- Gnathostomata (/ˌnæθoʊˈstɒmətə/; from Ancient Greek: γνάθος (gnathos) ‘jaw’ + στόμα (stoma) ‘mouth’) are the jawed vertebrates. Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates, including humans. In addition to opposing jaws, living gnathostomes have true teeth (a characteristic which has subsequently been lost in some), paired appendages (pectoral and pelvic fins, arms, legs, wings, etc.), the elastomeric protein of elastin, and a horizontal semicircular canal of the inner ear, along with physiological and cellular anatomical characters such as the myelin sheaths of neurons, and an adaptive immune system that has the discrete lymphoid organs of spleen and thymus, and uses V(D)J recombination to create antigen recognition sites, rather than using genetic recombination in the variable lymphocyte receptor gene.
- Lake Itasca (Wikipedia)
Lake Itasca (/aɪˈtæskə/ eye-TASS-kə) is a small glacial lake, approximately 1.8 square miles (4.7 km2; 1,200 acres) in area. Located in southeastern Clearwater County, in the Headwaters area of north central Minnesota, it is notable for being the headwater of the Mississippi River. The lake is in Itasca State Park. It has an average depth of 20 to 35 feet (6.1 to 10.7 m) and is 1,475 feet (450 m) above sea level.