Lecture 6: Phylum Nematoda and Introduction to Arthropods

Vocabulary practice flashcards covering the characteristics, classification, and key species of Phylum Nematoda and Phylum Arthropoda based on Lecture 6.

Bilateria

A clade of animals characterized by bilateral symmetry and three tissue layers.

Ecdysozoa

A group of animal phyla unified by molecular data and the possession of a three-layered cuticle or exoskeleton that is shed as the animal grows.

Ecdysis

The process of molting or shedding a hard covering, such as a cuticle or exoskeleton, to allow for growth.

Nematoda

Commonly known as roundworms or pin worms, this phylum contains approximately $25,000$ species of animals that lack a circulatory system.

Nematode Cuticle

An extracellular matrix acting as a barrier between the animal and environment, predominantly composed of extensively crosslinked collagen-like proteins.

Caenorhabditis elegans

A small free-living roundworm used as a model system in research; it was the first multi-cellular eukaryote to have its genome completely sequenced in $2002$.

WormBase

A comprehensive data resource for Caenorhabditis elegans biology and genomics.

Ascaris lumbricoides

A human hookworm referred to as a soil transmitted helminth; its eggs are notably resilient and can survive in formalin.

Dirofilaria immitis

The parasitic nematode that causes heartworm in dogs and cats, transmitted via mosquito bites.

Trichinosis

A disease caused by the parasitic nematode Trichinella spirosis, which forms encysted juveniles within muscle tissue.

Anisakis

Nematodes found in fish and shellfish that can cause allergies or infection in humans if consumed raw or inadequately processed.

Arthropoda

A phylum of Eumetazoans with over $1.2 \text{ million}$ discovered species and an estimated abundance of $10^{18}$ individuals.

Chitin

A polysaccharide polymer that is complexed with protein and calcium to form the rigid arthropod exoskeleton.

Chelicerata

An arthropod lineage that includes spiders and other arachnids.

Myriapoda

An arthropod lineage characterized by organisms such as centipedes.

Pancrustaceans

A major arthropod lineage that includes both Crustaceans and Hexapoda (insects).

Y-organ

The organ responsible for producing ecdysteroid hormone, which controls the molting process in arthropods.

Exuvium

The old cuticle or exoskeleton that is left behind after the process of ecdysis.