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More than 99 percent of all species that ever lived (over five billion) [1] are estimated to be extinct. [2] [3] Estimates on the number of Earth's current species range from 10 million to 14 million, [4] with about 1.2 million or 14% documented, the rest not yet described. [5]
Two species are described in the literature: A. ramidus, which lived about 4.4 million years ago [32] during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago [33] (late Miocene). A. ramidus had a small brain, measuring between 300 and 350 cm 3.
Tertiary (/ ˈ t ɜːr. ʃ ə. r i, ˈ t ɜː r. ʃ i ˌ ɛr. i / TUR-shə-ree, TUR-shee-err-ee) [1] is an obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the extinction of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at ...
Lucy Catalog no. AL 288-1 Common name Lucy Species Australopithecus afarensis Age 3.2 million years Place discovered Afar Depression, Ethiopia Date discovered November 24, 1974 ; 50 years ago (1974-11-24) Discovered by Donald Johanson Maurice Taieb Yves Coppens Tom Gray AL 288-1, commonly known as Lucy or Dinkʼinesh, is a collection of several hundred pieces of fossilized bone comprising 40 ...
A megaannus (Ma) represents one million (10 6) years. The geologic time scale or geological time scale ( GTS ) is a representation of time based on the rock record of Earth . It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to ...
The Miocene (/ ˈ m aɪ. ə s iː n,-oʊ-/ MY-ə-seen, -oh-) [6] [7] is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words μείων (meíōn, "less") and καινός (kainós, "new") [8] [9] and means "less recent" because it has 18% fewer modern marine invertebrates ...
For example, at the background rate one species of bird will go extinct every estimated 400 years. [6] Another way the extinction rate can be given is in million species years (MSY). For example, there is approximately one extinction estimated per million species years. [7]
The Mesozoic Era [3] is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods.It is characterized by the dominance of archosaurian reptiles such as the dinosaurs, and of gymnosperms such as cycads, ginkgoaceae and araucarian conifers; a hot greenhouse climate; and the tectonic break-up of Pangaea.