NeanderthalNeanderthals (niˈændə(r)ˌtɑːl,neɪ-,-ˌθɑːl; Homo neanderthalensis or H. sapiens neanderthalensis), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. The reasons for Neanderthal extinction are disputed. Theories for their extinction include demographic factors such as small population size and inbreeding, competitive replacement, interbreeding and assimilation with modern humans, climate change, disease, or a combination of these factors.
Population bottleneckA population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violence or intentional culling, and human population planning. Such events can reduce the variation in the gene pool of a population; thereafter, a smaller population, with a smaller genetic diversity, remains to pass on genes to future generations of offspring through sexual reproduction.
Archaic humansA number of varieties of Homo are grouped into the broad category of archaic humans in the period that precedes and is contemporary to the emergence of the earliest early modern humans (Homo sapiens) around 300 ka. Among the earliest remains of H. sapiens are Omo-Kibish I (Omo I) from southern Ethiopia ( 195 or 233 ka), the remains from Jebel Irhoud in Morocco (about 315 ka) and Florisbad in South Africa (259 ka). The term typically includes H. antecessor, H. bodoensis, Denisovans (H. denisova), H.
Types of volcanic eruptionsSeveral types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs, and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.
HominidaeThe Hominidae (hɒˈmɪnᵻdiː), whose members are known as the great apes or hominids (ˈhɒmᵻnɪdz), are a taxonomic family of primates that includes eight extant species in four genera: Pongo (the Bornean, Sumatran and Tapanuli orangutan); Gorilla (the eastern and western gorilla); Pan (the chimpanzee and the bonobo); and Homo, of which only modern humans (Homo sapiens) remain. Several revisions in classifying the great apes have caused the use of the term hominid to vary over time.
Human evolutionHuman evolution is the evolutionary process within the history of primates that led to the emergence of Homo sapiens as a distinct species of the hominid family, which includes all the great apes. This process involved the gradual development of traits such as human bipedalism, dexterity and complex language, as well as interbreeding with other hominins (a tribe of the African hominid subfamily), indicating that human evolution was not linear but weblike.
VolcanoA volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates.
SumatraSumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 475,807.63 km2 (182,812 mi.2), including adjacent islands such as the Simeulue, Nias, Mentawai, Enggano, Riau Islands, Bangka Belitung and Krakatoa archipelago. Sumatra is an elongated landmass spanning a diagonal northwest–southeast axis. The Indian Ocean borders the northwest, west, and southwest coasts of Sumatra, with the island chain of Simeulue, Nias, Mentawai, and Enggano off the western coast.
