Animal Unit Flashcards
Invertebrates
An animal lacking a backbone and internal skeleton.
Multicellular
Consisting of many cells.
Eukaryotic
A cell with a definitive nucleus
Phylogeny
The evolutionary or ancestral history of organisms.
Deuterostome
A division of the animal kingdom which includes the phyla Echinodermata, Chaetognatha, Hemichordata, and Chordata.
Blastula
A hollow sphere of cells characteristic of the early metazoan embryo.
Blastopore
The opening of the archenteron.
Pinacocytes
A flattened polygonal cell occurring in the dermal epithelium of sponges, and lining the exhalant canals.
Amoebocytes
One of the wandering ameboid cells in the tissues and fluids of many invertebrates that function in assimilation and excretion.
Platyhelminthes
A phylum of invertebrates composed of bilaterally symmetrical, nonsegmented, dorsoventrally flattened worms characterized by lack of coelom, anus, circulatory and respiratory systems, and skeleton.
Trematode
A loose grouping of acoelomate, parasitic flatworms of the phylum Platyhelminthes; they exhibit cephalization, bilateral symmetry, and well-developed holdfast structures.
Pharynx
A chamber at the oral end of the vertebrate alimentary canal, leading to the esophagus.
Scolex
The head of certain tapeworms, typically having a muscular pad with hooks, and two pairs of lateral suckers.
Proglottids
One of the segments of a tapeworm.
Nephridia
Any of various paired excretory structures present in the Platyhelminthes, Rotifera, Rhynchocoela, Acanthocephala, Priapuloidea, Entoprocta, Gastrotricha, Kinorhyncha, Cephalochorda, and some Archiannelida and Polychaeta.
Hydrostatic skeleton
Water contained within the coelenteron and serving a skeletal function in most cnidarian polyps.
Gastropoda
A large, morphologically diverse class of the phylum Mollusca, containing the snails, slugs, limpets, and conchs.
Dioecious
Having the male and female reproductive organs on different individuals. Also known as dioic.
Hemocyanin
A blue respiratory pigment found only in mollusks and in arthropods other than insects.
Chromatophores
A type of pigment cell found in the integument and certain deeper tissues of lower animals that contains color granules capable of being dispersed and concentrated.
Echinodermata
A phylum of exclusively marine coelomate animals distinguished from all others by an internal skeleton composed of calcite plates, and a water-vascular system to serve the needs of locomotion, respiration, nutrition, or perception.
Ophiuroidea
The brittle stars, a subclass of the Asterozoa in which the arms are usually clearly demarcated from the central disk and perform whiplike locomotor movements.
Ophiuroidea
The brittle stars, a subclass of the Asterozoa in which the arms are usually clearly demarcated from the central disk and perform whiplike locomotor movements.
Pedicellaria
In echinoids and starfishes, any of various small grasping organs in the form of a beak carried on a stalk.
