Phylum Mollusca Lecture Review

Vocabulary flashcards covering essential terms and concepts related to Phylum Mollusca.

Phylum Mollusca

A diverse group of invertebrates with approximately 100,000 species, characterized by a triploblastic body plan, bilateral symmetry, and a coelom.

Lophotrochozoa

A clade within the animal kingdom that includes Phylum Mollusca, characterized by a unique larval stage (trochophore) and other shared features.

Radula

A toothed, chitinous ribbon used by mollusks for feeding, functioning like a rasp to scrape food particles.

Trochophore larvae

A type of larval stage found in many mollusks and some annelids, characterized by a free-swimming, ciliated structure.

Mantle

A significant body structure in mollusks that secretes the shell and covers the visceral mass.

Gastropoda

A class of mollusks that includes snails and slugs, known for their torsion process and diverse feeding habits.

Bivalvia

A class of mollusks that includes clams and mussels, characterized by a two-part shell and mostly filter-feeding lifestyle.

Cephalopoda

A highly developed class of mollusks, including squids and octopuses, recognized for their intelligence and advanced locomotion.

Torsion

A unique developmental process in gastropods where the visceral mass undergoes a 180-degree twisting during larval development.

Nephridia

Excretory organs in mollusks that help in the removal of waste materials and the regulation of body fluids.

Hemocoel

A body cavity found in mollusks, where blood circulates within a network of sinuses.

Open circulatory system

A type of circulatory system prevalent in most mollusks, where blood is not confined to vessels and fills body cavities.

What type of digestive system do Gastropoda possess?

Gastropoda typically have a complete digestive system, featuring specialized organs such as a radula for feeding.

How does the circulatory system function in Cephalopoda?

Cephalopoda have a closed circulatory system, which allows for efficient transport of oxygen and nutrients, enabling their active lifestyle.

What is the gas exchange system used by Bivalvia?

Bivalves use gills for gas exchange, filtering oxygen from water as it flows over the gills while feeding.

How do Aplacophora excrete waste?

Aplacophora utilize nephridia, specialized excretory organs, for the removal of waste materials and regulation of body fluids.

What type of nervous system is present in Gastropoda?

Gastropoda have a decentralized nervous system with a nerve ring and multiple ganglia, allowing for a range of responses and movement.

What skeletal structure is associated with the class Monoplacophora?

Monoplacophora possess a single, cap-like shell that provides protection and support to the soft body.

How is the muscular system organized in Cephalopoda?

Cephalopoda have a highly developed muscular system, allowing for complex movements such as jet propulsion and manipulation of their environment.

What reproductive strategy is typical for Bivalvia?

Bivalvia mostly reproduce sexually, with some species exhibiting external fertilization, where eggs and sperm are released into the water

What type of digestive system do Aplacophora possess?

Aplacophora have a simple digestive system that includes a mouth, esophagus, and a gut that extends throughout their body.

How do Aplacophora's feeding habits impact their digestive system?

Aplacophora primarily feed on small organic particles and detritus, utilizing their radula to scrape food off substrates.

What is the circulatory system structure in Aplacophora?

Aplacophora have an open circulatory system where blood bathes the internal organs in a hemocoel.

How do Polyplacophora perform gas exchange?

Polyplacophora utilize gills located within the mantle cavity for gas exchange, allowing oxygen to diffuse directly from water.

What is the excretory system of Bivalvia like?

Bivalvia have nephridia for excretion, which help to regulate body fluids and eliminate waste.

How do Scaphopoda's nervous systems differ from other mollusks?

Scaphopoda have a relatively simple nervous system, with a nerve ring and few ganglia, adapted for their burrowing lifestyle.

How does the skeletal structure function in Gastropoda?

Gastropoda possess a single shell that can be coiled or uncoiled, providing protection and support for their soft body.

What type of muscular organization do Bivalvia exhibit?

Bivalvia have a well-developed muscular system including adductor muscles that close their shell, allowing for protection.

How do Cephalopoda reproduce compared to other classes?

Cephalopoda primarily reproduce sexually with distinct mating practices, including male transfer of sperm via specialized arm structures.

What adaptations in the digestive system do Cephalopoda have?

Cephalopoda possess a complex digestive system with a beak and salivary glands that facilitate predation and digestion of prey.

How do the circulatory systems of Aplacophora and Monoplacophora compare?

Both Aplacophora and Monoplacophora have open circulatory systems, but Monoplacophora have more complex hemocoel structures.

What is the function of the radula in Gastropoda and Cephalopoda?

In Gastropoda, the radula is used for scraping food, while in Cephalopoda, it is often replaced by a beak for capturing prey.

How does the gas exchange system work in Scaphopoda?

Scaphopoda utilize their mantle for respiration, with gas exchange occurring through the mantle cavity and surrounding water.