The hard part of animals that are preserved in rock.

ex: exoskeletons, bones, shells, teeth, tusks...

1. Structure
2. Reproductive Body
3. Feeding Habit
4. Lifestyle
5. Time Period

A way to classify organisms that shows the evolutionary history of one group and of different groups.

-a relation of current organisms to others and to fossils.

A hypothesis of the lineages and their evolutionary relationships.

• A dichotomus branching pattern that ranges from oldest to newest.
• Based on derived characteristics
• Each group shares characteristics with the groups before it.

• Bilateral Symmetry
• Segmentation (VC)
• Coelum
• deuterostomes

1. Notochord
2. Pharyngeal Slits
3. Dorsal and Tubular Nerve Cord
4. Postanal Tail
5. Endostyle/Thyroid Gland

Slender rod from the mesoderm located dorsal to the coelum and ventral to the nerve cord.

- a core of cells and fluid surrounded by a sheath of fibrous connective tissue.

- laterally flexible, vertically tensile (scaffolding movement)

Replaces the notochord in adult mammals and boney fish.

(Remnant in the adult mammals is called the nucleus pulposus in the center of the intervertebral disks)

Slits in the wall of the pharynx.

Openings only (but devp for respiration in fish/amphibians)

• forms the ectoderm
• forms via invagination
• dorsal to the NC and gut
• hollow with a fluid-filled central canal

posterior elongation of the body past the anus.

- with muscle and NC

-everything involved in locomotion extends here.

Located on the floor of the pharynx.

Both involved in iodine metabolism.

1. Cephalochordata
2. Urochordata
3. Vertebrata

Cephalochordates, Urochordates and Hemichordates

Share some/all of the chordate characteristics

All 5 chordate characteristics.