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Thectardis
''Thectardis avalonensis'' is a triangular-shaped member of the Ediacaran biota, dating from . The organism took the form of an elongated cone with a central depression, and its apex was anchored to the substrate. Sperling et al. (2011) suggest that ''Thectardis'' was a sponge, while Antcliffe et al. (2014, 2015) instead suggest that it is the decayed remains of rangeomorphs. Morphology The fossils take the form of a triangle with a central depression, suggesting that the original organism was conical. They range from 26 to 165mm in length and from 24 to 96mm in width at the triangular base. The diameter to height ratio of the organism is roughly constant in each location at 1 to 3 in the younger beds, and from 1 to 2.5 in the older beds. The constant ratio suggests that it grew by adding to its body at the base of the cone. The triangle has a raised margin about a quarter of the width of the triangle. The interior either is blank, depressed, or has some vague transverse markin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Ediacaran Genera
The existence of life, especially that of animals, before the Cambrian had long been the subject of debate in paleontology. The apparent suddenness of the Cambrian explosion had no firm explanation, and Charles Darwin himself recognized the challenge it posed for his theory of evolution. While reports of Precambrian organisms have been made since Alexander Murray's 1868 discovery of ''Aspidella'', it wasn't until the discovery of ''Charnia'' in 1956 that considerable evidence of Precambrian life had been presented. The period immediately preceding the Cambrian, the Ediacaran, is now widely accepted of containing animal life. It spans from 635 to 540 million years ago, and covers approximately 2% of Earth's history. Taxonomists have purported a total of 245 described genera from the Ediacaran, 162 of which are accepted as valid. Key * Valid genus - Genera that are accepted by the scientific community * Synonym (taxonomy), Junior synonym - Alternative name for an already existi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran
The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last period of the Proterozoic geologic eon, Eon as well as the last of the so-called "Precambrian supereon", before the beginning of the subsequent Cambrian Period marks the start of the Phanerozoic Eon, where recognizable fossil evidence of life becomes common. The Ediacaran Period is named after the Ediacara Hills of South Australia, where trace fossils of a diverse community of previously unrecognized lifeforms (later named the Ediacaran biota) were first discovered by geologist Reg Sprigg in 1946. Its status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period took namesake from the Ediacara Hills ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newfoundland (island)
Newfoundland ( , ; , ) is a large island within the Canadian province of Newfoundland and Labrador. It is situated off the eastern coast of the Northern America, North American mainland and the geographical region of Labrador. The island contains 29 percent of the province's land area, but is home to over 90% of the province's population, with about 60% of the province's population located on the small southeastern Avalon peninsula. The island is separated from the Labrador Peninsula by the Strait of Belle Isle and from Cape Breton Island by the Cabot Strait. It blocks the mouth of the Saint Lawrence River, creating the Gulf of Saint Lawrence, the world's largest estuary. Newfoundland's nearest neighbour is the French overseas collectivity of Saint Pierre and Miquelon. With an area of , Newfoundland is the List of islands by area, world's 16th-largest island, List of Canadian islands by area, Canada's fourth-largest island, and the largest Canadian island outside Northern Can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran Canada
The Ediacaran ( ) is a geological period of the Neoproterozoic Era that spans 96 million years from the end of the Cryogenian Period at 635 Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last period of the Proterozoic Eon as well as the last of the so-called "Precambrian supereon", before the beginning of the subsequent Cambrian Period marks the start of the Phanerozoic Eon, where recognizable fossil evidence of life becomes common. The Ediacaran Period is named after the Ediacara Hills of South Australia, where trace fossils of a diverse community of previously unrecognized lifeforms (later named the Ediacaran biota) were first discovered by geologist Reg Sprigg in 1946. Its status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period took namesake from the Ediacara Hills in the Nilpena Ediacara National Park, the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran Life
The Ediacaran (; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (). These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined. The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, . This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalon Peninsula
