Bio HW 3

Porifera

Phylum that includes sponges.

Sessile

Describes organisms that remain fixed in one place and do not move.

Asymmetry

Type of symmetry demonstrated by Porifera.

Choanocyte

Specialized cell in sponges that uses flagella to create water currents for feeding.

Osculum

Large opening in a sponge that allows water to exit.

Spicule

Structural element found in sponges, providing support and protection.

Pore

Small openings in the sponge for water to enter.

Flagellum

Whip-like structure used by choanocytes to create water flow.

Cnidaria

Phylum that includes organisms like Hydra, jellyfish, and anemones.

Radial symmetry

Type of symmetry demonstrated by Hydra.

Tentacle

Arm-like structure in Hydra that is used for capturing prey.

Mouth

Opening in Hydra where food enters.

Gastrovascular cavity

Central digestive cavity in cnidarians where digestion occurs.

Epidermis

Outer layer of cells in Hydra.

Endodermis

Inner layer of cells lining the gastrovascular cavity in Hydra.

Mesoglea

Gelatinous substance between the epidermis and endodermis in cnidarians.

Cnidocytes

Specialized cells in cnidarians that contain stinging structures.

Nematocysts

Stinging organelles found within cnidocytes.

Platyhelminthes

Phylum that includes flatworms.

Turbellaria

Class of free-living flatworms.

Trematoda

Class of parasitic flatworms, commonly known as flukes.

Cestoda

Class of flatworms commonly known as tapeworms.

Parasitic

Describes organisms that live on or in a host and obtain nutrients at the host's expense.

Bilateral symmetry

Type of symmetry demonstrated by Platyhelminthes.

Scolex

The head region of a tapeworm, equipped with suckers or hooks for attachment.

Proglottid

Segment of a tapeworm that contains reproductive organs.

Cephalopod

Mollusks with a well-developed head and tentacles; literally means 'head-foot'.

Gastropod

Mollusks that are characterized by a single shell or no shell and a distinct head; literally means 'stomach-foot'.

Nematoda

Phylum that includes roundworms, commonly referred to as the roundworm phylum.

Ascaris lumbricoides

Most common parasitic roundworm infection in the US.

Arthropoda

Phylum meaning 'jointed legs', includes insects, arachnids, and crustaceans.

Crayfish

Crustacean that belongs to the subphylum Crustacea within Arthropoda.

Tympanum

Sound receptor found in insects, used for detecting sound.

Echinodermata

Phylum that includes sea stars, sea urchins, and sea cucumbers.

Madreporite

Sievelike structure in echinoderms that regulates water intake for the water vascular system.

Water vascular system

Network of water-filled canals in echinoderms used for locomotion and feeding.