Populations Flashcards
Define abiotic factor
Non-living conditions in a habitat
Define biotic factor
Living components of an ecosystem
Define limiting factor
A component which prevents the rate of a process getting any greater
Define carrying capacity
The maximum population size that an environment can support
Give 3 examples of limiting factors for population size
- disease
- build up of toxic by-products
- availability of water/food
What is stage 1 of the standard growth curve called?
Lag phase
What happens in the lag phase?
- occurs due to acclimatisation
- low reproduction rate
- death rate lower than birth rate
What is stage 2 of the standard growth curve called?
Exponential phase
What happens in the exponential phase?
- rate depends on intrinsic rate of increase
- population grows rapidly
What is stage 3 of the standard growth curve called?
Stationary phase
What occurs in the stationary phase?
- death rate=birth rate
- carrying capacity reached
- slight increases and decreases occur
Define density independent factors
Factors that have an effect on the whole population regardless of its size
Give 3 examples of density independent factors
- Light intensity
- Temperature
- Climate
Define density dependent factors
Factors whose effects on the size or growth of the population vary with the population density
Give an example of a density dependent factor
Availability of food/water
