Zoology – Invertebrate & Vertebrate Vocabulary

100 English vocabulary flashcards covering key terms from the Invertebrate & Vertebrate Zoology lecture notes.

Zoology

Branch of biology devoted to the scientific study of animals, including their structure, physiology, behavior, and classification.

Systematics

The scientific discipline concerned with classifying organisms and determining their evolutionary relationships.

Kingdom

Highest obligatory taxonomic rank in traditional classification; Animalia is the kingdom for all animals.

Phylum

Major taxonomic category below kingdom grouping organisms that share a basic body plan; e.g., Chordata, Arthropoda.

Binomial Nomenclature

Linnaean system assigning every species a two-word Latin name: Genus (capitalized) + species (lowercase).

Protozoa

Unicellular eukaryotic organisms considered the simplest animals; feed, move, and reproduce as single cells.

Sarcodina

Protozoan class characterized by locomotion via pseudopodia; includes Amoeba species.

Mastigophora

Protozoan class whose members move with one or more flagella; also called Flagellata.

Sporozoa

Protozoan class of non-motile parasites that reproduce by spore formation; includes Plasmodium.

Ciliophora

Protozoan class possessing cilia for locomotion or feeding; example organism Paramecium.

Amoeba

Free-living sarcodine protozoan with changing shape and pseudopodia used for movement and phagocytosis.

Entamoeba histolytica

Pathogenic amoeba inhabiting human large intestine; causes amoebic dysentery.

Trypanosoma

Flagellated protozoan genus causing African sleeping sickness; transmitted by tsetse flies.

Plasmodium

Sporozoan genus responsible for malaria in humans; alternates between Anopheles mosquitoes and vertebrate host.

Paramecium

Free-living ciliate protozoan with slipper shape, oral groove, macro- and micronuclei.

Trophozoite

Active, feeding stage in a protozoan life cycle before reproduction or encystment.

Cyst

Dormant, resistant stage of protozoa enclosed in a protective wall for survival outside host.

Gametocyte

Protozoan stage that differentiates into gametes for sexual reproduction.

Flagellum

Long whip-like locomotory organelle composed of microtubules; propels Mastigophora and other cells.

Cilium

Short, numerous hair-like projection producing locomotion or water currents in Ciliophora.

Pseudopodium

Temporary cytoplasmic extension in sarcodines used for movement and engulfing food.

Macronucleus

Larger nucleus in ciliates controlling metabolic and developmental functions.

Micronucleus

Smaller reproductive nucleus in ciliates responsible for genetic exchange during conjugation.

Metazoa

Multicellular animals with specialized tissues, organs, and usually sexual reproduction.

Diploblastic

Having two primary germ layers—ectoderm and endoderm—during development; characteristic of Cnidaria.

Triploblastic

Having three embryonic germ layers—ectoderm, mesoderm, endoderm; found in most animal phyla.

Mesoglea

Non-cellular, gelatinous layer between epidermis and gastrodermis of diploblastic animals like cnidarians.

Porifera

Phylum of sponges; sessile, porous, filter-feeding animals with choanocyte-lined canals.

Spongocoel

Central cavity within many sponges through which water flows before exiting the osculum.

Osculum

Large excurrent opening at the top of a sponge allowing filtered water to leave.

Choanocyte

Collar cell lining sponge canals; flagella drive water current and trap food particles.

Pinacocyte

Flat epidermal-like cell forming the outer pinacoderm layer of a sponge.

Amoebocyte

Mobile sponge cell within mesohyl that digests food, forms spicules, and can differentiate.

Spicule

Calcareous or siliceous skeletal element supporting sponge body.

Asconoid

Simplest sponge body type with a single tubular spongocoel lined by choanocytes.

Syconoid

Intermediate sponge form with folded body wall creating radial flagellated canals.

Leuconoid

Most complex sponge architecture with a network of small flagellated chambers and no central cavity.

Filter Feeder

Organism that strains suspended matter and food from water; characteristic feeding of sponges.

Gemmule

Asexual, overwintering internal bud of freshwater sponges containing archaeocytes.

Cnidaria

Phylum of radially symmetrical aquatic animals possessing cnidocytes; includes jellyfish and corals.

Nematocyst

Stinging capsule inside cnidocytes used for prey capture and defense in cnidarians.

Polyp

Sessile, tubular cnidarian body form with mouth and tentacles oriented upward.

Medusa

Free-swimming, bell-shaped cnidarian stage with downward-facing mouth; typical of jellyfish.

Hydra

Freshwater hydrozoan polyp capable of asexual budding and simple regeneration.

Gastrovascular Cavity

Central digestive compartment with single opening serving as mouth and anus in cnidarians and flatworms.

Mesoglea

(Cnidarian context) Jelly-like acellular layer between epidermis and gastrodermis.

Planaria

Free-living freshwater flatworm (Turbellaria) noted for high regenerative ability.

Flame Cell

Ciliated excretory cell (protonephridium) of flatworms that propels waste-laden fluid.

Protonephridium

Network of tubules ending in flame cells responsible for osmoregulation in acoelomates.

