Animal Evolution & Diversity: Invertebrates Part II Lophotrochozoa and Ecdysozoa

Flashcards covering key vocabulary terms related to animal evolution and diversity, specifically focusing on invertebrates, including Lophotrochozoa, Ecdysozoa, Echinodermata, and Chordata.

Lophotrochozoa

All possess a lophophore, a distinct larval stage called a trochophore, or share molecular similarities with other members.

Lophophore

A feeding structure found in some Lophotrochozoa.

Trochophore

A distinct larval stage found in some Lophotrochozoa.

Platyhelminthes

Flatworms with no coelom; among the first animal predators; lack specialized respiratory or circulatory systems; digestive system is incomplete.

Rotifera

Possess a pseudocoelom and a ciliated crown (corona) to create water currents for feeding; have an alimentary canal with separate mouth and anus.

Bryozoa

Small colonial animals that possess a lophophore and a true coelom; important reef builders.

Brachiopoda

Small bottom-dwelling marine organisms with two shell halves that possess a lophophore and a true coelom.

Mollusca

Phylum with >100,000 living species, characterized by a soft body often protected by a shell; includes snails, slugs, oysters, mussels, squid, and octopus.

Mantle

Fold of skin over the visceral mass in mollusks; secretes a shell in species that form shells.

Radula

A unique tongue-like organ found in the mouth of mollusks.

Annelida

Phylum of segmented worms; exhibit advantages such as repetition of body components, minimized body distortion during muscle contraction, and segment specialization.

Ecdysozoa

Clade including nematodes and arthropods; all have a cuticle and undergo ecdysis (molting).

Ecdysis

The periodic molting of the cuticle in ecdysozoans.

Nematoda

Small pseudocoelomate worms covered by a tough collagen cuticle; reproduction is usually sexual with internal fertilization.

Arthropoda

Most successful phylum; characterized by an exoskeleton, jointed appendages, and extensive cephalization.

Tagmata

Functional units formed by fused body segments in arthropods (e.g., head or thorax).

Chelicerata

Arthropod subphylum containing spiders, scorpions, ticks, mites, and horseshoe crabs; have two tagmata: cephalothorax and abdomen.

Myriapoda

Arthropod subphylum including millipedes and centipedes.

Hexapoda

Arthropod subphylum comprising insects and relatives; have three tagmata (head, thorax, and abdomen).

Crustacea

Arthropod subphylum including crabs, lobsters, barnacles, and shrimp; possess two pairs of antennae.

Echinodermata

Phylum including sea stars, sea urchins, and sea cucumbers; display modified radial symmetry and have a water vascular system.

Autotomy

The ability to regenerate from a detached body part (limb) in echinoderms.

Chordata

Phylum including all vertebrates and some invertebrates; characterized by four critical innovations: notochord, dorsal hollow nerve cord, pharyngeal slits, and postanal tail.

Notochord

A flexible rod that lies between the digestive tract and the nerve cord in chordates.

Pharyngeal slits

Slits that open to the outside near the mouth in the pharyngeal region of chordates.

Cephalochordata

Subphylum of chordates including lancelets; all marine filter feeders, retain all four chordate characteristics as adults.

Urochordata

Subphylum of chordates including tunicates; larval stage displays all four chordate features, adult only displays pharyngeal slits.

Lophotrochozoa

Includes animals that possess a lophophore (feeding structure), a trochophore (distinct larval stage), or share molecular similarities. Key phyla include Platyhelminthes, Rotifera, Bryozoa, Brachiopoda, Mollusca, and Annelida.

Ecdysozoa

Includes animals that undergo ecdysis (molting). Key phyla include Nematoda and Arthropoda. Characterized by a cuticle.

Platyhelminthes (Lophotrochozoa)

Flatworms with no coelom; first animal predators; incomplete digestive system.

Rotifera (Lophotrochozoa)

Possess a pseudocoelom and a ciliated crown (corona) for feeding; have an alimentary canal.

Bryozoa (Lophotrochozoa)

Small colonial animals with a lophophore and a true coelom; reef builders.

Brachiopoda (Lophotrochozoa)

Bottom-dwelling marine organisms with two shell halves, a lophophore, and a true coelom.

Mollusca (Lophotrochozoa)

Soft-bodied animals often protected by a shell; includes snails, slugs, oysters, mussels, squid, and octopus. The mantle is a fold of skin over the visceral mass that