-Dorsal, hollow nerve cord - nervous system
-Notochord (usually present only in embryo) - support
-Pharyngeal pouches -paired structures in throat; may develop into gills
-Tail - extends beyond anus
About 96% of all chordate species belong in one subphylum:
Subphylum Vertebrata- Vertebrates
---Animals with a backbone or vertebral column (endoskeleton)
----Have spinal cord - dorsal, hollow nerve cord
----Front end of spinal cord develops a brain
Nonvertebrate Chordates -- 2 subphyla of chordates without backbones:
-Filter-feeders in ocean, adults are sessile
-Only larval tunicates have chordate characteristics, having a notochord during early development
-Small fishlike animals, that often live partly buried in the sand
-Adult lancelets have chordate characteristics
-Have definite head region
Timeline of Vertebrate Evolution
Check out: The History of Life at Berkeley.edu
|550 million years ago||Ordovician Period||
|400 million years ago||
"Age of Fishes"
|350 million years ago||
Carboniferous Period (and Permian)
"Age of Amphibians"
|240 million years ago||
"Age of Dinosaurs"
dinosaurs dominated the land for 150 million years - sauropods, theropods, etc..
|60 million years ago||
"Age of Mammals"
|340,000 years ago||Quaternary period||Humans appeard|