chpt 3

Flashcards covering key vocabulary terms related to the lecture on chordates and their evolutionary processes.

Chordates

A phylum of animals that includes vertebrates, characterized by having a notochord, a dorsal nerve cord, and pharyngeal slits.

Gnathostomes

Jawed vertebrates, which evolved from jawless vertebrates and marked a significant evolutionary milestone.

Cyclostomes

Jawless vertebrates, including hagfish and lampreys, that are characterized by a lack of jaws and paired fins.

Mineralization

The process through which organisms develop mineralized structures, such as bones and teeth, typically involving calcium phosphate.

Conodonts

Extinct jawless vertebrates known for their unique mineralized teeth, once believed to be early vertebrates but now understood to be part of convergent evolution.

Notochord

A flexible rod that provides support in the embryos of all chordates; in vertebrates, it is typically replaced by the vertebral column.

Ostracoderms

An extinct group of armored jawless fish characterized by dermal bony structures and likely served as early vertebrates.

Anadromous

A term describing fish that migrate from the sea to freshwater to spawn, such as some lampreys.

Dermal denticles

Small, tooth-like structures found in the skin of some fish, providing protection and likely evolved into modern teeth.

Pharyngeal gill arches

Structures that in early vertebrates evolved to form the basis of the jaw mechanism; involved in respiration and feeding.