Which term refers to jawless fishes?

Prepare for the IB Marine Science SL Exam. Use flashcards and multiple-choice questions with detailed explanations. Master marine ecosystems, ocean currents, and biological resources for success!

Multiple Choice

Which term refers to jawless fishes?

Explanation:
Agnatha refers to jawless fishes. The name, from Greek, means “without jaws,” describing a group of early vertebrates that lack hinged jaws. This includes creatures like lampreys and hagfish, which have simple, mostly cartilaginous structures and a round mouth used for suction rather than biting with jaws. They are considered primitive vertebrates (cyclostomes) and illustrate an early stage in vertebrate evolution before jaws evolved. The other options don’t describe a group of fishes: Animal is a broad category, Plankton Net is sampling equipment, and Sea Grass is a habitat.

Agnatha refers to jawless fishes. The name, from Greek, means “without jaws,” describing a group of early vertebrates that lack hinged jaws. This includes creatures like lampreys and hagfish, which have simple, mostly cartilaginous structures and a round mouth used for suction rather than biting with jaws. They are considered primitive vertebrates (cyclostomes) and illustrate an early stage in vertebrate evolution before jaws evolved. The other options don’t describe a group of fishes: Animal is a broad category, Plankton Net is sampling equipment, and Sea Grass is a habitat.

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