Nematodes and Phasmids Quiz

Annelida

• General Body Form: Bilaterally symmetrical, triploblastic, with a true coelom. Elongated and worm-like, divided into a presegmental region (prostomium), a region surrounding the mouth (peristomium), segmented body, and a posterior region (pygidium with anus).

Polychaetes

• Segmentation: Metamerically segmented, with true segmental hydrostats for locomotion. Septa divide the coelom into waterproof compartments. Fluid-filled septa provide support. Cephalization is present with a prostomium (head).

• Digestive System: Complete digestive tract with regional specialization.

• Nervous System: Ventral nerve cord, ganglia, and circular segmental connectives.

• Parapodia and Chaetae: Podium, chaetae arranged laterally in each segment, aiding in support and locomotion. Closed circulatory system with dorsal and ventral blood vessels.

• Reproduction: Trochophore larva; various reproductive strategies.

• Locomotion: Hydrostatic skeleton (support), muscles (longitudinal, circular, and oblique) allow for different movement patterns (crawl, rapid crawl, swimming, burrowing). Parapodia and chaetae enable power strokes, with oblique muscles moving them. Tube-dwellers have structural modifications – reduced parapodia, chaetae as anchors, slow peristaltic movement with chaetae, and head with specialized retractor muscles for feeding.

• Feeding and Digestion: Complete digestive tract; foregut (buccal tube, esophagus, muscular pharynx, jaws, glands, mucus and poison), midgut (esophagus, stomach, intestine with secretory cells), hindgut (anus). They are predators, suspension feeders, and some are symbiotic.

• Gas Exchange and Circulation: Parapodia (notopodium, neuropodium) increase surface area, facilitating gas exchange through body wall and/or gills. Closed circulatory systems with dorsal and ventral blood vessels; no heart, but movement of the body propels blood. Tube worms have capillary networks for transport.

• Excretion and Osmoregulation: Metanephridia arranged per segment, with an inner ciliated funnel and a duct (may include storage).

• Nervous System and Sense Organs: Dorsal cerebral ganglia, paired circumenteric connectives, ventral nerve cords with segmental ganglia, sensory receptors (touch, light) including eyes (pigment cup eye), ocelli, statocysts, and chemoreceptors.

• Reproduction: Asexual budding, hermaphroditic, or dioecious with external fertilization or spawning methods. Epitoky, a specialized reproductive individual, is also observed.

Crassiclitellata

• Characteristics: Lack parapodia, hermaphroditic.

• Digestive System: Foregut (buccal cavity, pharynx, esophagus, calciferous glands, crop, gizzard), midgut (intestine), and hindgut.

• Gas Exchange and Circulation: Diffusion, circumesophageal vessels (pseudohearts), dorsal and ventral blood vessels, subneural vessel.

• Nervous System and Sense Organs: Cerebral ganglion, segmental nerves, ventral nerve cord.

• Reproduction: Hermaphroditic with cross-fertilization. Female reproductive parts posterior to the male parts. Mucus, cocoon material, and albumin are involved. Mating involves alignment and production of mucus sheets and cocoons.

• Excretion and Osmoregulation: Metanephridia and protonephridia primarily involved in osmoregulation.

Hirudinea

• Body Plan: External annulation, no internal segmentation, thick dermal connective tissue filling spaces between muscle bands. Scavengers, predators, ectoparasites; anterior and posterior suckers.

• Movement: Anterior sucker attaches, body moves, and posterior sucker releases.

• Feeding and Digestion: Attach with anterior sucker, jaws cut host, pharynx pumps blood into gut. Crop and caeca store the blood meal, and gut bacteria assist in digestion. Water and salts are excreted during ingestion.

• Medical Importance: Reduce hematoma areas, promote bleeding, and reduce arthritis pain.

• Nervous System and Sense Organs: 2-10 dorsal eyes, sensory papillae; negatively phototactic, respond to vibrations, and warm temperatures.

• Reproduction: Hermaphroditic, sperm transfer via copulatory apparatus, clitellar area, cocoon receiving eggs, albuminous fluid, and nutrients. Direct development.

Mollusca

• General Characteristics: Second largest phylum, bilateral symmetry, triploblastic, coelomate (reduced), hemocoel, open circulatory system, mantle, heart in a pericardial chamber, muscular foot, radula, and complete gut specialization.

• Body Plan: Three regions (head, foot, visceral mass), mantle cavity housing respiratory surfaces (ctenidia), openings for gut, reproductive, and excretory systems.

• Shell: Calcareous exoskeleton.

• Digestion: Complete gut, with foregut, midgut, and hindgut. Radula, crystalline style, and other digestive accessory organs.

• Circulation and Gas Exchange: Open circulatory system, hemocoel, hemolymp, hemacyanin or hemoglobin, gills (ctenidia), countercurrent flow for gas exchange.

• Reproduction: Trochophore and/or veliger larvae, direct or indirect development.

• Feeding: Browsing/herbivorous, predatory, suspension, deposit feeders using jaws/radula/horny beak.

Bivalvia

• Characteristics: Two valves with a hinge, adductor muscles, no well-developed head, labial palps, enlarged mantle/cavity lines shell, foot for movement and digging, and ctenidia.

• Movement: Foot, burrowing, sessile forms.

• Feeding: Suspension (enlarged ctenidia), deposit feeding (large labial palps).

• Digestion: Complete gut, digestive glands, crystalline style (in some), with intracellular digestion.

