Question

Choose the false statement regarding the role of temperature as an abiotic factor in the ecosystem.

• A. Temperature plays a vital role in plant and animal phenology and its distribution
• B. The distribution of vegetation of the earth is largely dependent on temperature
• C. It affects transpiration, photosynthesis but not respiration
• D. Chemical and metabolic reactions are all responsive to optimum temperature

Answer 1

The correct option is C It affects transpiration, photosynthesis but not respiration

Phenology is derived from a Greek word called phainō which means to show or appear. So, this term refers to the study of periodic plant and animal life-cycle events
that are influenced by seasonal variations of temperature among other factors. The distribution of vegetation on Earth is dependent on temperature. Tropical rainforests at 0-20 degrees latitude with a mean temperature of 40 to 50 degree Celsius house the densest flora and fauna. They contain more than half of the terrestrial species on earth. In contrast, tundra regions between 60 to 80 degree latitudes are dominated by mosses, lichens and low growing shrubs and have low biodiversity, containing only 3 % of the world's flora.
Temperature affects transpiration, photosynthesis and respiration. At warmer temperatures, water molecules move faster, and the rate of evaporation from the stomata is also much faster. Secondly, the water-holding capacity of warm air is greater than that of cold air. At medium temperatures, the photosynthetic enzymes work at their optimum level. Increase in temperature enhances the rate of cellular respiration. It is so because heat speeds up the reactions. As the kinetic energy, rate of chemical reactions also speeds up, the rate of cellular respiration increases. When temperature decreases, in order to conserve energy, cellular processes slow down. So option (iii) is incorrect.