Age structure Knowledge-Based Practice

Questions

1. 1.

   In population ecology, why can two populations of the same species with identical overall sizes and environmental conditions display substantially different population growth rates?

   • A) One population has an altered carrying capacity that eliminates all density-dependent limiting factors.
   • B) Their age structures differ, resulting in different proportions of individuals in their reproductive years.
   • C) Natural selection operates exclusively on populations that have achieved an equal sex ratio.
   • D) Interspecific competition affects only populations composed entirely of post-reproductive individuals.
2. 2.

   Which demographic phenomenon describes the continued growth of a biological population following a reduction in fertility rates to replacement level, driven by a large proportion of individuals entering their reproductive years from the pre-reproductive cohort?

   • A) Population momentum
   • B) Demographic transition
   • C) Carrying capacity overshoot
   • D) Density-dependent compensation
3. 3.

   In an ecological population maintaining a stable size with approximately zero population growth, which distribution of demographic age cohorts is typically observed?

   • A) A post-reproductive cohort that substantially outnumbers all younger age groups combined
   • B) A pre-reproductive cohort that is significantly smaller than the post-reproductive cohort
   • C) A pre-reproductive cohort that vastly exceeds the reproductive cohort, creating a rapidly expanding base
   • D) A pre-reproductive cohort and reproductive cohort of approximately equal proportions
4. 4.

   What demographic trend is typically expected for a biological population whose age structure displays a significantly smaller pre-reproductive cohort compared to its reproductive and post-reproductive cohorts?

   • A) A sudden shift toward exponential growth driven by high post-reproductive survivorship
   • B) Long-term population stability maintained by an expanding generation time
   • C) A rapid surge in the birth rate due to a reduced density of juvenile competitors
   • D) A gradual decline in population size because fewer individuals will mature to replace the current breeding adults
5. 5.

   Which age structure characteristic most reliably indicates that a biological population is positioned for rapid growth in the near future?

   • A) A high proportion of individuals in the prereproductive cohort relative to the reproductive cohort
   • B) An approximately equal distribution of individuals across prereproductive and reproductive cohorts
   • C) A predominantly postreproductive population with a narrow prereproductive base
   • D) A constriction in the youngest age classes accompanied by an expanded postreproductive class

Answers and step-by-step solutions appear after you finish the test.