Introduction to Cnidaria and Platyhelminthes

These flashcards cover key vocabulary and concepts related to Cnidaria and Platyhelminthes, including specific terms and definitions relevant to the biology of these organisms.

Phylum Cnidaria

A phylum of animals characterized by their two-part life cycle, which includes a sessile polyp and a free-swimming medusa.

Cnidoblasts

Specialized stinging cells found in Cnidaria, containing nematocysts that can harpoon and poison prey.

Mesoglea

The gelatinous substance found between the ectoderm and endoderm layers in Cnidarians, providing structural support.

Gastrovascular cavity

A central cavity in some animals, serving both digestive and circulatory functions.

Class Hydrozoa

A class within Cnidaria that includes organisms like Hydra and Obelia, often exhibiting both polyp and medusa forms.

Hydra

A genus of freshwater Cnidarians known for their ability to reproduce asexually through budding.

Class Scyphozoa

A class of Cnidarians primarily represented by jellyfish, which mainly exist in the medusa stage.

Anthozoa

A class of Cnidarians that includes corals and sea anemones, which are attached to substrates and do not have a medusa stage.

Phylum Platyhelminthes

A phylum of flatworms, characterized by their bilateral symmetry and lack of a coelom.

Acoelomate

An organism that does not possess a coelomic cavity, such as flatworms.

Budding

A form of asexual reproduction in which a new organism develops from an outgrowth on the parent.

Sexual reproduction

The process by which organisms create offspring through the fusion of sperm and eggs.

Bilaterally symmetrical

Having a body plan that can be divided into two mirror-image halves along a single plane.

Rostral end

The head end of a bilaterally symmetrical organism.

Caudal end

The tail end of a bilaterally symmetrical organism.

Tentacles

Extensions from the body of a Cnidarian that contain cnidoblasts and are used for capturing prey.