1.2-c) Population Dynamics

Question 1

• Describe population density and what role density-dependent factors plays within a population.

Answer 1

• The population density
  is the number of organisms in a specific area.
  ➞ The density of a population can impact how the population is impacted by certain factors.
• Density dependent factors
  reduce a population when numbers are high and allow the population to increase when numbers are low.

Question 2

• Explain the role of GRAZING as a density dependent factor.

Answer 2

• Grazing
  is the process by which a herbivore (or omnivore) feeds on plants.
  ➞ Grazings can be either generalists or specialists.
• Generalists:
  ➞ can survive on a wide variety of plants
• Specialists:
  ➞ can only survive on one (e.g. pandas)

Question 3

• Explain the role of COMPETITION as a density dependent factor.

Answer 3

• Competition
  occurs when organisms are competing for the same resource(s).
• When resources are limited, competition will reduce the size of the population.
  ➞ Only the fittest (most well adapted) will be expected to survive.

Question 4

• Explain the role of INTRASPECIFIC COMPETITION as a density dependent factor.

Answer 4

• Intraspecific competition
  occurs when individuals of the SAME species are competing for the same resource(s).
  ➞ This includes competition for:
  1. Mates
  2. Space (territory)
  3. Food
• Intraspecific competition is intense because the organisms occupy the same niche so are competing for an identical set of resources.

Question 5

• Explain the role of INTERSPECIFIC COMPETITION as a density-dependent factor.

Answer 5

• Interspecific competition
  occurs when organisms from DIFFERENT species are competing for the same resource(s).
• The species less well-adapted to the niche must either adapt or die.
  ➞ This is referred to as the competitve exclusion principle.
• (i.e. lions will compete with hyenas, leopards and cheetah for prey)

Question 6

• Explain the role of PARASITISM as a density-dependent factor.

Answer 6

• In a parasitic relationship, one species benefits at the expense of the other species.

Question 7

• Explain the role of PREDATION as a density dependent factor.

Answer 7

• Predation
  is the biological interaction where a predator consumes a prey species.
• Predation is an essential part of ecosystem management because it controls the number of primary consumers.