Cephalopoda Class Flashcards

Phylum and Classification

• Class Cephalopoda belongs to the phylum Mollusca.
• Known as "head foot," referring to their distinctive body structure.

Characteristics of Cephalopods

• Considered one of the most advanced groups of invertebrates.
• Includes species such as octopus, squid, cuttlefish, and chambered Nautilus.
• Most are active hunters and have typically lost their external shell.

Body Structure and Movement

• The mantle tissue is thickened and muscular, encasing the visceral mass for protection and enabling rapid movement.
• Utilizes jet propulsion for quick short-distance movement.
• Can release ink to obscure vision of predators during escape.

Arms and Tentacles Adaptations

• The cephalopod foot is modified into arms and tentacles.
• Octopuses possess 8 arms lined with suckers for grasping and manipulation.
• Squids have 8 short arms and 2 longer tentacles, used primarily for capturing prey.

Feeding Mechanism

• The centralized arrangement of arms surrounds a beak that allows cephalopods to bite and consume prey.

Species Types

• Pelagic species include squid, Nautilus, and cuttlefish, which live in open water.
• Benthic species such as octopus inhabit the ocean floor.
• Both groups exhibit high cephalization, characterized by well-developed eyes and a centralized nervous system.

Swimming and Support Structures

• The torpedo shape of squids enhances swimming efficiency.
• Squids possess a stiff internal support structure called a pen.
• The mantle of a squid morphs into two fins that aid in swimming.