Understanding Biological Classification: Identifying Pisces

The question asks us to identify which of the given options belongs to the group 'Pisces'. In biological classification, Pisces refers to the diverse group of aquatic vertebrates commonly known as fish.

Let's examine each option provided:

• Dogfish: Dogfish are small sharks. Sharks are a type of fish belonging to the class Chondrichthyes (cartilaginous fish). Chondrichthyes is part of the superclass Pisces. Therefore, a dogfish is a fish and belongs to Pisces.
• Jellyfish: Jellyfish are marine invertebrates. They belong to the phylum Cnidaria, which includes sea anemones and corals. Jellyfish do not have a backbone, gills, or fins like fish do. They are not fish and do not belong to Pisces.
• Silverfish: Silverfish are small, wingless insects. They are commonly found in homes, feeding on paper and starches. Insects belong to the phylum Arthropoda, class Insecta. They are not fish and do not belong to Pisces.
• Starfish: Starfish, also known as sea stars, are marine invertebrates. They belong to the phylum Echinodermata, which also includes sea urchins and sea cucumbers. Starfish have radial symmetry and tube feet. They are not fish and do not belong to Pisces.

Based on the examination of each option, only the dogfish is classified as a fish and thus belongs to the group Pisces.

Here is a summary of the classifications:

Therefore, the organism that belongs to 'Pisces' among the given options is the Dogfish.

Revision Table: Pisces Identification

Reviewing the key characteristics helps in differentiating between true fish (Pisces) and other aquatic or similarly named organisms.

Additional Information on Pisces and Fish Classification

The superclass Pisces includes all organisms commonly referred to as fish. They are primarily aquatic vertebrates characterized by:

• Presence of gills for respiration throughout life.
• Limbs, if present, are in the form of fins.
• Usually ectothermic (cold-blooded).
• Body covered with scales (though some, like certain catfish and sharks, may lack typical scales).
• Streamlined body shape for efficient movement in water.

Pisces is traditionally divided into several classes, including:

• Chondrichthyes: Cartilaginous fish like sharks, rays, and skates. Dogfish belongs here.
• Osteichthyes: Bony fish, which make up the vast majority of fish species. This includes ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii).

It's important to note that the term 'Pisces' is often used in an ecological or informal sense rather than as a strict, modern taxonomic class, but it effectively groups all fish together for general understanding.