Vertebrates: Fish and Amphibians

Comprehensive vocabulary flashcards covering the characteristics, classifications, and biological processes of chordates, fish, and amphibians based on lecture notes.

Vertebrates

A subgroup of the phylum Chordata that possesses a backbone or vertebral column made of cartilage or bone.

Chordata

A phylum that includes vertebrates as well as invertebrates such as tunicates and lancelets.

Notochord

A stiff but flexible rod that extends the length of the body for muscle attachment; in vertebrates, it develops into intervertebral disks.

Nerve cord

A structure located dorsally above the notochord that develops into the brain and the spinal cord.

Pharyngeal gill slits

Openings in the space behind the mouth that develop into gills or disappear in adult air-breathing animals.

Post-anal tail

An extension of the body past the anus that appears in chordate embryos and may be modified or disappear in adult forms.

Hagfishes

Jawless chordates that lack a true backbone, possess a rudimentary braincase, and secrete massive quantities of slime for defense.

Tetrapods

Vertebrates that possess 4 limbs of any type.

Ectothermic

A characteristic of most fish and amphibians meaning they cannot control their own internal body temperature and must absorb external heat.

Lampreys

Jawless fish with suckerlike mouths and rasping teeth, many of which are parasitic and suck blood from other fish.

Cartilaginous fish

A group including sharks, rays, and skates that have a skeleton made of cartilage and a two-chambered heart.

Mermaid’s purses

Egg cases laid by certain species of cartilaginous fish.

Swim bladder

An internal air sac in bony fish used to control buoyancy.

Lobe-finned fish

A group of bony fish with paired, fleshy fins that resemble limbs, considered ancestors to tetrapods.

Ray-finned fish

A diverse group of bony fish with paired fins characterized by spiny endings.

Aestivation

A state of hibernation during the summer involving a reduced metabolic state where breathing, body temperature, and heart rate are lowered.

Coelocanth

A carnivorous "living fossil" fish thought to be extinct until 1938, characterized by live-bearing pups and deep-ocean habitation.

Operculum

A gill flap that protects the gills and aids in drawing water through them.

Lateral line

A sensory structure in ray-finned fish that detects vibrations in the water.

Countercurrent exchange

A respiratory process in gills where blood moves in the opposite direction of water to ensure oxygen diffuses into the bloodstream.

Tiktaalik roseae

A fossil found in 2006 considered an evolutionary link between fish and tetrapods, featuring wrist bones and a swiveling head.

Order Urodelia

The order of Class Amphibia that includes newts and salamanders.

Order Anura

The order of Class Amphibia that includes frogs and toads.

Order Gymnophiona

The order of Class Amphibia consisting of caecilians, which are worm-like burrowing amphibians.

Amplexus

The clasping position assumed by a male amphibian during copulation.

Thanatosis

A defensive behavior in amphibians described as playing dead.

Mimicry

An amphibian defense mechanism where an organism copies the appearance of a poisonous species.

Ethylene glycol

A chemical antifreeze that fills the cells of wood frogs, allowing them to survive freezing temperatures while 60% of their extracellular fluid turns to ice.