Cephalopods are a diverse class of marine molluscs that includes octopuses, squids, cuttlefish, and nautiluses. This lesson introduces their defining features, living groups, global distribution, and long evolutionary history.
The name Cephalopoda comes from Greek words meaning “head-feet.” In these molluscs, the foot is modified into muscular arms or tentacles surrounding the mouth. Cephalopods also have bilateral body symmetry and a prominent head. Fishers sometimes call them inkfish because many species can release ink to confuse predators. The scientific study of cephalopods is called teuthology, a branch of malacology.
All flashcards
What are cephalopods?
Marine molluscs with bilateral symmetry, a prominent head, and arms or tentacles derived from the foot.
What is teuthology?
Teuthology is the study of cephalopods and a branch of malacology, the study of molluscs.
Which animals belong to Coleoidea?
Coleoidea includes octopuses, squids, and cuttlefish; their shell is internalized or absent.
Where are cephalopods found?
They occur throughout the world's oceans, from surface waters to very deep ocean zones. Their diversity is generally highest in tropical waters and lower toward the poles.
What are ammonites?
Ammonites are extinct cephalopods in the subclass Ammonoidea.
Quiz questions
What distinguishes a closed circulatory system in cephalopods?Answer: Blood travels through vessels rather than freely bathing organs in open body spaces.
How do squid and cuttlefish appendages generally differ from those of octopuses?Answer: They generally have eight arms and two longer tentacles.
What do chromatophores do in cephalopod skin?Answer: They expand or contract pigment-containing cells to alter visible color and pattern.
What is a pseudomorph in cephalopod defense?Answer: An ink-and-mucus decoy that resembles the escaping animal.
In many cephalopods, what is the function of the hectocotylus?Answer: It transfers sperm packets from the male to the female.
Based on the Wikipedia article Cephalopod, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.