Zoology Exam 3

Hexapoda

A subphylum of Arthropoda characterized by organisms with six legs and three body regions (head, thorax, abdomen).

Entognatha

A class of Hexapoda with mouthparts that are enclosed within the head capsule; examples include springtails.

Insecta

The most diverse class of the Hexapoda, characterized by external mouthparts and usually two pairs of wings.

Chitin

A carbohydrate that forms the exoskeleton of insects, providing rigidity and waterproofing.

Metamorphosis

A biological process through which an insect transforms its body structure during developmental stages.

Holometabolous metamorphosis

A type of metamorphosis where the organism undergoes a dramatic transformation from larva to pupa to adult.

Exoskeleton

An external skeleton that supports and protects an organism's body; in insects, primarily made of chitin.

Tracheal system

A network of tubes in insects that facilitates gas exchange, bringing oxygen directly to tissues.

Pentaradial symmetry

A body plan often seen in echinoderms, where any one-fifth of the body has similar structures to the others.

Echinodermata

A phylum of marine animals, characterized by a spiny endoskeleton and a unique water vascular system.

Asteroidea

A class of echinoderms that includes sea stars, characterized by a central disc and tapering arms.

Ophiuroidea

A class of echinoderms known as brittle stars, distinguished by their slender arms and lack of suckers on tube feet.

Ecosystem

A community of living organisms and their interaction with the nonliving environment.

Food web

A complex network of feeding relationships among organisms in an ecosystem.

Biogeochemical cycles

Natural cycles that involve the movement of elements and compounds through living (biotic) and nonliving (abiotic) components.

Cormorant

A type of bird that is often discussed in ecological studies due to its sensitivity to environmental changes.

Ectothermic

Organisms that rely on external sources of heat to regulate their body temperature.

Anadromous

A term used for fish that migrate from saltwater to freshwater to spawn.

Countercurrent exchange

A mechanism in fish gills allowing for efficient oxygen extraction from water.

Vitellogenin

A protein produced by female fish to form egg yolk; its presence in males can indicate intersex conditions.