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Land-vertebrate Age
In paleontology, biochronology is the correlation in time of biological events using fossils. In its strict sense, it refers to the use of assemblages of fossils that are not tied to stratigraphic sections (in contrast to biostratigraphy, where they are). Collections of land mammal ages have been defined for every continent except Antarctica, and most are correlated with each other indirectly through known evolutionary lineages. A combination of argon–argon dating and magnetic stratigraphy allows a direct temporal comparison of terrestrial events with climate variations and mass extinctions. Comparison with biostratigraphy In sedimentary rocks, fossils are the only widely applicable tool for time correlation. Evolution leaves a record of progressive change, sequential and nonrepeating. A rock unit has a characteristic assemblage of fossils, independent of its lithology. Thus, the fossils can be used to compare the ages of different rock units. The basic unit of biochronol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Rhythm
Biological rhythms are repetitive biological processes. Some types of biological rhythms have been described as biological clocks. They can range in frequency from microseconds to less than one repetitive event per decade. Biological rhythms are studied by chronobiology. In the biochemical context biological rhythms are called biochemical oscillations. The variations of the timing and duration of biological activity in living organisms occur for many essential biological processes. These occur (a) in animals (eating, sleeping, mating, hibernating, migration, cellular regeneration, etc.), (b) in plants (leaf movements, photosynthetic reactions, etc.), and in microbial organisms such as fungi and protozoa. They have even been found in bacteria, especially among the cyanobacteria (aka blue-green algae, see bacterial circadian rhythms). Circadian rhythm The best studied rhythm in chronobiology is the circadian rhythm, a roughly 24-hour cycle shown by physiological processes in all th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depositional Environment
In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record. In most cases, the environments associated with particular rock types or associations of rock types can be matched to existing analogues. However, the further back in geological time sediments were deposited, the more likely that direct modern analogues are not available (e.g. banded iron formations). Types of depositional environments Continental * – type of Fluvial deposit. Caused by moving water in a fan shape (Alluvial Fan) and containing mostly impermeable and nonporous sediments well sorted. * . Often in deserts and coastal regions and well sorted, large scale cross-beds * – processes due to moving water, mainly streams. Common sediments are g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bison
A bison (: bison) is a large bovine in the genus ''Bison'' (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant taxon, extant and numerous extinction, extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North America, is the more numerous. Although colloquially referred to as a buffalo in the United States and Canada, it is only distantly related to the true buffalo. The North American species is composed of two subspecies, the Plains bison, ''B. b. bison'', and the generally more northern wood bison, ''B. b. athabascae''. A third subspecies, the eastern bison (''B. b. pennsylvanicus'') is no longer considered a valid taxon, being a junior synonym of ''B. b. bison''. Historical references to "woods bison" or "wood bison" from the Eastern United States refer to this synonym animal (and to their eastern woodland habitat), not to ''B. b. athabascae'', wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rancho La Brea
Rancho La Brea was a Mexican land grant in present-day Los Angeles County, California, given in 1828 to Antonio Jose Rocha and Nemisio Dominguez by José Antonio Carrillo, the alcalde of Los Angeles. Rancho La Brea consisted of one square league of land of what is now Wilshire's Miracle Mile, Hollywood, and parts of West Hollywood. The grant included the famous La Brea Tar Pits. History The title awarded by the alcalde in 1828 was confirmed by José María de Echeandía, governor of Alta California; in 1840, it was reconfirmed by Governor Juan Alvarado. With the cession of California to the United States after the Mexican–American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored. As required by the Land Act of 1851, a claim was filed by Antonio José Rocha, José Jorge Rocha, and Josefa de la Merced de Jordan with the Public Land Commission in 1852, but it was rejected in 1860. As a lawyer and surveyor, Henry Hancock worked f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rancholabrean