• Circulation and Gas Exchange: Open circulatory system, reduced coelom, hemocoel, ctenidia, countercurrent exchange.

Gastropoda

• Characteristics: Asymmetrical, spirally coiled shell (except some). Head with eyes and tentacles, radula (usually), foot (with operculum), mantle rotated 90-180 degrees with respect to the foot (torsion).

• Movement: Foot, pedal glands, muscular contractions, some sedentary forms.

• Feeding: Radula, diverse feeding strategies, piercing, sucking, or rasping.

• Nervous System: Well-defined anterior ganglia forming a nerve ring, cerebral ganglia.

Heterobranchia

• Characteristics: Lack true ctenidia, simple gut, no crystalline style, short intestine, radula may be absent, reduced/absent shell, operculum (horny), head with eyes, 1-2 tentacles, hermaphroditic.

Cephalopoda

• Characteristics: Highly modified, shell reduced/lost (except nautilus), jet propulsion, closed circulatory system, large complex eyes, arms/tentacles, beak with radula, mantle cavity, muscular funnel, well-developed nervous system, benthic/pelagic, predators.

• Movement: Jet propulsion using siphon.

• Feeding: Hunting, injecting neurotoxin (octopus).

• Reproduction: Gonochoristic, male spermatophores, female oviduct, complex precopulatory behaviors, often with adult mortality after mating. Coloration, ink used for camouflage and communication.

Polyplacophora

• Characteristics: Flattened, 8 dorsal plates/valves, thick girdle, mantle cavity encircles foot, ctenidia, nephridia, no eyes or tentacles, radula.

Scaphopoda

• Characteristics: Shell (one piece, 2 openings), long mantle cavity, no ctenidia or eyes, radula, long proboscis, contractile tentacles.

Arthropoda

• Characteristics: Segmented, metameric repetition, tagmata (head, thorax, abdomen), thick cuticle exoskeleton (chitin + protein), jointed appendages, compound and simple eyes, reduced coelom (hemocoel), complete gut, nervous system (cerebral ganglia, ventral nerve cords), growth by ecdysis.

• Exoskeleton: Support, locomotion.

• Locomotion: Jointed appendages (protopod, telopod, epipods), peristalsis, no hydrostatic skeleton.

• Growth: Ecdysis (molting), controlled by hormones, staggered growth, stages between molts.

• Digestion: Foregut (mechanical), midgut (chemical digestion/absorption), hindgut (water absorption).

• Circulation and Gas Exchange: Open hemocoel, muscular heart, variations in vessels and gas exchange structures (gills, book lungs, tracheae).

• Excretion: Variety of structures (nephridia, antennal/maxillary glands, malpighian tubules, coxal glands).

• Nervous System: Cerebral ganglia, ventral ganglionated nerve cord.

• Sense Organs: Setae, hairs, bristles; mechanoreceptors, chemoreceptors, photoreceptors (simple and compound eyes).

Major Clade: Mandibulata and Subphylum Crustacea

• Characteristics: Three tagmata, appendages (biramous, uniramous), mandibles, two pairs of antennae, gills, nauplius larva.

• Body Plan: Fused thoracic segments, head (5 pairs of appendages, eyes), abdomen.

• Reproduction: Gonochoristic, hermaphroditic, various mating behaviors (courtship, combat), larval stages (nauplius, zoea, megalopa).

• Feeding: Filter feeding, active suspension feeding, and others.

Chelicerata

• Characteristics: Two tagmata, (prosoma, opisthosoma), no antennae, chelicerae, pedipalps, 4 pairs of walking legs, eyes (simple, often 4 pairs), book lungs/tracheae.

• Sensory Organs: Setae, trichobothria, pectines.

Hexapoda

• Characteristics: Three tagmata (head, thorax, abdomen), tracheal system, spiracles, tracheae, branching tracheoles.

Echinodermata

• Characteristics: Exclusively marine, triploblastic, deuterostomes, calcareous endoskeleton, pentaradial symmetry, water vascular system, mutable collagenous tissue.

• Body Wall: Epidermis covers body; dermis contains ossicles (plates), muscles, peritoneum, mutable connective tissues.

• Water Vascular System: Series of canals and tube feet.

• Nervous System: Decentralized nerve net, nerve ring, radial nerves.

Nematoda

• Characteristics: Triploblastic, bilateral, vermiform, unsegmented, pseudocoelomate, cylindrical body, cuticle, longitudinal muscles, cephalic and caudal sense organs, lack circulatory or respiratory systems, complete digestive system.

• Body Plan: Tube within a tube, pseudocoelom, cuticle (support, movement, secretion/excretion), longitudinal muscles (contraction against hydrostatic pressure), various sensory structures.

• Feeding and Digestion: Deposit/detritivores, carnivores, plant parasites; complete digestive tract with regions, buccal cavity, muscular pharynx, intestine.

• Osmoregulation: Renette cells, cuticle permeability.

• Nervous System and Sense Organs: Nerve ring, longitudinal nerves, various sensilla (amphids, phasmids, setae) involved in chemoreception, touch, and osmotic reception.

• Reproduction: Gonochoristic, sexual dimorphism, copulatory apparatus (in males). Various reproductive strategies (hermaphroditism, parthenogenesis).

Test your knowledge on nematodes and phasmids with this quiz! Explore fascinating questions about their reproductive strategies, developmental stages, and unique anatomical features. Ideal for biology enthusiasts and students alike!