15 phylum chordata Flashcards
(chorda = “cord”)
* Bilateral symmetry with segmented body
* Triploblastic, eucoelomate
* Members show a more fundamental unity of organs and organ
systems than do other phyla
* The most adaptable of organic forms and able to occupy most
kinds of habitat
Phylum CHORDATA
The Five (5) Hallmarks of Chordates:
The notochord
Dorsal Tubular Nerve Cord
Pharyngeal Pouches and Slits
Endostyle / Thyroid Gland
Postanal Tail
A flexible, rodlike structure, extending the length of the
body; The presence of the notochord is an essential
characteristic that defines a chordate (even if it doesn’t
persist in the adult form of some early/primitive
chordates)
the notochord
A single and tube-like structure that is always located dorsal to the alimentary canal/digestive tract
Dorsal Tubular Nerve Cord
In vertebrates, the nerve cord passes through the neural arches of the vertebrae and the brain is surrounded by a
bony or cartilaginous cranium.
Openings that lead from the pharyngeal cavity to the
outside
Pharyngeal Pouches and Slits
in protochordates
for filter feeding
In aquatic chordates: become pharyngeal slits, and later
evolved into
internal gills
found in protochordates and lamprey larvae
endostyle
found in all chordates (adult lampreys and all vertebrates)
Thyroid gland
which function to regulate body temperate and metabolism
secrete iodine-based hormones
In protochordates, it is covered in musculature andprovides
motility for swimming
postanal tail
Heart present, with multiple chambers; blood containing
hemoglobin
This tube-like structure made of nervous tissue will eventually develop into the central nervous system.
Dorsal nerve cord
