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Leiosphaerid
Leiosphaeridia is a form-genus of acritarchs proposed by Eisenack in 1958. The grouping was refined to represent a more natural group by Jankauskas. Some leiosphaerid acritarchs have been recognised as vaucheriacean algæ. The class represents shallow-water environments. See also * ''Leiosphaeridia ''Leiosphaeridia'' is an extinct genus of algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct cla ...'' References Acritarchs {{paleo-biota-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leiosphaeridia
''Leiosphaeridia'' is an extinct genus of algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ... or acritarchs. The genus of undefined species were found in outcrop ''Morro do Papaléo'' in the town of Mariana Pimentel in Brazil, the geopark Paleorrota. The outcrop date Sakmarian in Permian. See also * Leiosphaerid References {{Taxonbar, from=Q6520099 Acritarch genera Permian life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acritarchs
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 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alga
Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as '' Chlorella'', '' Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the '' Charophyta'', a division of green algae which includes, for example, '' Spirogyra'' and stoneworts. Algae that are carried by water are plankton, specifically phytoplankton. Algae constitute a polyphyletic group since they do not include a common ancestor, and although their plastids seem to have a single or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Eukaryote Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
