Components of Ecosystem: Biotic and Abiotic MCQ - Practice Questions with Answers

An ecosystem has two major components—biotic and abiotic.

Biotic (Living) Components:

• Plants, animals and micro-organisms having different nutritional behaviour constitute the biotic components of an ecosystem.

Producers:

• Producers are mainly chlorophyll bearing green plants (photoautotrophs) which can synthesize their food in presence of sunlight making use of and water through the process of photosynthesis. 
• Chemosynthetic organisms or chemo-autotrophs can also synthesize some organic matter by the oxidation of certain chemicals in absence of sunlight.

Consumers:

• Consumers consume the matter built up by the producers. They utilise, rearrange and decompose complex materials.
• Consumers are of the following types:
  • Herbivores: They feed directly on producers and hence are known as primary consumers, e.g., rabbit, deer, cattle, insects etc.
  • Carnivores: They feed on other consumers. If they feed on herbivores, they are called secondary consumers (e.g., frog, birds, cat) and if they prey on other carnivores (snake, peacock), they are known as tertiary consumers. Lions, tigers etc. which cannot be preyed are called top carnivores since they occupy top position in the food chain.
  • Omnivores: They feed both on plants and animals, e.g., rats, fox, birds and man.
  • Detritivores: They feed on partially decomposed matter such as termites, ants, crabs, earthworms etc.
  • Decomposers: They derive their nutrition by breaking down complex organic compounds and releasing inorganic nutrients into the environment, making them available again to producers.
     

• Climatic regime:
  • Precipitation, temperature, sunlight, intensity of solar flux, wind etc. have a strong influence on the ecosystem.
• Inorganic substances:
  • These are C, N, H, O, P, S involved in material cycles. 
  • The amount of these substances present in an ecosystem is known as standing state or standing quality.
• Organic Substances:
  • Carbohydrates, proteins, lipids and humic substances link the abiotic components with the biotic components. 
  • All the biotic and abiotic components of an ecosystem are influenced by each other and are linked together through energy flow and matter cycling.