Animal Kingdom Classification - Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering fundamental concepts, anatomical terms, and phyla/classes discussed in the Animal Kingdom lecture.

Animal Classification

Systematic arrangement of over a million described animal species based on common fundamental features.

Cellular Level of Organisation

Body plan where cells are loosely aggregated with minimal division of labour, as seen in sponges.

Tissue Level of Organisation

Grouping of similar cells into tissues performing common functions; present in coelenterates and ctenophores.

Organ Level of Organisation

Tissues grouped into organs specialised for particular functions; begins in Platyhelminthes.

Organ-System Level

Organs associated to form functional systems (digestive, circulatory, etc.); found from Annelida upwards.

Incomplete Digestive System

Digestive tract with a single opening serving as both mouth and anus.

Complete Digestive System

Digestive tract with two separate openings: mouth and anus.

Open Circulatory System

Blood pumped out of the heart bathes tissues directly; characteristic of arthropods and some molluscs.

Closed Circulatory System

Blood confined to vessels (arteries, veins, capillaries); present in annelids, chordates, and some molluscs.

Asymmetry

No plane divides the body into equal halves; typical of most sponges.

Radial Symmetry

Any plane through the central axis divides the body into similar halves; seen in coelenterates, ctenophores, adult echinoderms.

Bilateral Symmetry

Body divisible into mirror-image left and right halves only in one plane; characteristic of most higher animals.

Diploblastic

Animals with two embryonic germ layers (ectoderm and endoderm) separated by mesoglea.

Triploblastic

Animals with three germ layers: ectoderm, mesoderm, endoderm.

Coelom

Mesoderm-lined body cavity between body wall and gut wall.

Coelomate

Animal possessing a true mesoderm-lined coelom, e.g., annelids, chordates.

Pseudocoelomate

Animal with body cavity not completely lined by mesoderm, e.g., aschelminthes (nematodes).

Acoelomate

Animal lacking a body cavity, e.g., platyhelminthes.

Segmentation

Serial repetition of body units externally and internally; also called metamerism (e.g., earthworm).

Notochord

Dorsal mesodermal rod present during embryonic development in chordates.

Chordate

Animal possessing notochord, dorsal hollow nerve cord, and pharyngeal gill slits at some stage.

Non-Chordate

Animal lacking a notochord; includes phyla from Porifera to Echinodermata.

Metamerism

Phenomenon of segmented body organisation with repeated organs, as in annelids.

Choanocyte (Collar Cell)

Flagellated cell lining canals of sponges, generating water current and trapping food.

Cnidoblast (Cnidocyte)

Stinging cell of cnidarians containing nematocyst for defense and prey capture.

Comb Plate

Ciliated band arranged in eight rows on ctenophores, aiding locomotion.

Flame Cell

Excretory and osmoregulatory cell of platyhelminthes.

Malpighian Tubule

Excretory organ of terrestrial arthropods such as insects.

Radula

File-like rasping organ in molluscs used for feeding.

Placoid Scale

Tooth-like dermal scale of cartilaginous fishes.

Operculum

Bony gill cover in bony fishes (Osteichthyes).

Air (Swim) Bladder

Gas-filled sac in most bony fishes that regulates buoyancy.

Water Vascular System

Network of fluid-filled canals used for locomotion, food capture, and respiration in echinoderms.

Porifera

Phylum of multicellular, asymmetrical sponges with water canal system.

Spongocoel

Central cavity of a sponge into which water flows.

Coelenterata (Cnidaria)

Phylum of radially symmetrical aquatic animals bearing cnidoblasts, e.g., Hydra, jellyfish, corals.

Polyp

Sessile, cylindrical cnidarian body form (e.g., Hydra).

Medusa

Free-swimming, umbrella-shaped cnidarian form (e.g., Aurelia).

Metagenesis

Alternation between polyp and medusa forms in some cnidarians.

Ctenophora

Marine phylum of comb jellies exhibiting eight comb plates and bioluminescence.

Platyhelminthes

Phylum of dorsoventrally flattened acoelomate worms, many parasitic, e.g., tapeworms.

Aschelminthes (Nematoda)

Phylum of roundworms with pseudocoelom and complete alimentary canal.

Annelida

Segmented coelomate worms with closed circulation, e.g., earthworm, leech.

Parapodia

Paired lateral appendages of some polychaete annelids aiding swimming.

Arthropoda

Largest animal phylum with jointed appendages, chitinous exoskeleton, open circulation.

Mollusca

Second-largest phylum; soft-bodied animals with calcareous shell, mantle, and muscular foot.

Mantle Cavity

Space between mantle and visceral hump in molluscs containing gills.

Echinodermata

Marine phylum with spiny skin, calcareous ossicles, water vascular system, radial adult symmetry.

Hemichordata

Worm-like marine phylum with proboscis, collar, trunk, and stomochord.

Urochordata (Tunicata)

Subphylum of chordates where notochord is restricted to larval tail, e.g., Ascidia.

Cephalochordata

Subphylum with notochord extending from head to tail throughout life, e.g., Amphioxus.

Vertebrata

Subphylum of chordates with vertebral column replacing notochord in adults.

Cyclostomata

Jawless, cartilaginous, ectoparasitic vertebrates with circular sucking mouth, e.g., lamprey.

Chondrichthyes

Cartilaginous fishes with placoid scales, ventral mouth, no operculum; many viviparous.

Clasper

Copulatory organ on pelvic fins of male cartilaginous fishes.

Osteichthyes

Bony fishes with operculum, swim bladder, and cycloid or ctenoid scales.

Amphibia

Cold-blooded tetrapods living in water and on land; three-chambered heart; moist skin.

Cloaca

Common chamber for digestive, urinary, and reproductive tracts in amphibians, reptiles, birds.

Reptilia

Cold-blooded vertebrates with dry, cornified scales or scutes; mostly oviparous.

Aves

Warm-blooded vertebrates with feathers, wings, pneumatic bones, and four-chambered heart.

Mammalia

Warm-blooded vertebrates with hair, mammary glands, diaphragm, and usually viviparous.

Homoiothermous

Ability to maintain constant body temperature; characteristic of birds and mammals.

Poikilothermous

Body temperature varies with environment; seen in fishes, amphibians, reptiles.

Viviparous

Giving birth to live young after internal development.

Oviparous

Laying eggs that develop and hatch outside the mother’s body.

Indirect Development

Life cycle with a larval stage morphologically distinct from the adult.

Direct Development

Young ones resemble miniature adults, without a larval stage.