The Rancholabrean North American Land Mammal Age on the geologic timescale is a North American faunal stage in the North American Land Mammal Ages chronology (NALMA),Sanders, A.E., R.E. Weems, and L.B. Albright III (2009) Formalization of the mid-Pleistocene "Ten Mile Hill beds" in South Carolina with evidence for placement of the Irvingtonian–Rancholabrean boundary, ''Museum of Northern Arizona Bulletin'' 64:369-375 named after the famed Rancho La Brea fossil site (more commonly known as the La Brea tar pits) in Los Angeles, California.Savage, D.E. (1951) Late Cenozoic vertebrates of the San Francisco Bay region, ''University of California Publications, Bulletin of the Department of Geological Sciences'' 28:215-314 The Rancholabrean is characterized by the presence of the genus ''Bison,'' which appeared in northwestern North America during the Illinoian (globally known as the Penultimate Glacial Period or Marine Isotope Stage 6) around 190-130,000 years ago, before becoming es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bison Antiquus P1350762
A bison (: bison) is a large bovine in the genus ''Bison'' (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North America, is the more numerous. Although colloquially referred to as a buffalo in the United States and Canada, it is only distantly related to the true buffalo. The North American species is composed of two subspecies, the Plains bison, ''B. b. bison'', and the generally more northern wood bison, ''B. b. athabascae''. A third subspecies, the eastern bison (''B. b. pennsylvanicus'') is no longer considered a valid taxon, being a junior synonym of ''B. b. bison''. Historical references to "woods bison" or "wood bison" from the Eastern United States refer to this synonym animal (and to their eastern woodland habitat), not to ''B. b. athabascae'', which was not found in the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Czech Republic
The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The Czech Republic has a hilly landscape that covers an area of with a mostly temperate Humid continental climate, continental and oceanic climate. The capital and largest city is Prague; other major cities and urban areas include Brno, Ostrava, Plzeň and Liberec. The Duchy of Bohemia was founded in the late 9th century under Great Moravia. It was formally recognized as an Imperial Estate of the Holy Roman Empire in 1002 and became Kingdom of Bohemia, a kingdom in 1198. Following the Battle of Mohács in 1526, all of the Lands of the Bohemian Crown were gradually integrated into the Habsburg monarchy. Nearly a hundred years later, the Protestantism, Protestant Bohemian Revolt led to the Thirty Years' War. After the Battle of White ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klonk
Klonk is a national nature monument in the Bohemian Karst Protected Landscape Area in the Czech Republic. It lies in the northern part of the municipality of Suchomasty, approximately south of Beroun. It is globally recognized as a geologically important location due to the presence of the Global Boundary Stratotype Section and Point (GSSP) marking the boundary between Silurian and Devonian periods. The boundary was set based on the first appearance of the graptolite '' Monograptus uniformis'' in the bed number 20. The stratotype was ratified on 8 February 1972 by the International Union of Geological Sciences in Montreal as the first formally accepted GSSP. History The positioning of the boundary between Silurian and Devonian has been a matter of discussion since the 19th century. The so-called hercynian question was resolved only after the ratification of the GSSP in 1972. The monument was declared as a protected area in 1977. IUGS geological heritage site In respect of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monograptus
''Monograptus'' is a genus of graptolites in the order Graptoloidea. This particular genus is the last stage of the graptoloid evolution before its extinction in the early Devonian. A characteristic of the genus includes one uniserial stipes with very elaborate thecae. This particular genus contains large number of graptolite species and may not be monophyletic. Biostratigraphic significance The International Commission on Stratigraphy (ICS) has assigned the First Appearance Datum (FAD) of ''Monograptus uniformis'' as the defining biological marker for the start of the Lochkovian, 419.2 ± 3.2 million years ago, the earliest stage of the Devonian. page 5. Retrieved 2015-06-16. ICS has assigned the FAD of ''Monograptus parultimus'' defining biological marker for the start of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago (Megaannum, Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of history of life#Colonization of land, life on land occurred during the Devonian, as free-spore, sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaf, leaves and true roots, and by the end of the period the first seed-bearing plants (Pteridospermatophyta, pteridospermatophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 23.5 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 third and shortest period of the Paleozoic Era, and the third of twelve periods of the Phanerozoic Eon. 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) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
