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Thuchomyces
''Thuchomyces'' (sometimes mistakenly called “Thucomyces”) is a genus of Archean fossils from the Witwatersrand of South Africa, and is the earliest macroscopic land life known. The generic name derives from thucholite, the carbonaceous material which ''Thuchomyces'' is preserved in, and the Ancient Greek word "myces", meaning "fungus". The specific name, ''lichenoides'', derives from its similarity to some modern lichens. Description ''Thuchomyces'' resembles modern columnar biomats, alongside certain lichens, however the latter are far more recent, only having appeared ''at most'' 300 million years ago, and therefore it almost certainly is not a lichen, or even a eukaryote at all. Some fossils have a round structure at their tip, interpreted as a diaspore, and these structures can also be observed in the rock surrounding the fossils. The internal structure of ''Thuchomyces'' consists of a network of hyphae, made of intensely branching cells possibly connected via anasto ... [...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] |
Witwatersrand
The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, which account for the name Witwatersrand, meaning 'white water ridge' in Afrikaans.Truswell, J.F. (1977). ''The Geological Evolution of South Africa''. pp. 21, 27–28, 33–36. Cape Town: Purnell. This east-west-running scarp can be traced with only one short gap, from Bedfordview (about west of O.R. Tambo International Airport) in the east, through Johannesburg and Roodepoort, to Krugersdorp in the west (see the diagram at left below).Norman, N.; Whitfield, G. (2006) ''Geological Journeys''. pp. 38–49, 60–61. Cape Town: Struik Publishers. The scarp forms the northern edge of a plateau (or ridge) which rises about above the surrounding plains of the Highveld. A number of picturesque Johannesburg suburbs, including Observatory, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archean Life
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] |
Fossil Taxa Described In 1977
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of '' Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before print. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decomposer
Decomposers are organisms that break down dead organisms and release the nutrients from the dead matter into the environment around them. Decomposition relies on chemical processes similar to digestion in animals; in fact, many sources use the words digestion and decomposition interchangeably. In both processes, complex molecules are chemically broken down by enzymes into simpler, smaller ones. The term "digestion," however, is commonly used to refer to food breakdown that occurs within animal bodies, and results in the absorption of nutrients from the gut into the animal's bloodstream. This is contrasted with external digestion, meaning that, rather than swallowing food and then digesting it using enzymes located within a GI tract, an organism instead releases enzymes directly onto the food source, which is what decomposers do as compared to animals. After allowing the enzymes time to digest the material, the decomposer then absorbs the nutrients from the environment into its cells. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinomycetes
The Actinomycetales is an Scientific classification, order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally Gram-positive bacteria, gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycetes can form rod- or coccoid-shaped forms, while others can form spores on aerial hyphae. Actinomycetales bacteria can be infected by bacteriophages, which are called actinophages. Actinomycetales can range from harmless bacteria to pathogens with resistance to antibiotics. Reproduction Actinomycetales have 2 main forms of reproduction: spore formation and hyphae fragmentation. During reproduction, Actinomycetales can form conidiophores, sporangiospores, and oidiospores. In reproducing through hyphae fragmentation, the hyphae formed by Actinomycetales can be a fifth to half the size of fungal hyphae, and bear long spore chains. Presence and associations Actinomycetales can be found mostly in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventifacts
A ventifact (also wind-faceted stone, windkanter) is a rock that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals. The word "Ventifact" is derived from the Latin word "Ventus" meaning 'wind'. These geomorphic features are most typically found in arid environments where there is little vegetation to interfere with aeolian particle transport, where there are frequently strong winds, and where there is a steady but not overwhelming supply of sand. Ventifacts can be abraded to eye-catching natural sculptures such as the main features of the White Desert National Park near Farafra Oasis in Egypt. In moderately tall, isolated rock outcrops, mushroom-shaped pillars of rock may form as the outcrop is eroded by saltating sand grains. This occurs because, even in strong winds, sand grains cannot be continuously held in the air. Instead, the particles bounce along the ground, rarely reaching higher than a few feet above the Earth. Over time, the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleosol
In Earth science, geoscience, paleosol (''palaeosol'' in Great Britain and Australia) is an ancient soil that formed in the past. The definition of the term in geology and paleontology is slightly different from its use in soil science. In geology and paleontology, a paleosol is a former soil preserved by burial underneath either sediments (alluvium or loess) or volcanic deposits (lava flows or volcanic ash), which in the case of older deposits have Lithification, lithified into Rock (geology), rock. In Quaternary geology, sedimentology, paleoclimatology, and geology in general, it is the typical and accepted practice to use the term "paleosol" to designate such "''fossil soils''" found buried within sedimentary and volcanic deposits exposed in all continents. In soil science the definition differs slightly: paleosols are soils formed long ago that have no relationship in their chemical and physical characteristics to the present-day climate or vegetation. Such soils are found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diskagma
''Diskagma'' ("disc-like fragment") is a genus of problematic fossil from a Paleoproterozoic (2200 million years old) paleosol from South Africa, and significant as one of the oldest likely eukaryotes and some of the earliest evidence for life on land. Description ''Diskagma buttonii'' is a small fossil less than 1mm in length found within the surface horizon of a vertisol paleosol above the Hekpoort Basalt dated to 2200 million years old. The opacity of the matrix and the size of the fossil meant that its three dimensional structure required imaging by computer-assisted x-ray tomography using a cyclotron source The fossils are shaped like an urn with an apical cup, which is filled with filamentous structures whose exact nature is uncertain due to recrystallization of the matrix under greenschist facies metamorphism. The base of these hollow urns is a system of hollow tubes running over the paleosol and connecting the urns into groups. The walls of ''Diskagma'' have scattered s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoproterozoic
The Paleoproterozoic Era (also spelled Palaeoproterozoic) is the first of the three sub-divisions ( eras) of the Proterozoic eon, and also the longest era of the Earth's geological history, spanning from (2.5–1.6 Ga). It is further subdivided into four geologic periods, namely the Siderian, Rhyacian, Orosirian and Statherian. Paleontological evidence suggests that the Earth's rotational rate ~1.8 billion years ago equated to 20-hour days, implying a total of ~450 days per year. It was during this era that the continents first stabilized. Atmosphere The Earth's atmosphere was originally a weakly reducing atmosphere consisting largely of nitrogen, methane, ammonia, carbon dioxide and inert gases, in total comparable to Titan's atmosphere. When oxygenic photosynthesis evolved in cyanobacteria during the Mesoarchean, the increasing amount of byproduct dioxygen began to deplete the reductants in the ocean, land surface and the atmosphere. Eventually all surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anastomoses
An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection may be normal (such as the foramen ovale (heart), foramen ovale in a fetus' heart) or abnormal (such as the atrial septal defect#Patent foramen ovale, patent foramen ovale in an adult's heart); it may be acquired (such as an arteriovenous fistula) or innate (such as the arteriovenous shunt of a metarteriole); and it may be natural (such as the aforementioned examples) or artificial (such as a surgical anastomosis). The reestablishment of an anastomosis that had become blocked is called a reanastomosis. Anastomoses that are abnormal, whether congenital disorder, congenital or acquired, are often called fistulas. The term is used in medicine, biology, mycology, geology, and geography. Etymology Anastomosis: medical or Modern Latin, from Greek ἀ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
