Measuring Populations Flashcards
Give the equation for calculating population growth.
[Births + immigration] - [Deaths + Emigration]
Give an equation for calculating percentage population growth.
Population change at the start / Population change at the end (x100)
Name 3 factors to consider when using a quadrat.
Size of quadrat
No. of samples to measure
Position of quadrats
Why does the size of the quadrat used matter?
Also depends on the size of the area measured.
Why is it important to consider the number of samples you will take when using quadrats?
The larger the sample, the more reflective it is of the population.
Why does the position of quadrats placed matter?
They must be placed randomly to get a representative sample.
What is random sampling and why is it important?
The use of chance methods to select a sample. Important to remove bias.
How do we do random sampling when selecting a place to put quadrats?
Use a random number generator to select coordinates.
What is mark release recapture?
- Sample of species marked
- Released back into their habitat
- Sample recollected and the number of organisms marked calculated
What 2 things does the mark release recapture technique assume?
No migration or change in population has occured.
What is systematic sampling?
Where every nth number of a population is selected.
What is abundance?
The frequency of individuals in a species in a given area.
Give 2 ways of calculating abundance.
Calculate frequency - likelihood of a particular species occurring within a quadrat.
Calculate percentage cover.
Describe how you could use a belt transect to measure abundance.
Place a belt transect throughout a large area.
Place quadrats at regular intervals down the belt.
Count frequency of each individual in the quadrat.
What type of animals are used in mark, release, recapture.
Fast moving animals
