Biotic and abiotic factors Knowledge-Based Download PDF

Questions

1. 1.

   In an ecosystem, matter continuously cycles between living organisms and the physical environment. Which of the following processes directly transfers carbon from a biotic component to an abiotic reservoir?

   • A) Primary consumers assimilating organic carbon by feeding on plant foliage
   • B) Autotrophs incorporating inorganic carbon dioxide into sugars during photosynthesis
   • C) Decomposers absorbing organic nutrients from fallen leaf litter
   • D) Aerobic organisms releasing carbon dioxide gas into the atmosphere via cellular respiration
2. 2.

   Which of the following represents an abiotic factor that limits the growth of plants living on the floor of a dense temperate forest?

   • A) The intensity of sunlight penetrating the canopy
   • B) The density of overlapping tree leaves in the canopy
   • C) The presence of leaf-eating herbivorous insects
   • D) The competition from surrounding woody shrubs
3. 3.

   Ecosystems are shaped by both living components and non-living environmental variables. Which of the following scenarios describes an abiotic factor directly influencing a biotic factor?

   • A) An increase in soil nitrate concentration enhancing the growth rate of native grasses
   • B) A surge in herbivore density causing a sharp decline in local shrub biomass
   • C) A parasitic fungal infection reducing the survival rate of an amphibian population
   • D) An increase in apex predator abundance lowering the population of grazing mammals
4. 4.

   Which of the following statements correctly distinguishes between biotic and abiotic factors in an ecosystem?

   • A) Biotic factors consist of non-living chemical substances, whereas abiotic factors include all living organisms and their biological remains.
   • B) Biotic factors encompass living organisms and their biological interactions, whereas abiotic factors are the non-living physical and chemical components of the environment.
   • C) Biotic factors refer to external climatic variables like sunlight and temperature, whereas abiotic factors refer exclusively to autotrophs and decomposers.
   • D) Biotic factors remain static over ecological timescales, whereas abiotic factors actively reproduce and adapt through natural selection.
5. 5.

   Which of the following is classified as a biotic factor within a freshwater ecosystem?

   • A) Decomposing bacteria breaking down organic matter
   • B) Dissolved oxygen concentration in the water column
   • C) Intensity of sunlight penetrating the surface layer
   • D) Annual variation in water temperature