What is Upland and lowland?
[[File:Factory Falls Wide View 3264px.jpg|thumb|300px|Typical upland river coming down from a height: the Factory Falls in the Pocono Mountains, [[Pennsylvania]]]][[File:Aerial of Jameson Island in the Big Muddy, view looking south.jpg|thumb|300px|Typical lowland river: the [[Big Muddy River|Big Muddy]], <br/>southern [[Illinois]]]] '''Upland''' and '''lowland''' are terms used in [[ecology]], [[physical geography]] and [[geology]]. They describe the relative height of land above [[sea level]].<ref>Pidwirny, Michael 2014. ''Glossary of Terms for physical geography. Kelowna, Canada: Planet Earth. {{ISBN|9780987702906}}</ref> Uplands have rivers and [[stream]]s which are fast-flowing, clear, and with plenty of oxygen. They drain high or mountainous country, and go down into broad [[plain]]s (where they become lowland rivers. Lowlands usually have warmer, slow-flowing waters carrying lots of [[sediment]] and with poor oxygen content. Upland rivers run fast and cut through rock ([[Colorado River]]). Lowland rivers [[meander]] slowly towards the coast ([[Mississippi River]]). They carry lots of [[soil]] and are a dark colour. Therefore the fish and other animals which live in the river are quite different according to the two stages or types of river. The terms also apply to large areas of land. Because mountain-building ([[orogeny]]) lifts up huge sections of the Earth, there are large areas which are well above sea level: the highlands. But on the trailing edge of a continent, the land is low.<ref>Pidwirny, Michael 2014. ''Understanding physical geography''. Kelowna, Canada: Planet Earth. {{ISBN|9780987702944}}</ref> So the Americas are (broadly speaking) high on the west (the [[American Cordillera]]) and low on the east ([[Amazon Basin|Amazon]], [[St. Lawrence River]] / [[Great Lakes]] basin, [[Mississippi]], and [[La Plata]]). This is a consequence of [[plate tectonics]], as the Americas have moved slowly west for over 100 million years. The [[Appalachians]] are a far older chain of ground-down mountains carri