Animal Kingdom - Phyla and Key Terms (Lecture Notes)

Vocabulary flashcards covering major phyla and chordate features from the notes.

Porifera

Sponges; marine, mostly asymmetrical; cellular level of organization; water canal system with ostia, spongocoel, and osculum; choanocytes line canals; intracellular digestion; skeleton of spicules or spongin; hermaphroditic; reproduce by fragmentation or formation of gametes; fertilization internal.

ostia

Minute pores in the sponge body wall through which water enters.

spongocoel

Central cavity inside a sponge where water collects before exiting.

osculum

Large opening through which water exits the sponge.

choanocytes

Collar cells lining the spongocoel and canals; facilitate feeding and water flow; enable intracellular digestion.

spicules

Calcareous or siliceous skeletal elements that provide structural support in sponges.

spongin

Protein fiber forming a flexible skeleton in some sponges.

hermaphrodite

Organism that possesses both male and female reproductive organs.

Porifera reproduction

Asexual reproduction by fragmentation; sexual reproduction with formation of gametes; fertilization can be internal.

Coelenterata (Cnidaria)

Aquatic, mostly marine, radially symmetric animals; diploblastic; tissue-level organization; gastro-vascular cavity with a single opening; cnidocytes with nematocysts; two body forms: polyp and medusa; digestion extracellular and intracellular.

cnidoblasts (cnidocytes)

Stinging cells containing nematocysts used for anchorage, defense, and prey capture.

nematocysts

Harpoon-like organelles inside cnidocytes that release toxins to capture prey.

polyp

Sessile, usually cylindrical cnidarian form.

medusa

Umbrella-shaped, free-swimming cnidarian form.

metagenesis

Alternation of generations; polyps produce medusae asexually and medusae form polyps sexually.

Cnidarians skeleton in corals

Some corals form a calcium carbonate skeleton.

cnidocytes

Specialized cells (cnidoblasts) with nematocysts for prey capture and defense.

Ctenophora

Sea walnuts/jellys; exclusively marine; diploblastic; radial symmetry; eight rows of ciliated comb plates (ctenes) for locomotion; digestion both extracellular and intracellular; bioluminescent; mostly dioecious; external fertilization; indirect development.

ctenes (comb plates)

Eight rows of ciliated plates used for locomotion in ctenophores.

bioluminescence

Emission of light by living organisms; well-marked in many ctenophores.

Pleurobrachia

Example genus of ctenophores.

Platyhelminthes

Flatworms; dorso-ventrally flattened; bilateral, triploblastic, and acoelomate; organ-level organization; flame cells for osmoregulation and excretion; often monoecious; internal fertilization; many endoparasites; Planaria shows regeneration.

flame cells

Excretory cells in flatworms involved in osmoregulation and excretion.

Aschelminthes

Roundworms; circular body cross-section; pseudocoelomate; organ-system level; bilaterally symmetrical; dioecious; complete alimentary canal; excretory pore; internal fertilization; direct or indirect development.

pseudocoelomate

Body cavity not fully lined by mesoderm (between endoderm and mesoderm).

Ascaris, Wuchereria, Ancylostoma

Examples of roundworms (Aschelminthes).

Annelida

Segmented, metamerically arranged, coelomate; bilateral; organ-system organization; closed circulatory system; nephridia; parapodia in some aquatic forms; double ventral nerve cord; most are dioecious (Nereis) or monoecious (earthworms, leeches).

parapodia

Lateral leg-like appendages in some polychaete annelids aiding in swimming.

Malpighian tubules

Excretory organs in arthropods for osmoregulation and waste excretion.

Arthropoda

Largest phylum; segmented body with chitinous exoskeleton; head, thorax, abdomen; jointed appendages; diverse respiratory systems (gills, book gills, book lungs, or tracheal system); open circulatory system; sensory organs; excretion via Malpighian tubules; mostly dioecious; internal fertilization; oviparous; development direct or indirect; examples Apis, Bombyx, Laccifer; vectors: Anopheles, Culex, Aedes; Locusta as pest.

exoskeleton (chitinous)

Hard external skeleton made of chitin in arthropods.

Malpighian tubules (arthropods)

Excretory organs in arthropods for waste removal and osmoregulation.

Mollusca

Second-largest phylum; aquatic or terrestrial; unsegmented; body with head, muscular foot, visceral mass; calcareous shell; mantle and mantle cavity; gills; radula; usually dioecious and oviparous; indirect development.

mantle cavity

Space between mantle and body hosting gills and excretory organs in molluscs.

radula

File-like rasping feeding organ in molluscs.

Echinodermata

Marine; endoskeleton of calcareous ossicles; adults radially symmetric, larvae bilateral; water vascular system for locomotion, feeding, and respiration; no excretory system; sexual reproduction with external fertilization; indirect development.

water vascular system

Hydraulic system unique to echinoderms used for locomotion and feeding.

Hemichordata

Worm-like marine animals; stomochord; open circulatory system; bilateral; triploblastic; coelomate; proboscis-collar-trunk body plan; external fertilization; examples Balanoglossus, Saccoglossus.

stomochord

Structure in hemichordates similar to a notochord; located in the proboscis region.

Chordata (Chordata)

Animals with notochord, dorsal hollow nerve cord, pharyngeal gill slits, and post-anal tail; bilateral; coelomate.

notochord

Flexible, rod-like support found in chordates; may be present in embryo and replaced by vertebral column in many adults.

dorsal hollow nerve cord

Nerve cord located dorsally and hollow; a defining chordate feature.

pharyngeal gill slits

Slits in the pharynx used for filter feeding or respiration in chordates.

post-anal tail

Tail extending beyond the posterior end (anus) in many chordates.

subphylum Vertebrata

Chordates with a backbone; includes divisions Agnatha and Gnathostomata; vertebrae replace notochord.

Agnatha

Jawless vertebrates; cyclostomes (e.g., lamprey and hagfish).

Cyclostomata

Class of jawless fishes with circular mouth; cartilaginous cranium and vertebral column; gill slits present; examples Petromyzon (lamprey), Myxine (hagfish).

Chondrichthyes

Cartilaginous fishes; persistent notochord; jaws; placoid scales; separate gill slits without an operculum; ventral mouth; must swim to avoid sinking; examples Scoliodon (shark), Pristis (sawfish).

Osteichthyes

Bony fishes; jawed vertebrates with a bone skeleton; typically possess a swim bladder.

Gnathostomata

Jawed vertebrates; includes fishes (Pisces) and Tetrapoda.

Pisces

Fishes; aquatic vertebrates; typically have fins and gills.

Tetrapoda

Vertebrates with four limbs; includes Amphibia, Reptilia, Aves, and Mammalia.

Amphibia

Cold-blooded vertebrates often with metamorphosis; eggs laid in water; both aquatic and terrestrial life stages.

Reptilia

Cold-blooded vertebrates with dry scaly skin; eggs often laid on land; includes snakes, lizards, turtles, crocodilians.

Aves

Birds; feathered, beaked vertebrates; lay hard eggs; characteristics adapted for flight.

Mammalia

Mammals; hair, mammary glands; typically viviparous with diverse forms.

Limulus

Limulus polyphemus; a living fossil horseshoe crab; example of Arthropoda.