Ecosystems Knowledge-Based Practice

Questions

1. 1.

   Which of the following characteristics distinguishes secondary succession from primary succession in an ecosystem?

   • A) It begins in an area where soil and organic matter remain intact after a disturbance.
   • B) It initiates on newly exposed bare rock surfaces that have never supported living organisms.
   • C) It entirely bypasses the pioneer stage to immediately establish a mature climax community.
   • D) It leads to an ecosystem permanently devoid of autotrophic producers.
2. 2.

   Which of the following statements best describes the role of a keystone species within an ecosystem?

   • A) It exerts a disproportionately large effect on the community structure and stability relative to its actual abundance or total biomass.
   • B) It possesses the largest total biomass and numerically dominates all other species present in the ecosystem.
   • C) It functions as the primary producer that converts solar energy into chemical energy to establish the trophic base.
   • D) It acts as the initial pioneer species that colonizes newly formed, barren substrate during primary ecological succession.
3. 3.

   Which of the following correctly pairs a biotic factor with an abiotic factor found in a typical pond ecosystem?

   • A) Phytoplankton and aquatic snails
   • B) Solar radiation and water temperature
   • C) Decomposing bacteria and predatory fish
   • D) Water lilies and dissolved mineral nutrients
4. 4.

   Which of the following statements correctly describes how energy and chemical nutrients move through an ecosystem?

   • A) Both energy and chemical nutrients follow a unidirectional pathway through the ecosystem without being recycled.
   • B) Both energy and chemical nutrients cycle indefinitely between trophic levels and the physical environment.
   • C) Energy is recycled continuously among trophic levels, whereas chemical nutrients dissipate irreversibly as heat.
   • D) Energy flows unidirectionally and dissipates as heat, whereas chemical nutrients are continuously recycled.
5. 5.

   Which of the following best defines an ecosystem?

   • A) A biological community of interacting organisms along with their physical, non-living environment
   • B) A group of individuals belonging to the same species that live and reproduce in a defined area
   • C) The collection of all non-living physical factors, such as climate, soil, and water, in a geographic region
   • D) An assemblage of different interacting populations of organisms, excluding all physical surroundings

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