BIO 105 Home
Questions | Answers

1. Definitions:

  • Population: all the individuals of a species living together in the same area.
  • Population Density: population size (# individuals) per a given sized area.
  • Rate of Population Change: (Birth rate + Immigration rate) – (Death rate + Emigration rate).

2. Definitions:

  • Biotic Potential: maximum population growth rate.
  • Resistance Factors: factors that decrease population growth rate.
  • Density-dependent Factors: effects influenced by population size.
  • Density-independent Factors: effects are independent of population size.

3. Examples of density-dependent factors: disease, competition, predation. Examples of density independent factors: avalanche, fire, severe weather.

4. Definitions:

  • Linear Growth: Population grows by a fixed number (e.g., 100 animals/yr); produces a straight line on a graph
  • Exponential Growth: J Curve. Population grows by a percentage; J curve
  • Logistic Growth: S curve. Population shows initial exponential growth and then stabilizes its population size near its carrying capacity.
  • Overshoot and Crash: population size rises and then falls abruptly.

5. Carrying Capacity: the maximum number of individuals an area can support forever. When a population exceeds its carrying capacity it is using its resources faster than they replenish so the resources become depleted, and the population eventually crashes.

6. Minimum Viable Population: the smallest population size that is sustainable.