Population dynamics

Question 1

What is a population?

Answer 1

A group of individuals of the same species occupying a given area at a given time; a group of organisms that share a common gene pool.

Question 2

What is a metapopulation?

Answer 2

A group of spatially separated populations linked by dispersal.

Question 3

Define the demography of a population

Answer 3

The characteristics of a population that determine the population’s dynamics; this can include: size, density, distribution, age structure, genetic structure, birth + death rates, immigration and emigration rates, etc.

Question 4

What are three ways we can estimate population abundance?

Answer 4

1. Total counts (only applicable to areas with set, physical boundaries)
2. Estimate absolute numbers (e.g. quadrats, transects, mark-recapture)
3. Measure indices of relative numbers (e.g. trapped animals, faeces, roadkills, hunted animals)

Question 5

Why is population density generally more important than population size?

Answer 5

Population size can only be reliably studied in relatively small or isolated populations. Population density is often easier to quantify and population regulation depends on density-dependent processes.

Question 6

Define dispersion

Answer 6

Dispersion is how individuals are spaced with respect to one another within a population. Three patterns of dispersion are recognised: random, uniform and clumped / aggregated.

Question 7

Define dispersal

Answer 7

Dispersal is a process by which individuals spread away from each other. It can be passive or active, within a population, into a population (immigration) or out of a population (emigration). Natal dispersal (of young animals to avoid inbreeding) and breeding dispersal (of mature animals in search of feeding or breeding opportunities) are examples.

Question 8

Define migration

Answer 8

Migration is a mass directional movement of large numbers of individuals from one location to another. These can happen during breeding seasons, across generations, across habitats, within a lifetime, yearly or daily.

Question 9

Define age structure of a population

Answer 9

Age structure is the relative number of individuals in the population of a given age-class (or life-history stage or size).

Question 10

What can age structure of a population tell us?

Answer 10

As populations ultimately tend towards a stable age distribution, its fluctuations over time can tell us how developed the population is. The age structure can also tell us about the growth rate of the population in the past.