Unit 2.1d Flashcards
How are populations monitored and what is the point?
They are monitored by estimations or counts of the number of individuals or density of a species on more than one occasion and allow any changes in population to be detected over time.
What are indicator species?
Species in which the presence, absence or abundance can give information on the environmental qualities of a habitat
What does the absence or reduced numbers of an indicator species indicate?
It indicates that the species is susceptible to a factor in the environment
What does the increase or abundance in a species population indicate?
That they are favoured to the conditions
Why mark in individual organism?
To allow populations to be monitored as the mark can help with recapture count or can be used as a method to track the movement of an organism without recapturing it
What are the five ethical methods of marking?
- Metal bands or plastic loops with an individual identifier.
- Metal or plastic tags attached to animal for remote tracking.
- Microchip tags.
- Non-toxic biodegradable paint marks.
- Identifiable section of hair removed
What formula is used to calculate the total population size during marking recapture?
N = MC/R
What does the method of mark and recapture allow?
An estimation of population size
What does the M stand for in the formula N = MC/R?
Marked
What does the C stand for in the formula N = MC/R?
Second sample captured
What does the R stand for in the formula N = MC/R?
It’s the individuals from the second sample that are recaptured
What does the N stand for in the formula N = MC/R?
Total population
What four assumptions are made when estimating population size via mark and recapture?
- Individuals have equal chance of capture.
- No immigration or emigration.
- No birth and death during sample time.
- Individuals marked released can mix fully and randomly with total population.
