Ecology Of Populations 2 — Questions and Answers
Question 1: Which term describes the maximum population size an environment can sustain indefinitely given available resources?
- Carrying capacity (Correct answer)
- Biotic potential
- Population density
- Replacement rate
Correct answer: Carrying capacity
Carrying capacity (K) is the maximum number of individuals an environment can support long-term given its limiting resources.
Question 2: A population grows from 200 to 260 individuals in one year. What is the per capita growth rate (r) for that year?
- 0.30 (Correct answer)
- 0.23
- 0.60
- 0.13
Correct answer: 0.30
Per capita growth rate r = (260 - 200) / 200 = 60 / 200 = 0.30 per individual per year.
Question 3: In a survivorship curve, a Type I curve is characteristic of species that:
- Produce many offspring with little parental care
- Experience constant mortality at all ages
- Have low juvenile mortality and high adult mortality (Correct answer)
- Die mostly as juveniles before reaching adulthood
Correct answer: Have low juvenile mortality and high adult mortality
Type I survivorship curves show most individuals surviving to old age, then dying rapidly, typical of large mammals including humans.
Question 4: Which of the following is an example of a density-independent limiting factor for a population?
- Food competition among individuals
- Predation pressure that increases with density
- A sudden wildfire destroying habitat (Correct answer)
- Disease spread facilitated by crowding
Correct answer: A sudden wildfire destroying habitat
Density-independent factors like natural disasters affect populations regardless of how many individuals are present.
Question 5: What does the demographic concept of 'generation time' refer to?
- The average age at which individuals die
- The average time between birth and first reproduction (Correct answer)
- The total reproductive lifespan of an individual
- The interval between population censuses
Correct answer: The average time between birth and first reproduction
Generation time is the average age at which individuals first reproduce, influencing how quickly a population can grow.
Question 6: Which population age structure indicates a rapidly growing population?
- A narrow base with a wide top pyramid
- An even distribution across all age classes
- A broad base tapering to a narrow top (Correct answer)
- A narrow base and narrow top with a wide middle
Correct answer: A broad base tapering to a narrow top
A broad-based age pyramid indicates many young individuals relative to older ones, signaling rapid future population growth.
Question 7: The Allee effect describes a phenomenon where:
- Population growth accelerates as density increases
- Per capita growth rate decreases at very low population densities (Correct answer)
- Carrying capacity rises when predators are removed
- Emigration rate exceeds immigration at high densities
Correct answer: Per capita growth rate decreases at very low population densities
The Allee effect occurs when per capita fitness or growth rate declines at low densities due to reduced mate-finding, cooperation, or predator defense.
Ecology Of Populations 2
Which term describes the maximum population size an environment can sustain indefinitely given available resources?