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Bacteria Phyla
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit the air, soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in mutualistic, commensal and para ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archean
The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and the Phanerozoic. The Archean represents the time period from (million years ago). The Late Heavy Bombardment is hypothesized to overlap with the beginning of the Archean. The Huronian glaciation occurred at the end of the eon. The Earth during the Archean was mostly a ocean world, water world: there was continental crust, but much of it was under an ocean deeper than today's oceans. Except for some rare Relict (geology), relict crystals, today's oldest continental crust dates back to the Archean. Much of the geological detail of the Archean has been destroyed by subsequent activity. The Earth's atmosphere was also vastly different in atmospheric chemistry, composition from today's: the prebiotic atmosphere was a reducing atmosphere rich in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferdinand Cohn
Ferdinand Julius Cohn (24 January 1828 – 25 June 1898) was a German biologist. He is one of the founders of modern bacteriology and microbiology. Biography Ferdinand Julius Cohn was born in the Jewish quarter of Breslau in the Prussian Province of Silesia (modern-day Wrocław, Poland). His father, Issak Cohn, was a successful merchant and manufacturer who for some time held the post of Austro-Hungarian consul. He was the elder brother of humorist and playwright Oskar Justinus Cohn and of historian and jurist . He was considered a child prodigy, and could read at the age of two. He also suffered hearing impairment from a young age. He entered the in 1835 at the age or 6 or 7, and the University of Breslau in 1842 or 1844. There he studied botany under Heinrich Göppert and Christian Nees von Esenbeck. Cohn was refused admission to the University of Breslau's doctoral program because of his Jewish background. He thus continued his studies at the University of Berlin, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Crust
Earth's crust is its thick outer shell of rock, referring to less than one percent of the planet's radius and volume. It is the top component of the lithosphere, a solidified division of Earth's layers that includes the crust and the upper part of the mantle. The lithosphere is broken into tectonic plates whose motion allows heat to escape the interior of Earth into space. The crust lies on top of the mantle, a configuration that is stable because the upper mantle is made of peridotite and is therefore significantly denser than the crust. The boundary between the crust and mantle is conventionally placed at the Mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. The temperature of the crust increases with depth, reaching values typically in the range from about at the boundary with the underlying mantle. The temperature increases by as much as for every kilometer locally in the upper part of the crust. Composition File:Elementa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
