Many candidates could properly define decomposers and scavengers and give appropriate examples but
in defining decomposers a lot of candidates omitted to say that they secrete enzymes into the substrate.
Most candidates could correctly state the source of energy in an ecosystems as well as the organisms that
receive the most amount of energy namely sunlight/sun/sola/energy and producers/green plants but could
not state the reasons. In stating the organisms which receive the most amount of energy some candidates
merely wrote plants rather than green plants and so lost the score.
Reasons for saying that producers receive the most amount of energy in the ecosystem include
- Producers absorb sunlight energy; and convert it into chemical energy through the process of
photosynthesis'; not all the energy which the plant gets from sunlight is converted to chemical
energy; some is lost through respiration/other metabolic activities;
- All consumers depend directly or indirectly on plants for food;
- Not all parts of the plant are eaten by consumer;
- Only a fraction of the energy gotten by plants is passed to consumers.
Only a few candidates could construct a detritus food chain. Most candidates made chains that begun
with a producer and many candidates drew line linking the organisms which did not have arrow heads and
so could not score. Expected answers include:
Detritus food chain
Begin with detritus/correctly named detritus
→ Detritivore (earth worm, fly, maggots, woodlice)
→ Chichken → snake → hawk.