|
Myxomitodes
''Myxomitodes'' (Greek "slime thread like") is a genus of problematic fossil from the Paleoproterozoic (1900 million years old) Stirling Range Formation of Western Australia, and is significant as a very old megascopic fossil, and thus eukaryote. It is a trace fossil and thus evidence of activity, rather than a body fossil. Description ''Myxomitodes stirlingensis'' are irregular markings on the surface of beds, with the superficial appearance of animal trails. They are problematic for such trails because of their great geological age. Unlike fossil trails made by slugs or worms, ''Myxomitodes'' flare and vary in width. Worm and slug trails are long, so generally run off the edges of rock slabs. ''Myxomitodes'' in contrast is short, with one end tapering and the other forming a bulbous structure. Biological affinities ''Myxomitodes stirlingensis'' is a problematic fossil of controversial biological affinities. At first it was interpreted as a trail of a soft-bodied worm-like a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictyostelid
The dictyostelids (Dictyostelia/Dictyostelea, International Code of Zoological Nomenclature, ICZN, or Dictyosteliomycetes, ICBN) are a group of cellular slime molds, or social amoebae. Multicellular behavior When food (normally bacteria) is readily available dictyostelids behave as individual amoebae, which feed and divide normally. However, when the food supply is exhausted, they aggregate to form a multicellular assembly, called a pseudoplasmodium, Grex (biology), grex, or slug (not to be confused with the gastropoda, gastropod mollusca, mollusc called a slug). The grex has a definite anterior and posterior, responds to light and temperature gradients, and has the ability to migrate. Under the correct circumstances the grex matures forming a sorocarp (fruiting body) with a stalk supporting one or more Sorus, sori (balls of spores). These spores are inactive cells protected by resistant cell walls, and become new amoebae once food is available. In ''Acytostelium'', the soro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryota
Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the Three-domain system, three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard (archaea), Asgard archaea. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass (ecology), biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as Flagellated cell, flagellated phagotrophs. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stirling Myxomitodes Detail
Stirling (; sco, Stirlin; gd, Sruighlea ) is a City status in the United Kingdom, city in Central Belt, central Scotland, northeast of Glasgow and north-west of Edinburgh. The market town#Scotland, market town, surrounded by rich farmland, grew up connecting the royal Stirling Castle, citadel, the medieval old town with its merchants and tradesmen, the Stirling Old Bridge, Old Bridge and the port. Located on the River Forth, Stirling is the administrative centre for the Stirling (council area), Stirling council area, and is traditionally the county town of Stirlingshire. Proverbially it is the strategically important "Gateway to the Highlands". It has been said that "Stirling, like a huge brooch clasps Scottish Highlands, Highlands and Scottish Lowlands, Lowlands together". Similarly "he who holds Stirling, holds Scotland" is often quoted. Stirling's key position as the lowest bridging point of the River Forth before it broadens towards the Firth of Forth made it a focal poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils Of Australia
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, Seashell, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in #Resin, amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock stratum, strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grex (biology)
A grex, (also called a pseudoplasmodium, or slug) starts as a crowd of single-celled amoebae of the groups Acrasiomycota or Dictyosteliida; ''grex'' is the Latin word for ''flock''. The cells flock together, forming a mass that behaves as an organised, slug-like unit. Before they get stimulated to crowd together to form a grex, the amoebae simply wander as independent cells grazing on bacteria and other suitable food items. They continue in that way of life as long as conditions are favourable. When the amoebae are stressed, typically by a shortage of food, they form a grex. According to species and circumstances, details of the shape of the grex and how it may form will vary but typically the stressed amoebae first produce pheromones that stimulate the flock to vertically assemble in a column. When the column of aggregated cells becomes too high and narrow to stay upright, it topples and becomes a slug-shaped mass: the grex. The grex is mobile; in its form as a slug-like unit i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gromia
''Gromia'' is a genus of protists, closely related to foraminifera, which inhabit marine and freshwater environments. It is the only genus of the family Gromiidae. ''Gromia'' are ameboid, producing filose pseudopodia that extend out from the cell's proteinaceous test through a gap enclosed by the cell's oral capsule. The test, a shell made up of protein that encloses the cytoplasm, is made up of several layers of membrane, which resemble honeycombs in shape — a defining character of this genus. ''Gromia'' were first discovered in shallow waters, with members of the best-characterized species ''Gromia oviformus'' often found inhabiting rock surfaces, sediments, or seaweed holdfasts. However, research from the 1990s and early 2000s identified gromiids inhabiting depths up to 4,392 m, leading to several new deep-sea ''Gromia'' species being described and recognized. A recent study of the deep sea species ''Gromia sphaerica'' revealed that it produces traces on the seafloor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stirling Myxomitodes Reconstruction
Stirling (; sco, Stirlin; gd, Sruighlea ) is a City status in the United Kingdom, city in Central Belt, central Scotland, northeast of Glasgow and north-west of Edinburgh. The market town#Scotland, market town, surrounded by rich farmland, grew up connecting the royal Stirling Castle, citadel, the medieval old town with its merchants and tradesmen, the Stirling Old Bridge, Old Bridge and the port. Located on the River Forth, Stirling is the administrative centre for the Stirling (council area), Stirling council area, and is traditionally the county town of Stirlingshire. Proverbially it is the strategically important "Gateway to the Highlands". It has been said that "Stirling, like a huge brooch clasps Scottish Highlands, Highlands and Scottish Lowlands, Lowlands together". Similarly "he who holds Stirling, holds Scotland" is often quoted. Stirling's key position as the lowest bridging point of the River Forth before it broadens towards the Firth of Forth made it a focal poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
