Question

What is the linear pattern of eating and being eaten, which can always be traced back to producers, called?

• A. Food web
• B. Food chain
• C. Trophic level
• D. Trophic organization

Answer 1

Answer:

B. Food chain

Understanding the Food Chain

• A food chain is a linear sequence showing how energy is transferred from one living organism to another by the act of eating and being eaten. It illustrates the feeding relationship between different organisms in an ecosystem.
• It always begins with producers, which are organisms that produce their own food, primarily through photosynthesis (e.g., plants, algae).
• The energy flow in a food chain is unidirectional, moving from lower trophic levels to higher trophic levels.
• Each step in a food chain is called a trophic level. Organisms at higher trophic levels feed on organisms from lower trophic levels.

Components of a Food Chain:

• Producers (Autotrophs): These form the first trophic level. They convert solar energy into chemical energy (e.g., grass, trees).
• Primary Consumers (Herbivores): These form the second trophic level. They feed directly on producers (e.g., deer, rabbits, insects).
• Secondary Consumers (Primary Carnivores/Omnivores): These form the third trophic level. They feed on primary consumers (e.g., foxes, small birds eating insects).
• Tertiary Consumers (Secondary Carnivores/Omnivores): These form the fourth trophic level. They feed on secondary consumers (e.g., eagles, wolves).
• Quaternary Consumers (Tertiary Carnivores): In some longer food chains, these feed on tertiary consumers.
• Decomposers: While not typically part of the linear feeding chain, decomposers (bacteria and fungi) break down dead organic matter from all trophic levels, returning nutrients to the ecosystem. They are crucial for nutrient cycling.

Key Facts for Competitive Exams:

• The concept of the food chain was introduced by the Arab scientist Al-Jahiz in the 10th century and later popularized in modern ecology by Charles Elton in 1927.
• Most ecosystems have multiple interconnected food chains, forming a complex food web. A food web provides more stability to an ecosystem than a single food chain.
• The transfer of energy from one trophic level to the next is inefficient, typically only about 10% of the energy is transferred. This is known as the 10% Law of Energy Transfer or Lindeman's Law (proposed by Raymond Lindeman in 1942). The remaining 90% is lost as heat during metabolic activities.
• Due to the 10% law, the number of individuals and the total biomass generally decrease at successive trophic levels, leading to ecological pyramids (pyramid of numbers, pyramid of biomass, pyramid of energy). The pyramid of energy is always upright.
• Two main types of food chains are:
  • Grazing Food Chain: Starts with producers (e.g., grass → deer → tiger).
  • Detritus Food Chain: Starts with dead organic matter or detritus (e.g., dead leaves → detritivores like earthworms → their predators).
• The phenomenon of increasing concentration of toxic substances (like DDT or mercury) at successive trophic levels is called biomagnification or bioamplification.