Nerve Net

Diffuse network of interconnected nerve cells typical of cnidarians and simple worms.

Platyhelminthes

Phylum of dorsoventrally flattened acoelomate worms; includes planarians, flukes, tapeworms.

Bilateral Symmetry

Body plan with left and right halves that are mirror images; first appears in flatworms.

Acoelomate

Animal lacking a body cavity between gut and body wall; e.g., flatworms.

Nematoda

Phylum of unsegmented roundworms with a pseudocoelom and complete digestive tract.

Pseudocoelom

Fluid-filled body cavity not entirely lined by mesoderm; characteristic of nematodes.

Cuticle

Tough, flexible, non-cellular outer layer secreted by epidermis of nematodes and arthropods.

Ascaris lumbricoides

Large human intestinal roundworm; causes ascariasis.

Coelom

True fluid-filled body cavity completely lined by mesodermal peritoneum.

Annelida

Phylum of segmented worms with true coelom and metameric organization.

Metamerism

Serial repetition of similar body segments along the anterior–posterior axis, as in annelids.

Setae

Chitinous bristles on annelid segments providing traction for locomotion.

Nephridium

Segmental excretory organ of annelids that removes metabolic wastes from coelomic fluid.

Polychaeta

Class of mainly marine annelids with many setae and parapodia; e.g., Nereis.

Hirudinea

Class of annelids comprising leeches; lack setae and possess suckers.

Oligochaeta

Class of annelids with few setae per segment; includes earthworms.

Nereis

Marine polychaete (ragworm) with parapodia and acicula; often used in studies of segmentation.

Mollusca

Large phylum of soft-bodied animals typically with mantle, muscular foot, and visceral mass.

Mantle

Molluscan body wall fold that secretes the shell and forms mantle cavity.

Radula

Chitinous rasping tongue-like ribbon bearing rows of teeth in most molluscs.

Hemocoel

Primary body cavity of molluscs and arthropods containing circulatory fluid.

Bivalvia

Mollusc class with two-part hinged shell and laterally compressed body; clams, oysters.

Gastropoda

Largest mollusc class; asymmetrical body and helical shell in many; snails, slugs.

Cephalopoda

Mollusc class of active marine predators with tentacles and closed circulation; squids, octopuses.

Echinodermata

Phylum of deuterostome marine animals with pentaradial symmetry and calcareous endoskeleton.

Water Vascular System

Network of fluid-filled canals in echinoderms powering locomotory tube feet.

Tube Foot

Hydraulic appendage of echinoderms used for locomotion, feeding, and respiration.

Madreporite

Porous sieve plate on echinoderm surface that admits seawater to the water vascular system.

Pedicellariae

Tiny pincer-like defensive or cleaning appendages on echinoid and asteroid surfaces.

Sea Urchin

Globular echinoderm with movable spines and Aristotle’s lantern for grazing.

Chordata

Animal phylum characterized by notochord, dorsal hollow nerve cord, pharyngeal slits, and post-anal tail.

Notochord

Flexible, rod-like supportive structure in chordate embryos and some adults.

Dorsal Hollow Nerve Cord

Tubular nervous system structure running above the notochord in chordates; develops into brain and spinal cord.

Pharyngeal Gill Slits

Series of openings in pharyngeal region of chordates functioning in feeding or respiration.

Urochordata

Subphylum of sessile marine chordates (tunicates) with notochord and nerve cord only in larval stage.

Tunic

Cellulose-containing outer covering of adult tunicates.

Cephalochordata

Subphylum of small marine chordates (lancelets) retaining notochord and gill slits throughout life.

Amphioxus

Common name for Branchiostoma (lancelet); model cephalochordate exhibiting basic chordate traits.

Vertebra

Bony or cartilaginous segment forming the vertebral column of vertebrates.

Agnatha

Jawless vertebrate superclass including lampreys and hagfish.

Cyclostomata

Class of living agnathans distinguished by circular suctorial mouth and lack of paired fins.

Gnathostomata

Jawed vertebrate superclass encompassing fishes, amphibians, reptiles, birds, and mammals.

Cartilaginous Fish (Chondrichthyes)

Class of jawed fishes with skeletons of cartilage; sharks, rays, skates.

Osteichthyes

Class of bony fishes with ossified skeleton and swim bladder; largest group of vertebrates.

Amphibia

Class of vertebrates with dual life cycle, moist glandular skin, and three-chambered heart; frogs, salamanders.

Tympanic Membrane

External eardrum of amphibians and reptiles transmitting sound to middle ear.

Reptilia

Class of amniote vertebrates with keratinized scales and mostly three-chambered heart; snakes, turtles.

Amniotic Egg

Reptile, bird, and monotreme egg containing amnion, chorion, allantois, and yolk sac for terrestrial development.

Aves

Class of feathered, bipedal, warm-blooded vertebrates adapted for flight; birds.

Air Sacs

Thin-walled extensions of bird lungs providing unidirectional airflow and reducing body mass.

Mammalia

Class of endothermic vertebrates with hair, mammary glands producing milk, and differentiated teeth.