Chordates and fishes

Chordates

Animals with a dorsal hollow nerve cord, notochord, pharyngeal gill slits, and typically a vertebral column.

Non-vertebrate chordates

Two groups of chordates without a backbone, specifically lancelets and tunicates.

Vertebrates

Chordates that have a backbone or vertebral column.

Lamprey feeding method

Lampreys eat by suction feeding on prey and rasping tissues.

Evolutionary traits separating vertebrates from lamprey

Jaws and paired fins.

Structure jaws evolved from

Cartilaginous gill arches.

Cartilaginous fish example

Sharks.

Trait shared by all cartilaginous fishes

Cartilage skeleton.

Structure protecting gills of ray-finned fishes

Operculum.

Regulation of buoyancy in ray-finned fishes

Swim bladder.

Importance of lobe-finned fishes

They are the evolutionary basis for four limbs.

Primitive lungs appearance

Primitive lungs appeared in early fish ancestors before swim bladders.

Gill structure for gas exchange

Lamellae increase surface area for gas exchange in fish.

Evolutionary traits from fish to land animals

Jaws → bony skeleton → lobed appendages → four limbs.

Amphibians need for moist environments

They lack amniotic eggs.

Group including 99% of all fish species

Ray-finned fishes.

Breathing method of some fish (e.g., sharks)

They breathe by constantly swimming.

Ancestors of amphibians

Lobe-finned fishes.

Adaptation for reproduction on land

Amniotic egg.

Three major groups of amphibians

Frogs/toads, salamanders, caecilians.