Populations Flashcards
Population
A group of interbreeding organisms of one species in a habitat
Community
All populations of different organisms living in a particular place at the same time
Ecological niche
Where an organism lives and what it does there including all biotic and abiotic factors
Habitat
The place where a community of organisms lives
What are the stages of mark - release - recapture?
Set traps for a few hours, catch animals
Mark the caught animals, record the numbers and release
Set traps again in the same places
See how many are recaptured
Mark - release - recapture calculation
Total no. in first sample x total no. of individuals in second sample
Over
No. of marked individuals recaptured
What assumptions are made for mark-release-recapture?
Few deaths or births
No migration of the population
Individuals released distribute evenly amongst the remaining population
Abiotic factors
pH
Temperature
Humility
Light
Biotic factors
Competition
Predation
Intraspecific competition
Between individuals of the same species
Determines the size of a populations
Interspecific competition
Between individuals of different species
Where two species occupy the same niche
Competing for space water and food
Factors affecting birth rate
Economic conditions - low capita, high birth rate
Birth control - contraception, abortion
Political factors- one child policy
Factors affecting death rate
Life expectancy at birth
Sanitation and safe drinking water
Healthcare improvements
War
Natural disasters
Stable population characteristics
Birth rate and death rate is balanced
No increase or decrease
Narrow base, even all the way up
Increasing population characteristics
High birth rate
Low life expectancy
Wide base and narrow apex of the pyramid
