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Small Carbonaceous Fossil
Small carbonaceous fossils (SCFs) are sub-millimetric organic remains of organisms preserved in sedimentary strata. This category of fossils has traditionally included robust or thick-walled entities such as plant spores, acritarchs and chitinozoa, but the term 'SCFs' is usually applied to more fragile remnants of animals that can only be extracted through a delicate maceration technique. SCFs are relatively widespread and abundant, and can potentially preserve both mineralized and non-mineralized parts of organisms. Since SCFs can preserve the remains of non-biomineralized organisms, they have been viewed as a relatively untapped record of animal evolution, which has the potential to circumvent some of the biases of the shelly fossil record. Extraction SCFs are typically preserved in fine-grained siliciclastic rocks, and are too small to be fruitfully examined on bedding planes. Instead, they are extracted by dissolving the rock in acid. Traditional palynological preparations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian Arthropod Cuticle With Setae
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acritarch
Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups. Their diversity reflects major ecological events such as the appearance of predation and the Cambrian explosion. Definition Acritarchs were originally defined as non-acid soluble (i.e. non-carbonate, non-siliceous) organic-walled microfossils consisting of a central cavity, and whose biological affinities cannot be determined with certainty. Most commonly they are composed of thermally altered acid insoluble carbon compounds (kerogen). Acritarchs may include the remains of a wide range of quite different kinds of organisms—ranging from the egg cases of small metazoans to resting cysts of many kinds of chlorophyta (green algae). It is likely that most acritarch species from the Paleozoic represent various stages of the life cycle of algae that were ancestral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chitinozoa
Chitinozoa (singular: chitinozoan, plural: chitinozoans) are a group of flask-shaped, organic walled marine microfossils produced by an as yet unknown organism. Common from the Ordovician to Devonian periods (i.e. the mid-Paleozoic), the millimetre-scale organisms are abundant in almost all types of marine sediment across the globe. This wide distribution, and their rapid pace of evolution, makes them valuable biostratigraphic markers. Their bizarre form has made classification and ecological reconstruction difficult. Since their discovery in 1931, suggestions of protist, plant, and fungal affinities have all been entertained. The organisms have been better understood as improvements in microscopy facilitated the study of their fine structure, and it has been suggested that they represent either the eggs or juvenile stage of a marine animal. However, recent research has suggested that they represent the hard shell of a group of protists with uncertain affinities. Chitinozoan ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whole Chitinozoan Cropped
Whole may refer to: Music * Whole note, or semibreve * Whole step, or major second * ''Whole'' (Jessa Anderson album) or the title song, 2014 * ''Whole'' (Soil album), 2013 * ''Whole'', an EP by Pedro the Lion, 1997 * "Whole", a song by Basement from '' Colourmeinkindness'', 2012 * "Whole", a song by Flaw from ''Through the Eyes'', 2001 * "Whole", a song by Jacob Whitesides, 2019 Other uses * Whole (campaign), a British anti-stigma mental health campaign * ''Whole'' (film), a 2003 American documentary by Melody Gilbert * Whole milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modulating ..., milk which has not had fat removed See also * Holism, a philosophical and social theory {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palynology
Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits including sediments of any age. The condition and identification of those particles, organic and inorganic, give the palynologist clues to the life, environment, and energetic conditions that produced them. The term is commonly used to refer to a subset of the discipline, which is defined as "the study of microscopic objects of macromolecular organic composition (i.e., compounds of carbon, hydrogen, nitrogen and oxygen), not capable of dissolution in hydrochloric or hydrofluoric acids". It is the science that studies contemporary and fossil palynomorphs (paleopalynology), including pollen, spores, orbicules, dinocysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter (POM) and kerogen found in sed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chitinozoan
Chitinozoa (singular: chitinozoan, plural: chitinozoans) are a group of flask-shaped, organic walled marine microfossils produced by an as yet unknown organism. Common from the Ordovician to Devonian periods (i.e. the mid-Paleozoic), the millimetre-scale organisms are abundant in almost all types of marine sediment across the globe. This wide distribution, and their rapid pace of evolution, makes them valuable biostratigraphic markers. Their bizarre form has made classification and ecological reconstruction difficult. Since their discovery in 1931, suggestions of protist, plant, and fungal affinities have all been entertained. The organisms have been better understood as improvements in microscopy facilitated the study of their fine structure, and it has been suggested that they represent either the eggs or juvenile stage of a marine animal. However, recent research has suggested that they represent the hard shell of a group of protists with uncertain affinities. Chitinozoan ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Priapulida
Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility, because their general shape and their extensible spiny introvert (eversible) proboscis may resemble the shape of a human penis. They live in the mud and in comparatively shallow waters up to deep. Some species show a remarkable tolerance for hydrogen sulfide and anoxia. They can be quite abundant in some areas. In an Alaskan bay as many as 85 adult individuals of ''Priapulus caudatus'' per square meter has been recorded, while the density of its larvae can be as high as 58,000 per square meter. Together with Echiura and Sipuncula, they were once placed in the taxon Gephyrea, but consistent morphological and molecular evidence supports their belonging to Ecdysozoa, which also includes arthropods and nematodes. Fossil findings show th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wiwaxia
''Wiwaxia'' is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. ''Wiwaxia'' fossils – mainly isolated scales, but sometimes complete, articulated fossils – are known from early Cambrian and middle Cambrian fossil deposits across the globe. The living animal would have measured up to 5 cm (2 inch) when fully grown, although a range of juvenile specimens are known, the smallest being long. ''Wiwaxia's'' affinity has been a matter of debate: Researchers were long split between two possibilities. On the one hand, its rows of scales looked superficially similar to certain scale worms (annelids); conversely, its mouthparts and general morphology suggested a relationship to the shell-less molluscs. More recently, evidence for a molluscan affinity has been accumulating, based on new details of ''Wiwaxias mouthparts, scales, and growth history. The proposed clade Halwaxiida contains ''Wiwaxia'' as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagerstätte
A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus delaying the decomposition of both gross and fine biological features until long after a durable impression was created in the surrounding matrix. ''Lagerstätten'' span geological time from the Neoproterozoic era to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Silurian Waukesha Biota, the Devonian Hunsrück Slates and Gogo Formation, the Carboniferous Mazon Creek, the Jurassic Posidonia Shale and Solnhofen Limestone, the Cretaceous Yixian, Santana, and Agua Nueva formations, the Eocene Green River Formation, the Miocene Foulden Maar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burgess Shale
The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints. The rock unit is a black shale and crops out at a number of localities near the town of Field in Yoho National Park and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south. History and significance The Burgess Shale was discovered by palaeontologist Charles Walcott on 30 August 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, daughter, and wife, establishing a quarry on the flanks of Fossil Ridge. The significance of soft-bodied preservation, and the range of organisms he recognised as new to science, led him to return to the quarry almost every year until 1924. At that point, aged 74, he had amassed over 65,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
