Species diversity Knowledge-Based Download PDF

Questions

1. 1.

   According to the intermediate disturbance hypothesis, which ecological condition explains why biological communities subject to moderate levels of disturbance maintain higher species diversity than those with very low disturbance?

   • A) It prevents competitively dominant species from excluding competitively inferior species while allowing colonizers to persist.
   • B) It permanently eliminates pioneer species and permits only climax species to survive in the community.
   • C) It stabilizes resource availability so that a single superior competitor can monopolize available niches.
   • D) It generates extreme physiological stress that prevents interspecific competition from taking place entirely.
2. 2.

   Which factor explains why biological communities with high habitat heterogeneity typically exhibit greater species diversity than structurally uniform habitats?

   • A) Structurally uniform habitats eliminate interspecific competition by forcing all organisms into identical trophic roles.
   • B) Diverse microenvironments provide a greater variety of ecological niches, allowing more species to coexist without competitive exclusion.
   • C) Increased spatial complexity reduces primary productivity, which prevents dominant populations from expanding rapidly.
   • D) Structurally complex environments prevent colonization by specialized predators, ensuring unchecked population growth across trophic levels.
3. 3.

   According to ecological principles, how does higher species diversity typically influence a biological community's response to environmental disturbances?

   • A) It reduces overall primary productivity and destabilizes essential nutrient cycles.
   • B) It increases vulnerability to biological invasions by leaving abundant resources unconsumed.
   • C) It enhances community stability and resilience through functional redundancy among species.
   • D) It triggers widespread competitive exclusion that drives most primary producers to extinction.
4. 4.

   How does a marked decrease in species evenness affect the overall species diversity of a biological community if species richness remains constant?

   • A) It decreases the species diversity because the individuals are disproportionately concentrated in a few dominant species.
   • B) It increases the species diversity because the dominant species stabilize the community against competitive exclusion.
   • C) It leaves the species diversity unchanged because diversity depends exclusively on the total number of species present.
   • D) It causes species diversity to fluctuate randomly because evenness does not factor into standard diversity calculations.
5. 5.

   Which two fundamental components must ecologists determine to evaluate the overall species diversity of a biological community?

   • A) Species richness and species evenness
   • B) Total community biomass and net primary productivity
   • C) Geographic range size and average organism size
   • D) Population carrying capacity and intrinsic growth rate