ANIMAL KINGDOM - Vocabulary Flashcards

A set of vocabulary-style flashcards covering key terms and concepts from the lecture notes on the Animal Kingdom, including levels of organisation, symmetry, germ layers, coelom, segmentation, and the major phyla and vertebrate classes.

Cellular level of organisation

Cells are arranged as loose aggregates with division of labour among cells and no true tissues (as in sponges).

Tissue level of organisation

Cells performing similar functions are organized into tissues.

Organ level of organisation

Tissues grouped to form organs, each specialised for a function.

Organ-system level of organisation

Organs work together as functional systems to perform physiological roles.

Asymmetry

Lack of any plane that divides the body into two identical halves (common in sponges).

Radial symmetry

Body can be divided into similar halves by any plane passing through the central axis.

Bilateral symmetry

Body can be divided into left and right halves by a single plane.

Diploblastic

Animals with two embryonic germ layers: ectoderm and endoderm; mesoglea lies between.

Triploblastic

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

Ectoderm

Outer germ layer giving rise to skin and nervous system components.

Endoderm

Inner germ layer forming the gut and associated organs.

Mesoderm

Middle germ layer giving rise to muscles, circulatory, and other systems.

Mesoglea

A gelatinous layer between the ectoderm and endoderm in diploblastic animals.

Coelom

Body cavity lined by mesoderm.

Coelomate

Animals possessing a true coelom.

Pseudocoelomate

Body cavity not completely lined by mesoderm; pseudocoelom is present.

Acoelomate

Animals that lack a body cavity.

Segmentation

Externally and internally divided into segments with serial repetition of organs.

Metamerism

Segmentation pattern seen in some annelids and other groups.

Notochord

A mesodermally derived rod-like structure on the dorsal side during embryonic development; characteristic of chordates; often replaced by vertebral column in adult.

Porifera (sponges)

Primarily marine, mostly asymmetrical animals with cellular level of organisation and a water canal system (ostia, spongocoel, osculum); choanocytes line canals; digestion intracellular; spicules/spongin skeleton; hermaphroditic; reproduction by fragmentation and internal fertilisation; indirect development via larva.

Choanocytes

Collar cells lining the spongocoel that help in feeding and water flow in sponges.

Coelenterata/Cnidaria

Aquatic, mostly marine, sessile or free-swimming, radial symmetry; diploblastic; tissue level of organisation; cnidocytes (cnidoblasts) with nematocysts; gastro-vascular cavity with a single opening.

Cnidoblasts (cnidocytes)

Stinging cells containing nematocysts used for prey capture, defence and anchorage in cnidarians.

Ctenophora

Sea walnuts or comb jellies; marine, radial symmetry, diploblastic; eight rows of ciliated comb plates for locomotion; bioluminescent; external fertilisation; sexual reproduction.

Platyhelminthes

Dorso-ventrally flattened, bilaterally symmetrical, triploblastic, acoelomate; organ-level organisation; often parasitic with hooks/suckers; flame cells for osmoregulation; Planaria show regeneration.

Aschelminthes (Nematoda)

Roundworms with a circular cross-section; pseudocoelomate; bilaterally symmetrical, triploblastic; complete alimentary canal; excretory pore; dioecious; direct or indirect development.

Annelida

Segmented worms with metameric segmentation; coelomate; closed circulatory system; nephridia; dorsal nerve cord; examples: Nereis, Pheretima; typically dioecious or monoecious; sexual reproduction.

Arthropoda

Largest animal phylum; segmented with jointed appendages; chitinous exoskeleton; open circulatory system; gills/book gills/book lungs or tracheal system; malpighian tubules; mostly dioecious; oviparous; direct or indirect development.

Mollusca

Soft-bodied animals often with a calcareous shell; mantle and mantle cavity with gills; head, muscular foot, visceral hump; radula for feeding; unsegmented.

Echinodermata

Marine animals with an internal calcareous endoskeleton; water vascular system; radial symmetry in adults (larvae are bilateral); coelomate; sexual reproduction; indirect development; no excretory system.

Hemichordata

Worm-like marine animals with stomochord; body divided into proboscis, collar and trunk; open circulatory system; gills; proboscis gland; indirect development; examples Balanoglossus and Saccoglossus.

Chordata

Animals with notochord, dorsal hollow nerve cord, pharyngeal gill slits and post-anal tail; bilateral, triploblastic, coelomate; vertebrates have a vertebral column.

Urochordata (Tunicata)

Subphylum of tunicates; notochord present only in the larval tail; marine and mostly sessile as adults.

Cephalochordata

Subphylum (lancelets) with notochord extending along the body throughout life; marine; retaining primitive chordate features.

Vertebrata

Subphylum of animals with a vertebral column replacing the notochord in the adult; includes fishes, amphibians, reptiles, birds and mammals; features like a ventral heart and paired appendages.

Cyclostomata

Jawless fishes (e.g., lampreys and hagfish); elongated body; 6–15 pairs of gill slits; circular, jawless mouth; cartilaginous cranium; marine but migrate to spawn in fresh water; indirect life cycle.

Chondrichthyes

Cartilaginous fishes with a cartilaginous endoskeleton; jaws; placoid scales; ventral mouth; persistent notochord; predaceous; must swim to stay afloat; examples Scoliodon, Pristis.

Osteichthyes

Bony fishes with a bony endoskeleton; gills covered by an operculum; four gills; swim bladder for buoyancy; two-chambered heart; mostly oviparous; external fertilisation; direct development; examples Exocoetus, Hippocampus, Labeo, Catla, Clarias.

Amphibia

Animals that live in both aquatic and terrestrial habitats; two pairs of limbs; moist skin; cloaca; respire via gills, lungs and skin; three-chambered heart; cold-blooded; external fertilisation; oviparous; often indirect development.

Reptilia

Dry, scaly skin; no external ears; limbs typically two pairs; heart usually three-chambered (four in crocodiles); poikilothermic; internal fertilisation; oviparous; direct development; examples Chelone, Testudo, Chameleon, Calotes, Crocodilus, Alligator, Naja, Bangarus, Vipera.

Aves

Birds with feathers, beaks, wings; hollow pneumatic bones and air sacs; dry skin; four-chambered heart; warm-blooded; oviparous; direct development; examples Corvus, Columba, Psittacula, Struthio, Pavo, Aptenodytes, Neophron.

Mammalia

Mammals characterized by mammary glands and hair; four-chambered heart; warm-blooded; mostly viviparous with direct development; internal fertilisation; examples Ornithorhynchus, Macropus, Pteropus, Camelus, Macaca, Rattus, Canis, Felis, Elephas, Equus, Delphinus, Balaenoptera, Panthera.