AAquatic and Terrestrial
BGrazing and Detritus
CProducer and Consumer
DUpright and Inverted
Answer:
B. Grazing and Detritus
Read Explanation:
Food Chains: An Overview
A food chain illustrates the feeding relationships between different organisms in an ecosystem, showing how energy is transferred from one trophic level to another.
It depicts the sequence of who eats whom, starting with primary producers and ending with apex predators or decomposers.
Grazing Food Chain (GFC)
Starting Point and Energy Source
The Grazing Food Chain (GFC) begins with producers, primarily green plants (autotrophs) that synthesize their own food through photosynthesis.
Its primary energy source is solar energy, captured by plants.
Energy Flow
Energy flows from producers to primary consumers (herbivores) like deer, grasshoppers, or rabbits, which feed on plants.
Subsequently, energy is transferred to secondary consumers (carnivores or omnivores) that prey on herbivores, and then to tertiary consumers (top carnivores).
Examples
A common example is Grass → Deer → Tiger or Algae → Zooplankton → Fish → Heron.
Key Characteristics for Exams
It is directly dependent on photosynthesis and sunlight.
Represents the flow of energy through living organisms primarily by consumption.
Detritus Food Chain (DFC)
Starting Point and Energy Source
The Detritus Food Chain (DFC) begins with dead organic matter (detritus), which includes dead plants, animals, and waste products.
Its energy source is the chemical energy stored in dead organic matter, rather than direct solar energy.
Energy Flow
Detritivores (e.g., earthworms, mites, fungi, bacteria) consume the detritus, breaking down complex organic compounds into simpler ones.
These detritivores are then consumed by predators (e.g., frogs, snakes, birds that eat earthworms), forming the subsequent links in the chain.
Examples
A typical example is Dead Leaves → Earthworm → Blackbird or Dead Wood → Termites → Anteater.
Key Characteristics for Exams
Plays a crucial role in nutrient cycling, returning essential minerals back to the soil or water, making them available for producers.
In many terrestrial and aquatic ecosystems, a much larger fraction of energy flows through the detritus food chain than through the grazing food chain.
Decomposers (bacteria and fungi) are vital components of the DFC, responsible for breaking down complex organic matter.
Interconnection and Importance
Both grazing and detritus food chains are interconnected within an ecosystem. Organisms from the grazing food chain eventually contribute to the detritus pool upon their death.
While the GFC is often visualized, the DFC is equally, if not more, important for the overall functioning and stability of most ecosystems, particularly in nutrient recycling