Populations Flashcards
Define Population
All the organisms of one species in a habitat
Define Habitat
A location where an organism lives in the ecosystem
Define Community
All of the populations of different species in a habitat
Define Niche
The role of a species within it’s habitat
Define Abundance
The number of individuals of one species in a particular area
Define Distribution
Where a particular species is within the area you’re investigating
Outline mark-release-recapture
- Capture a sample of the species
- mark them then release them back into their habitat.
- Wait an appropriate length I time
- Take a second sample and count how many of this sample is marked
What is the mark-release-recapture equation?
Number marked in 2nd sample
What assumptions does mark-release-recapture make?
- The mark doesn’t rub off
- there are few, if any births or deaths
- there’s no immigration or emigration
- the marked individuals distribute themselves evenly
Biotic factors affecting population size?
- Disease
- Predation
- Food Source
Abotic factors affecting population size?
- Temperature
- Light
- Humidity
- Water
- pH
Define Intraspecific competition
Competition within the same species
Define Interspecific competition
Competition between different species
What is the Population Growth equation?
(Births+immigration)-(deaths+emigration)
What factors affect birth rates?
- economic conditions
- cultural and religious backgrounds
- social pressures and conditions
- birth control
- political factors
What is the birth rate equation?
Number of births in a year
——————————— x1000
Total pop in the same year
Factors affecting death rates?
- age profile
- life expectancy at birth
- food supply
- safe drinking water/effective sanitation
- medical care
What is the death rate equation?
Number of deaths in a year
———————————- x1000
Total pop in the same year
Describe a demographic transition
- occurs in economically well developed nations
- large increase in life expectancy
- reduction in birth rates
- re-establishes growth curve
What is the population growth rate equation?
Pop change during period
——————————— x100
Pop at start of period
Define Ecosystem
All the organisms living in a particular area with all biotic and abiotic conditions
