Invertebrates - Classifications and Characteristics

This set of flashcards covers key terms and definitions related to invertebrate classes and their characteristics as discussed in the lecture.

Annelids

A group of invertebrates with bodies composed of a series of fused rings, divided into three classes: Oligochaeta, Polychaeta, and Hirudinea.

Oligochaeta

A class of annelids that includes earthworms, characterized by a reduced head and the presence of chaetae.

Chaetae

Bristles made of chitin found on annelids, notably in class Oligochaeta, which aid in locomotion and anchorage.

Polychaeta

A class of annelids that are mostly marine segmented worms, characterized by a well-developed head and parapodia.

Hirudinea

A class of annelids that includes leeches, known for their flattened bodies and the presence of suckers for attachment.

Hirudin

A chemical secreted by leeches to prevent blood coagulation during feeding.

Ecdysozoa

The most species-rich animal group covered by a tough coat called a cuticle that is shed during the process of ecdysis.

Ecdysis

The process of molting or shedding the cuticle in ecdysozoans, such as nematodes and arthropods.

Arthropoda

A phylum that includes arthropods, characterized by a segmented body, exoskeleton made of chitin, and jointed appendages.

Chitin

A polysaccharide that makes up the exoskeleton of arthropods and chaetae in annelids.

Open circulatory system

A type of circulatory system in which a fluid called hemolymph circulates into spaces surrounding tissues and organs.

Chelicerata

A subphylum of arthropods that includes sea spiders, horseshoe crabs, and arachnids, characterized by claw-like feeding appendages called chelicerae.

Myriapoda

A subphylum of arthropods that includes millipedes and centipedes, characterized by having many body segments and jaw-like mandibles.

Insecta

The class of arthropods that includes insects, which are often highly diverse and abundant in ecosystems.

Crustacea

A subphylum of arthropods that includes crabs, lobsters, and shrimps, often having branched appendages that are specialized for feeding and locomotion.

Echinoderm

A group of marine invertebrates known for their radial symmetry and unique water vascular system.

Water vascular system

A specialized hydraulic system in echinoderms used for locomotion, feeding, and gas exchange.

Chordata

A phylum that includes vertebrates and two subphyla of invertebrates, characterized by shared embryonic features with echinoderms.