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