Question

What is the primary source of energy in almost all natural ecosystems?

• A. A) Geothermal energy
• B. B) Chemical energy
• C. C) Radiant energy from the sun
• D. D) Tidal energy

Answer 1

Answer:

C. C) Radiant energy from the sun

Primary Energy Source in Ecosystems: Radiant Energy from the Sun

• The primary source of energy for almost all natural ecosystems on Earth is radiant energy, which comes directly from the Sun.
• This solar energy is captured by producers, primarily green plants, algae, and some bacteria, through a vital process called photosynthesis.
• During photosynthesis, light energy is converted into chemical energy (glucose), which forms the base of nearly all food chains and food webs.
• Photosynthesis Equation: 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ (glucose) + 6O₂. This equation highlights the conversion of carbon dioxide and water into glucose and oxygen using light energy.
• Organisms that produce their own food using light energy are known as photoautotrophs (e.g., plants, cyanobacteria).
• Energy then flows from these producers to various consumers (herbivores, carnivores, omnivores) and decomposers within the ecosystem.

• Exceptions to Solar Energy Reliance:

  • While solar energy is dominant, a notable exception is deep-sea hydrothermal vent ecosystems. Here, the primary energy source is chemical energy, utilized by chemoautotrophs through a process called chemosynthesis.
  • Chemosynthesis involves the oxidation of inorganic compounds (like hydrogen sulfide) to produce energy, supporting unique food webs independent of sunlight.
• The continuous influx of solar energy is crucial for sustaining life, driving the water cycle, and influencing climate patterns on Earth.
• Understanding energy flow is fundamental to ecology and forms the basis for studying trophic levels and productivity in ecosystems.