example
To continue providing resources that humans need to survive
E.g rainforest supply medicinal drugs
What is the social importance of conservation? Give an example
Many people enjoy the natural beauty of wild ecosystems
E.g birdwatching, cycling, walking
What is the ethical importance of conservation?
All organisms have a right to to exist as well as play a role in their ecosystem
We also have a moral responsibility for future generations
What has occurred due to exploitation of environmental resources due to human demand?
Destruction of ecosystem, reduction in biodiversity and depletion of resources
What is a sustainable resource?
Renewable resource that is being economically exploited in such a way that it will not diminish or run out of
What are the 5 aims of sustainability?
- Preserve environment
- Ensure resources are available for future generations
- Allow humans in all societies to live comfortably
- Enable LICs to develop through natural resources
- Creates a balance in consumption of resources between HICs and LICs
What technique is used for sustainable small scale timber production?
Coppicing is used