Which organism is NOT a filter feeder?

Step 1: Analyze the question We are asked to find the organism that does NOT feed by filtering. A filter feeder strains small food particles (plankton, detritus) out of water using special structures.

Step 2: Concept Filter feeding (suspension feeding) is common in aquatic organisms. They use gills, bristles, or plates to trap tiny food particles from the water.

Step 3: Check each option

• A. Adult mosquito: Adults do not live in water and do not filter. Females have piercing-sucking mouthparts to feed on blood. Males and females also suck nectar and plant juices. Not a filter feeder.
• B. Copepod: Tiny crustaceans that use their appendages to filter phytoplankton from the water. Filter feeder.
• C. Mosquito larva: Lives in water and uses mouth brushes to sweep and filter microorganisms and organic particles. Filter feeder.
• D. Oyster: A bivalve mollusc that pumps water over its gills and traps food particles in mucus. Filter feeder.
• E. Whale: Baleen whales (such as the blue whale) filter krill and plankton through baleen plates. This is the typical textbook example, so it is classed as a filter feeder.

Step 4: Answer The adult mosquito is the only organism here that does not filter food from water. It feeds by piercing and sucking.

Correct answer: A. Adult mosquito

Exam tip: Remember that the mosquito changes feeding method during its life cycle. The larva filters water, but the adult pierces and sucks. Questions often test this difference between life stages.