Phyla Hemichordata & Chordata Flashcards

Flashcards reviewing key vocabulary and concepts from the lecture on Hemichordates, Chordates, and Chondrichthyes.

Protochordates

Marine organisms that are suspension feeders. Includes acorn worms, sea squirts, and vertebrates as examples.

Hemichordates (Acorn Worms)

Marine animals with gill slits and a rudimentary notochord (not homologous with vertebrate notochords).

Stomochord

A conspicuous dorsal extension of the pharynx forming an anterior buccal tube.

Tornaria

A feeding planktonic larva formed during Hemichordate reproduction.

Phylum Chordata

Deuterostomes with gill slits (originally for filter feeding), dorsal hollow nerve cord, notochord, and post-anal tail.

Subphylum Urochordata

Tunicates, planktonic larvae, sessile adults, and suspension feeder specialists.

Subphylum Cephalochordata

Lancelets; Adults exhibit all chordate characteristics and use cilia-driven filter feeding.

Class Chondrichthyes

Cartilaginous fishes with well-developed jaws and highly developed sense organs.

Elasmobranchii

Sharks and rays, a subclass of Chondrichthyes.

Holocephali

Chimaeras, ratfish, and ghostfish; a subclass of Chondrichthyes.

Rajiformes

Skates, a type of Batoidea.

Torpediniformes

Electric rays, a type of Batoidea.

Rhinobatiformes

Guitarfishes and sawfishes, a type of Batoidea.

Myliobatiformes

Stingrays, a type of Batoidea.

Hexanchiformes/Chlamydoselachiformes

Cowsharks and Frill Sharks

Echinorhiniformes

Bramble Sharks

Squatiniformes

Angel Sharks

Pristiophoriformes

Sawsharks

Squaliformes

Dogfishes

Heterodontiformes

Horn Sharks

Orectolobiformes

Carpet Sharks

Lamniformes

Mackerel Sharks

Carcharhiniformes

Requiem/Ground Sharks

Placoid Scales

Small tooth-like structures that cover the skin of living shark species.

Hyostylic Jaw Suspension

A jaw suspension where the upper jaw is attached flexibly to the chondocranium in two locations allowing movement and a bigger bite.

Cranial Kinesis

Movement of parts of the head skeleton.

Chemoreception

Used to detect prey from a distance; sharks can detect odors as dilute as 1 part in 10 billion.

Lateral Line System

Used to detect vibrations from a distance.

Tapetum Lucidum

Reflects light back through the retina for vision at low light intensities.

Lateral Line System

Detects vibrations, orient the fish in water

Operculum

Gill cover Allows more water to be drawn in

Swim Bladder

A gas filled sac that helps the fish maintain buoyancy.

Ray Finned

Most fish are this type, and their fins are supported by bony structures called rays. Teleosts are the mos advanced form with symmetrical tails and mobile fins.

Lobe Finned

Their fins are long, fleshy, muscular, and supported by a central core of bones. Thought to be ancestors of amphibians. Examples: Coelacanth, Lungfish