Survey of the Animal Kingdom - Phyla Platyhelminthes and Mollusca

Flashcards covering key concepts from the lecture on the animal kingdom, particularly focusing on phyla Platyhelminthes and Mollusca.

Platyhelminthes

A phylum comprising flatworms which are solid, unsegmented, bilaterally symmetrical and typically have no body cavity.

Mollusca

A phylum that includes snails, clams, and octopuses; characterized by a soft body that is often divided into three parts: head-foot, visceral mass, and mantle.

Acoelomate

An organism that lacks a coelomic cavity; flatworms are classified as acoelomates.

Coelomate

An organism with a true coelom or body cavity lined with mesoderm; mollusks fall into this category.

Protostome

A group of animals where the first opening during embryonic development becomes the mouth; includes phyla like Platyhelminthes and Mollusca.

Lophotrochozoa

A clade of protostomes that includes several phyla such as Platyhelminthes and Mollusca, characterized by having lophophores or trochophore larvae.

Trematoda

A subgroup of flatworms, commonly known as flukes, which are primarily parasitic.

Scolex

The anterior end of a tapeworm, equipped with hooks or suckers to attach to the host's intestinal wall.

Radula

A unique rasping tongue-like organ found in many mollusks, used for feeding.

Gastropoda

A class of mollusks that includes snails and slugs, often characterized by a single coiled shell.

Bivalvia

A class of mollusks that have a two-part shell, includes clams and oysters.

Cephalopoda

A class of mollusks such as squids and octopuses, known for their tentacles and advanced nervous systems.

Hermaphroditic

Referring to an organism that has both male and female reproductive organs.

Ecdysis

The process of molting or shedding the outer cuticle or exoskeleton, which is common in certain protostomes.

Parasitic

Describing organisms that live on or in a host organism, deriving nutrients at the host's expense.

Mesoderm

One of the three germ layers in an embryo; in acoelomates, it is a solid mass without a coelomic cavity.