Problem 176 - Objective Biology for NEET

Question

Which fish possess electric organs? (a) Scoliodon (dog fish) (b) Trygon (c) Torpedo (d) Pristis (saw fish)

Step-by-Step Solution

Answer

(c) Torpedo

Step 1: Analyze Scoliodon (dog fish)

Start by researching about Scoliodon fish, whether it has electric organs or not. Scoliodon, also known as a dog fish, does not possess electric organs.

Step 2: Analyze Trygon

Next, research about Trygon fish. A Trygon, commonly known as a stingray, also doesn't have electric organs.

Step 3: Analyze Torpedo

Then, find information about Torpedo fish. The Torpedo fish is known to have electric organs.

Step 4: Analyze Pristis (saw fish)

Lastly, research about Pristis fish. Pristis, also known as a saw fish, does not have electric organs.

Key Concepts

Scoliodon

The Scoliodon, commonly referred to as the dogfish, is a type of shark. It's important to note that although it's a fascinating marine creature, Scoliodon does not possess electric organs. Sharks are generally more known for their streamlined bodies and hunting prowess, rather than electric capabilities. Their sensory systems are adapted for detecting vibrations and movements in water but not for generating electricity. The presence of electroreceptors known as ampullae of Lorenzini allows them to sense electrical fields, yet they do not produce electricity themselves.

Torpedo

The Torpedo fish, often called the electric ray, is truly remarkable in the aquatic world for possessing electric organs. These organs are used to produce electric shocks, serving both defense and predation purposes. The Torpedo's electric organs are located at the base of the fish's pectoral fins. They are made up of specialized cells called electrocytes, which store electric charge and release it in bursts. The shocks can be varying in intensity, making the Torpedo unique among fish with electric capabilities. This adaptation allows it to stun prey, deterring potential threats effectively.

Pristis

Pristis, also known as the sawfish, is quite distinct due to its long, saw-like snout. Despite its intriguing appearance and name, Pristis does not have electric organs. Instead, this feature makes it highly skilled at sensing and attacking prey. Its rostrum is lined with tiny electroreceptors that help detect movements and pulses in the water, but Pristis does not generate electricity. The sawfish uses its saw to dig, stun, and hunt fish in its habitat, while relying on more traditional hunting techniques for survival.

Trygon

Trygon, commonly known as the stingray, shares similar habitats with other electric and non-electric fish. Though related to electric rays like the Torpedo, the Trygon does not possess electric organs. Instead, stingrays rely on their tails equipped with venomous spines for defense. These spines deliver painful stings, which can deter predators effectively. Their flat bodies enable them to camouflage themselves in the seabed, hiding from predators and surprising their prey. Unlike electric rays, Trygon relies on stealth and speed rather than electric shocks to capture prey.

Electric Organs in Fish

Electric organs in fish are a fascinating evolutionary adaptation found in a few unique species. Fish with these organs utilize electricity for various purposes such as hunting, protection, navigation, and communication.

• The most well-known electric fish is the electric eel, capable of delivering shocks strong enough to take down prey.
• Electric rays, like the Torpedo, are another well-known group possessing electric organs.
• These adaptations can also allow fish to communicate, as some species use electrical pulses to relay information about their environment or mating readiness.

Electric organs are composed of electrocytes, specialized cells that produce electricity by accumulating and releasing ionic charges. Not all marine creatures with the ability to sense electric fields, known as electroreception, have the biology to generate them actively. This makes electric organs an extraordinary development in the animal kingdom.