Difference between revisions of "Descend"

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==Description==
 
==Description==
'''''Ascending and Descending''''' is a [[Prints|lithograph]] print by the Dutch artist [http://en.wikipedia.org/wiki/M. C. Escher M.C. Escher] which was first printed in March 1960.
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In [https://en.wikipedia.org/wiki/Evolutionary_biology evolutionary biology], a group of [[organisms]] have common '''descent''' if they have a common [[ancestor]]. "There is strong [[quantitative]] [[support]], by a [[formal]] test" for the [[theory]] that all living [[organisms]] on [[Earth]] are descended from a common ancestor.
  
The [[original]] [[print]] measures 14" x 11 1/4”. The lithograph depicts a large building roofed by a never-ending staircase. Two lines of identically dressed men appear on the staircase, one line ascending whilst the other descends. Two figures sit apart from the people on the [[eternal|endless]] staircase: one in a secluded courtyard, the other on a lower set of stairs. While most two-[[dimensional]] artists use [[relative]] proportions to [[create]] an [[illusion]] of depth, Escher here and elsewhere uses conflicting proportions to create the visual [[paradox]].
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[https://en.wikipedia.org/wiki/Charles_Darwin Charles Darwin] proposed the [[theory]] of universal common descent through an [[evolutionary]] [[process]] in [https://en.wikipedia.org/wiki/On_the_Origin_of_Species ''On the Origin of Species''], saying, "There is a grandeur in this view of life, with its several [[powers]], having been originally breathed into a few forms or into one".
  
''Ascending and Descending'' was [[influence]]d by, and is an artistic implementation of, the [http://en.wikipedia.org/wiki/Lionel_Penrose Penrose stairs], an impossible object; Lionel Penrose had first published his concept in the February, 1958 issue of the ''British Journal of Psychology''. Escher developed the theme further in his [[print]] ''Waterfall'', which appeared in 1961.
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The last [[universal]] [[ancestor]] (LUA) (or last universal common ancestor, LUCA), that is, the most recent common ancestor of all currently living [[organisms]], is believed to have appeared about 3.9 billion years ago.
  
==References in popular culture==
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In [https://en.wikipedia.org/wiki/The_Ancestor%27s_Tale ''The Ancestor's Tale''], [https://en.wikipedia.org/wiki/Richard_Dawkins Richard Dawkins] coined the word concestor, as a substitute for common ancestor or most recent common ancestor. This new [[word]] is very gradually entering [[scientific]] parlance.
* [http://www.voidgamers.com/channel/HirstArts/HADD7/b.356.r.386.html Ascending and Descending] A wonderful 3D forced perspective model was build as part of a kit building contest
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==Descent and the family==
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Descent, like [[family]] systems, is one of the major [[concepts]] of [[anthropology]]. [[Cultures]] worldwide [[possess]] a wide range of systems of tracing kinship and descent. Anthropologists break these down into simple [[concepts]] about what is [[thought]] to be common among many different cultures.
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*Descent groups
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A ''descent group'' is a [[social]] [[group]] whose members claim [[common]] [[ancestry]]. A unilineal [[society]] is one in which the descent of an [[individual]] is reckoned either from the [[mother]]'s or the [[father]]'s line of descent. With matrilineal descent individuals belong to their mother's descent group. ''Matrilineal descent'' includes the mother's brother, who in some societies may pass along [[inheritance]] to the sister's children or [[succession]] to a sister's son. With ''patrilineal descent'', [[individuals]] belong to their father's descent group. Societies with the [https://en.wikipedia.org/wiki/Iroquois Iroquois] kinship system, are typically uniliineal, while the Iroquois proper are specifically matrilineal.
  
==Sources==
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In a [[society]] which reckons descent bilaterally (bilineal), descent is reckoned through both father and mother, without unilineal descent groups. Societies with the [https://en.wikipedia.org/wiki/Eskimo Eskimo] kinship system, like the Eskimo proper, are typically bilateral. The egocentrid kindred group is also typical of bilateral societies.
*Locher, J.L. (2000). ''The Magic of M. C. Escher''. ISBN 0-8109-6720-0.
 
  
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Some [[societies]] reckon descent patrilineally for some [[purposes]], and matrilineally for others. This arrangement is sometimes called double descent. For instance, certain [[property]] and titles may be inherited through the [[male]] line, and others through the [[female]] line.
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Societies can also consider descent to be ambilineal (such as Hawaiian kinship) where offspring determine their lineage through the matrilineal line or the patrilineal line.
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==See also==
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*'''''[[Descending Sons]]'''''
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[[Category: Biology]]
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[[Category: Anthropology]]
 
[[Category: General Reference]]
 
[[Category: General Reference]]

Latest revision as of 23:45, 12 December 2020

Lighterstill.jpg

Ascending and Descending.jpg

Etymology

descend

c.1300, from Old.French. descendre, from L. descendere, from de- "down" + scandere "to climb," from PIE base *skand- "jump." Sense of "originate from" is c.1375. Descent is attested from c.1330; descendant "offspring" is from 1600.

Description

In evolutionary biology, a group of organisms have common descent if they have a common ancestor. "There is strong quantitative support, by a formal test" for the theory that all living organisms on Earth are descended from a common ancestor.

Charles Darwin proposed the theory of universal common descent through an evolutionary process in On the Origin of Species, saying, "There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one".

The last universal ancestor (LUA) (or last universal common ancestor, LUCA), that is, the most recent common ancestor of all currently living organisms, is believed to have appeared about 3.9 billion years ago.

In The Ancestor's Tale, Richard Dawkins coined the word concestor, as a substitute for common ancestor or most recent common ancestor. This new word is very gradually entering scientific parlance.

Descent and the family

Descent, like family systems, is one of the major concepts of anthropology. Cultures worldwide possess a wide range of systems of tracing kinship and descent. Anthropologists break these down into simple concepts about what is thought to be common among many different cultures.

  • Descent groups

A descent group is a social group whose members claim common ancestry. A unilineal society is one in which the descent of an individual is reckoned either from the mother's or the father's line of descent. With matrilineal descent individuals belong to their mother's descent group. Matrilineal descent includes the mother's brother, who in some societies may pass along inheritance to the sister's children or succession to a sister's son. With patrilineal descent, individuals belong to their father's descent group. Societies with the Iroquois kinship system, are typically uniliineal, while the Iroquois proper are specifically matrilineal.

In a society which reckons descent bilaterally (bilineal), descent is reckoned through both father and mother, without unilineal descent groups. Societies with the Eskimo kinship system, like the Eskimo proper, are typically bilateral. The egocentrid kindred group is also typical of bilateral societies.

Some societies reckon descent patrilineally for some purposes, and matrilineally for others. This arrangement is sometimes called double descent. For instance, certain property and titles may be inherited through the male line, and others through the female line.

Societies can also consider descent to be ambilineal (such as Hawaiian kinship) where offspring determine their lineage through the matrilineal line or the patrilineal line.

See also