Continent Europe and Asia together as a single continent, dubbed "Eurasia". In this model, the world is divided into six continents, with North America and South America considered separate continents. Geologists use the term "continent" in a different manner from geographers. In geology a continent is defined by continental crust: a platform of metamorphic and igneous rock, largely of granitic composition. Some geologists restrict the term 'continent' to portions of the crust built around stable Precambrian "shield", typically 1.5 to 3.8 billion years old, called a craton. The craton itself is an accretionary complex of ancient mobile belts (mountain belts) from
Largest organisms one of the largest and oldest clonal colonies on Earth. Among animals, the largest species are all marine mammals, specifically whales. The blue whale is believed to be the largest animal to have ever lived. The largest land animal classification is also dominated by mammals, with the African bush elephant being the most massive of these. The largest single-stem tree by wood volume and mass is the giant sequoia ("Sequoiadendron giganteum"), native to Sierra Nevada and California; it typically grows to a height of and in diameter. Multiple-stem trees such as banyan can be enormous. Thimmamma Marrimanu in India spreads