Q. Which one of the following is a filter feeder?

Explanation : 

Filter Feeders: The Oyster Example

Filter feeders are organisms that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Among the options provided, the oyster is the filter feeder.

Oysters are bivalve mollusks that live in marine or brackish habitats. They have specialized gills that work as a filtration system. Water is drawn over the gills through the beating of cilia, and particles in the water, including plankton and organic matter, are trapped in mucus on the gills. The mucus with the trapped food is then transported to the oyster’s mouth for consumption. This method of feeding allows oysters to process large volumes of water and extract the nutrients they need to survive.

Feeding Strategies of Other Aquatic Animals

The other options listed do not employ filter feeding as their primary method of feeding:

• Catfish are bottom-dwellers that use a variety of feeding strategies, including scavenging and predation. Some species may sift through sediment to find food, but they do not filter feed in the same way oysters do.
• Octopuses are predators that typically hunt live prey, such as crustaceans and small fish, using their arms and suckers to capture them.
• Pelicans are birds that feed primarily by scooping up fish in their large bill pouches while swimming at the surface or by plunge-diving.

Therefore, the correct answer is the oyster, as it is the only filter feeder among the options provided.