AH Biology - Unit 2 - KA1(d) - Monitoring Populations

Why is it crucial to monitor populations?

It is crucial to monitor populations to understand environmental conditions and changes to them over time.

What are indicator species?

Indicator species are species that are either susceptible or favoured by particular environmental conditions.

What does the presence, absence, or abundance of indicator species indicate?

The presence, absence, or abundance of indicator species indicates information about the environmental quality and pollution levels. For example, lichen types can be used to indicate SO₂ levels in the air.

What will susceptible indicator species be if the factor they are susceptible to is present in the environment?

Susceptible indicator species will be absent or in reduced numbers if the factor they are susceptible to is present in the environment.

What will favoured indicator species be if the factor they are favoured by is present in the environment?

Favoured indicator species will be abundant or in higher numbers if the factor they are favoured by is present in the environment.

What is the method for marking and recapturing to estimate population size?

The method for marking and recapturing to estimate population size is:

• A sample of the population is captured, marked, and released.

• After a period of time, a second sample is captured.

• The number of individuals recaptured is counted.

• Population size is estimated using the formula N=(MC)/R

What is the formula for marking and recapturing to estimate population size?

The formula for marking and recapturing to estimate population size is N=(MC)/R

What does the N represent in N=(MC)/R

The N in N=(MC)/R represents population size.

What does the M in N=(MC)/R represent?

The M in N=(MC)/R represents the sample of the population that have been captured, marked, and released.

What does the C in N=(MC)/R represent?

The C in N=(MC)/R represents the second sample captured.

What does the R in N=(MC)/R represent?

The R in N=(MC)/R represents the number of individuals recaptured.

What does the mark and recapture method assume?

The mark and recapture method assumes that:

• All individuals have an equal chance of capture

• There is no immigration or emigration

• Individuals captured and released can mix fully and randomly with the total population.

What is it crucial to consider when marking individuals?

When marking individuals, it is crucial that whatever method of marking is used has a minimal impact on the species being studied and does not prevent it from behaving normally or reduce its chances of survival. However, it must still be clear enough to be seen in subsequent captures.

What are different methods of marking?

Different methods of marking are:

• Ringing

• Tagging

• Surgical implantation

• Painting

• Hair clipping