The Avalon Peninsula () is a large peninsula that makes up the southeast portion of the island of Newfoundland in Canada. It is in size. The peninsula is home to 270,348 people, about 52% of the province's population, according to the 2016 Canadian census. The peninsula is the location of St. John's, the provincial capital and largest city. It is connected to the main section of the island by the wide Isthmus of Avalon. The peninsula protrudes into the rich fishing zones near the Grand Banks. Its four major bays ( Trinity Bay, Conception Bay, St. Mary's Bay and Placentia Bay) have long been the centre of Newfoundland's fishing industry. Geography and geology The Avalon Peninsula is pinched into smaller peninsulas formed by St. Mary's Bay and Conception Bay. St. John's is located in the northeast of the peninsula. The Avalon Peninsula is a noted region for Precambrian fossils, and many Lagerstätten of the diverse Ediacaran biota are found on the peninsula. Mistaken Poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holdfast (biology)
A holdfast is a root-like structure that anchors aquatic sessile organisms, such as seaweed, other sessile algae, stalked crinoids, benthic cnidarians, and sponges, to the substrate. Holdfasts vary in shape and form depending on both the species and the substrate type. The holdfasts of organisms that live in muddy substrates often have complex tangles of root-like growths. These projections are called haptera and similar structures of the same name are found on lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...s. The holdfasts of organisms that live in sandy substrates are bulb-like and very flexible, such as those of sea pens, thus permitting the organism to pull the entire body into the substrate when the holdfast is contracted. The holdfasts of organisms that liv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivesheadia
The "ivesheadiomorphs" are a group of fossilised structures known from Ediacaran localities in England and Newfoundland. They are considered to be taphomorphs, representing the poorly preserved biological remains of various contemporary taxa such as ''Charnia'', ''Charniodiscus'', ''Bradgatia'', ''Primocandelabrum'', ''Pectinifrons'' and others, that were effaced by partial decay by micro-organisms following death on the seafloor before burial by sediment. Ivesheadiomorph structures were previously described as distinct organisms, namely ''Ivesheadia lobata'' ("pizza disk"), ''Blackbrookia oaksi'', ''Shepshedia palmata'' and ''Pseudovendia charnwoodensis''. However, all of these fossils have since been rejected as valid taxa. See also * List of Ediacaran genera The existence of life, especially that of animals, before the Cambrian had long been the subject of debate in paleontology. The apparent suddenness of the Cambrian explosion had no firm explanation, and Charles Darwin h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charnia
''Charnia'' is an extinct genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture (thus exhibiting glide reflection, or opposite isometry). The genus ''Charnia'' was named after Charnwood Forest in Leicestershire, England, where the first fossilised specimen was found; the species was named after Roger Mason, a schoolboy who was believed to have initially discovered it. ''Charnia'' is significant because it was the first Precambrian fossil to be recognized as such. The living organism grew on the sea floor, 570 to 550 million years ago, and is believed to have fed on nutrients in the water. Despite ''Charnia'' fern-like appearance, it is not a photosynthetic plant or alga because the nature of the fossil beds where specimens have been found implies that it originally lived in deep water, well below the photic zone where photosynthesis can occur. Diversity Severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mistaken Point (Newfoundland And Labrador)
Mistaken Point Ecological Reserve is a wilderness area and a UNESCO World Heritage Site located at the southeastern tip of Newfoundland's Avalon Peninsula in the Canadian province of Newfoundland and Labrador. The reserve is home to the namesake Mistaken Point Formation, which contains one of the most diverse and well-preserved collections of Precambrian fossils in the world. Ediacaran fossils discovered at the site constitute the oldest known remnants of multicellular life on Earth. Mistaken Point Mistaken Point () is a small headland on the Avalon Peninsula. Historically, Mistaken Point has been mistaken for Cape Race due to the area's typically foggy weather conditions. Sailors making this error would turn north, thinking they had reached Cape Race Harbour, and immediately run into treacherous rocks. History The first fossil to be found in the area, '' Fractofusus misrai'', was discovered in June 1967 by Shiva Balak Misra, an Indian graduate student studying geology at Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animalia
Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, have myocytes and are motility, able to move, can reproduce sexually, and grow from a hollow sphere of Cell (biology), cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million extant taxon, living animal species have been species description, described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from to . They have complex ecologies and biological interaction, interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
