A digestive tract consisting of a tube running between a mouth and an anus; also called a complete digestive tract.
A member of a group of shelled cephalopods that were important marine predators for hundreds of millions of years until their extinction at the end of the Cretaceous period
An amoeba-like cell that moves by pseudopodia and is found in most animals. Depending on the species, it may digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, and change into other cell types.
A marine lophophorate with a shell divided into dorsal and ventral halves. (Blanks) are also called lamp shells.
A flagellated feeding cell found in sponges. Also called a collar cell, it has a collar-like ring that traps food particles around the base of its flagellum.
A specialized cell unique to the phylum Cnidaria; contains a capsule-like organelle housing a coiled thread that, when discharged, explodes outward and functions in prey capture or defense.
The transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva.
Typically a warm-water, tropical ecosystem dominated by the hard skeletal structures secreted primarily by the resident cnidarians. Some reefs also exist in cold, deep waters.
(1)The exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions. (2) A tough coat that covers the body of a nematode.
Member of a group of animal phyla identified as a clade by molecular evidence. Many ecdysozoans are molting animals.
A slow-moving or sessile marine deuterostome with a water vascular system and, in larvae, bilateral symmetry. Echinoderms include sea stars, brittle stars, sea urchins, feather stars, and sea cucumbers.
A hard encasement on the surface of an animal, such as the shell of a mollusk or the cuticle of an arthropod, that provides protection and points of attachment for muscles.
One of the three main parts of a mollusk; a muscular structure usually used for movement.
A central cavity with a single opening in the body of certain animals that functions in both the digestion and distribution of nutrients.
In invertebrates with an open circulatory system, the body fluid that bathes tissues.
An individual that functions as both male and female in sexual reproduction by producing both sperm and eggs.
A type of development in certain insects, such as grasshoppers, in which the young (called nymphs) resemble adults but are smaller and have different body proportions. The nymph goes through a series of molts, each time looking more like an adult, until it reaches full size.
An animal without a backbone. (Blank)s make up 95% of animal species.
One of a pair of jaw-like feeding appendages found in myriapods, hexapods, and crustaceans.
One of the three main parts of a mollusk; a fold of tissue that drapes over the mollusk's visceral mass and may secrete a shell.
A water-filled chamber that houses the gills, anus, and excretory pores of a mollusk.
The floating, flattened, mouth-down version of the cnidarian body plan. The alternate form is the polyp.
A process in ecdysozoans in which the exoskeleton is shed at intervals, allowing growth by the production of a larger exoskeleton.
In a cnidocyte of a cnidarian, a specialized capsule-like organelle containing a coiled thread that when discharged can penetrate the body wall of the prey.
A large opening in a sponge that connects the spongocoel to the environment.
Asexual reproduction in which females produce offspring from unfertilized eggs.
A free-living flatworm found in unpolluted ponds and streams.
An excretory system, such as the flame bulb system of flatworms, consisting of a network of tubules lacking internal openings.
A strap like rasping organ used by many mollusks during feeding.
The central cavity of a sponge.
An aquatic animal, such as a sponge, clam, or baleen whale, that feeds by sifting small food particles from the water.
One of numerous extensions of an echinoderm's water vascular system. (Blank blank) function in locomotion, feeding, and gas exchange.
One of the three main parts of a mollusk; the part containing most of the internal organs.