Class Cephalopoda Flashcards

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Questions and Answers

Which of the following are included in Class Cephalopoda?

Cuttlefish

Squid

Octopi

All of the above (correct)

Class Cephalopoda are the least advanced mollusca.

False

What are some characteristics of Cephalopoda?

Chambered shell (if present), tentacles surrounding mouth, radula and beak, closed circulatory system, high degree of cephalization, image-forming eyes.

Cephalopoda have a BLANK circulatory system.

closed Signup and view all the answers

What is the Subclass Nautioidea known for?

Having a chambered external shell and being a 'living fossil'. Signup and view all the answers

What are siphuncles?

They connect chambers in the shell and adjust buoyancy. Signup and view all the answers

Siphuncles can withdraw completely into the shell.

False Signup and view all the answers

What is the Subclass Ammonoidea known for?

Being extinct and excellent index fossils. Signup and view all the answers

What are the characteristics of Subclass Coleoidea?

8-10 prehensile arms with suckers, internal shells, and chromatophores. Signup and view all the answers

What do chromatophore organs contain?

Chromatophore cells, iridophore cells, muscle cells, nerve cells. Signup and view all the answers

Chromatophores produce 3 different colors: brown, yellow, & BLANK.

green Signup and view all the answers

How do chromatophores produce different colors?

By contracting and expanding. Signup and view all the answers

What distinguishes Order Sepiodea?

Cuttlefish. Signup and view all the answers

What are the characteristics of Sepiodea?

Body dorso-ventrally flattened, shells internal or absent, 8 short arms, 2 long tentacles. Signup and view all the answers

Cuttlefish bones are characterized as:

Shell, hollow, and with internal chambers. Signup and view all the answers

What does the Order Teuthoida consist of?

The squids. Signup and view all the answers

What are the characteristics of Teuthoida?

8 short arms; 2 long non-retractable tentacles, elongated tubular body. Signup and view all the answers

What is the gladius in Teuthoida?

An internal thin, clear shell. Signup and view all the answers

Teuthoida are the BLANK inverts.

faster Signup and view all the answers

How can Teuthoida use their siphon?

To pump water and change direction. Signup and view all the answers

What is represented by Order Octopoda?

Octopi. Signup and view all the answers

What are the characteristics of Octopoda?

Shell absent, 8 arms, most are benthic. Signup and view all the answers

Where is the Dumbo Octopus found?

In the deep sea. Signup and view all the answers

Cephalopods are hermaphroditic.

False Signup and view all the answers

Study Notes

Class Cephalopoda Overview

Includes cuttlefish, squid, and octopus.
Recognized as the most advanced group within the mollusks.

Distinctive Features of Cephalopoda

Possess a chambered shell (if present) and tentacles surrounding the mouth.
Features a radula and beak, along with a closed circulatory system.
Highly developed neural organization (cephalization) and image-forming eyes.
Contains a large mantle cavity with a muscular funnel (siphon).
Typically features 1-2 pairs of ctenidia (gills) and nephridia (excretory organs).
Carnivorous lifestyle, exhibiting gonochoristic reproduction (separate sexes).

Circulatory System

Cephalopoda have a closed circulatory system enabling faster movement.

Subclass Nautioidea

Solecephalopods with an external chambered shell.
Have pinhole eyes without cornea or lens, and possess 80-90 suckerless tentacles.
Lack chromatophores and ink sac; regarded as "living fossils."

Siphuncles

Structures that connect shell chambers, allowing adjustment of buoyancy by manipulating water and gas content.

Subclass Ammonoidea

Extinct cephalopods that coexisted with dinosaurs and serve as significant index fossils.
Present sexual dimorphism complicates species determination.

Subclass Coleoidea

Comprises cuttlefish, octopuses, and squid, known for advanced adaptations.

Characteristics of Coleoidea

Equipped with 8-10 prehensile arms covered with suckers.
Possess a pair of ctenidia and nephridia; internal shells may be vestigial or absent.
Have well-developed eyes with cornea and lens, along with chromatophores and an ink sac for defense and communication.

Chromatophores

Composed of specialized cells (chromatophore, iridophore, muscle, nerve, and glial cells) for rapid color change via neural control.
Produce colors such as brown, yellow, and other shades by contracting and expanding.

Order Sepiodea

Represents cuttlefish, characterized by a dorsally flattened body, lateral fins, and unique feeding adaptations.

Sepiodea Features

Possess 8 short arms and 2 long feeding tentacles without hooks, targeting fish and crustaceans.
Cuttlefish bones are hollow, with internal chambers aiding in buoyancy control.

Order Teuthoida

Known as squid; recognized for their streamlined body designed for speed.

Teuthoida Characteristics

Comprising 8 short arms and 2 long non-retractable tentacles; possess a vestigial internal shell called the gladius.
Adaptations for pelagic life, with suckers often reinforced with hooks.

Teuthoida Adaptations

Utilize a siphon to propulse and navigate swiftly in water.

Order Octopoda

Represent octopuses, which are recognizable for their unique body structure.

Octopoda Characteristics

Lack a shell, exhibit 8 arms, and typically occupy benthic marine environments.
Primary prey includes mollusks and crustaceans.

Notable Species

The Dumbo octopus thrives in deep-sea habitats, exemplifying cephalopod diversity.

Reproductive Biology

Cephalopods possess separate sexes and are not hermaphroditic, reflecting varied reproductive strategies.

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Description

Explore the fascinating world of the Cephalopoda class of mollusks through these flashcards. Learn about their characteristics, notable members like cuttlefish and octopi, and why they are considered the most advanced mollusks. Perfect for students and enthusiasts looking to deepen their understanding of marine biology.