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Sinistral and dextral
Not to be confused with Dexter and sinister.
Sinistral and dextral are scientific terms that
describechirality (handedness) or relative direction in a num-ber
of disciplines. The terms are derived from the Latinwords for left
(sinister) and right (dexter). Other dis-ciplines have different
terms (such as dextro- and laevo-rotary, in chemistry, or clockwise
and anticlockwise inphysics) or simply use left and right (as in
anatomy).Relative direction and chirality are distinct concepts.
Rel-ative direction is from the point of view of the observer.A
completely symmetrical object has a left and a rightside, from the
observers point of view, if the top andbottom and direction of
observation are defined. Chi-rality, however, is
observer-independent: no matter howone looks at a right-hand screw
thread, it remains differ-ent from a left-hand screw thread.
Therefore, a symmet-rical object has sinistral and dextral
directions arbitrarilydefined by the position of the observer,
while an objectthat has chirality can have sinistral and dextral
directionsdefined by characteristics of the object, no matter the
po-sition of the observer.
1 Geology
Main article: Fault (geology)In geology the terms sinistral and
dextral refer to the
Schematic illustration of the two strike-slip fault types. The
viewis of the Earths surface from above.
horizontal component of movement of blocks on eitherside of a
fault or the sense of movement within a shearzone. These are terms
of relative direction, as the move-ment of the blocks are described
relative to each otherwhen viewed from above. Movement is sinistral
(left-handed) if the block on the other side of the fault movesto
the left, or if straddling the fault the left side moves to-ward
the observer. Movement is dextral (right-handed) if
the block on the other side of the fault moves to the right,or
if straddling the fault the right side moves toward
theobserver.[1]
2 Biology
Left: The normally sinistral (left-handed) shell of the
NorthernHemisphere Neptunea angulata.Right: The normally dextral
(right-handed) shell of Neptuneadespecta, found mainly in the
Southern Hemisphere
Flatfish are asymmetrical, with both eyes lying on the same
sideof the head
2.1 Gastropods
Main article: Gastropod shell
1
https://en.wikipedia.org/wiki/Dexter_and_sinisterhttps://en.wikipedia.org/wiki/Chiralityhttps://en.wikipedia.org/wiki/Relative_directionhttps://en.wikipedia.org/wiki/Latinhttps://en.wikipedia.org/wiki/Dextrorotaryhttps://en.wikipedia.org/wiki/Laevorotaryhttps://en.wikipedia.org/wiki/Laevorotaryhttps://en.wikipedia.org/wiki/Chirality_(chemistry)https://en.wikipedia.org/wiki/Clockwise#Usagehttps://en.wikipedia.org/wiki/Anticlockwisehttps://en.wikipedia.org/wiki/Chirality_(electromagnetism)https://en.wikipedia.org/wiki/Anatomical_terms_of_location#Directional_termshttps://en.wikipedia.org/wiki/Fault_(geology)https://en.wikipedia.org/wiki/Fault_(geology)https://en.wikipedia.org/wiki/Shear_zonehttps://en.wikipedia.org/wiki/Shear_zonehttps://en.wikipedia.org/wiki/Neptunea_angulatahttps://en.wikipedia.org/wiki/Neptunea_despectahttps://en.wikipedia.org/wiki/Neptunea_despectahttps://en.wikipedia.org/wiki/Gastropod_shell
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2 5 EXTERNAL LINKS
Because the coiled shells of gastropods are asymmetrical,they
possess a quality called chirality, the handednessof an
asymmetrical structure.Over 90% [2] of gastropod species have
dextral (right-handed) shells in their coiling. A small minority
ofspecies and genera are almost always sinistral (left-handed). A
very few species show an even mix-ture of dextral and sinistral
individuals (for example,Amphidromus perversus[3]).
2.2 Flatfish
Main article: Flatfish
The most obvious characteristic of flatfish, other thantheir
flatness, is asymmetry because both eyes are on thesame side of the
head in the adult fish. In some fami-lies of flatfish, the eyes are
always on the right side ofthe body (dextral or right-eyed
flatfish), and in others,they are always on the left (sinistral or
left-eyed flatfish).Primitive spiny turbots include equal numbers
of right-and left-sided individuals, and are generally more
sym-metrical than other families.[4]
3 See also Chirality
Left and right (disambiguation)
Laterality
Helicity (disambiguation)
4 Notes[1] Park, R.G. (2004). Foundation of Structural Geology
(3
ed.). Routledge. p. 11. ISBN 978-0-7487-5802-9.
[2] Schilthuizen M. & Davison A. (2005). The
convolutedevolution of snail chirality. Naturwissenschaften
92(11):504515. doi:10.1007/s00114-005-0045-2.
[3] Amphidromus perversus (Linnaeus, 1758)
[4] Chapleau, Francois & Amaoka, Kunio (1998). Paxton,J.R.
& Eschmeyer, W.N., ed. Encyclopedia of Fishes. SanDiego:
Academic Press. xxx. ISBN 0-12-547665-5.
5 External links
https://en.wikipedia.org/wiki/Chiralityhttps://en.wikipedia.org/wiki/Amphidromus_perversushttps://en.wikipedia.org/wiki/Flatfishhttps://en.wikipedia.org/wiki/Spiny_turbothttps://en.wikipedia.org/wiki/Chiralityhttps://en.wikipedia.org/wiki/Left_and_right_(disambiguation)https://en.wikipedia.org/wiki/Lateralityhttps://en.wikipedia.org/wiki/Helicity_(disambiguation)http://books.google.co.uk/books?id=ycASqdxSG3YC&pg=PA11&lpg=PA11&dq=sinistral+dextral+structural+geology#v=onepage&q=sinistral%2520dextral%2520structural%2520geology&f=falsehttps://en.wikipedia.org/wiki/International_Standard_Book_Numberhttps://en.wikipedia.org/wiki/Special:BookSources/978-0-7487-5802-9https://en.wikipedia.org/wiki/Naturwissenschaftenhttps://en.wikipedia.org/wiki/Digital_object_identifierhttps://dx.doi.org/10.1007%252Fs00114-005-0045-2http://www.jaxshells.org/052ddr.htmhttps://en.wikipedia.org/wiki/International_Standard_Book_Numberhttps://en.wikipedia.org/wiki/Special:BookSources/0-12-547665-5
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6 Text and image sources, contributors, and licenses
6.1 Text Sinistral and dextral Source:
http://en.wikipedia.org/wiki/Sinistral%20and%20dextral?oldid=633316919
Contributors: Infrogmation,
Zoicon5, Bkonrad, Macrakis, Hrance, Vsmith, Andrew Gray, BD2412,
Rjwilmsi, Bhny, Kateweb, Agateller, Rolinator, Mwtoews,Tmangray,
Cydebot, Mikenorton, Magioladitis, Arjenwielaard, Moonraker12,
Invertzoo, Alexbot, Qfl247, Addbot, Danno uk, RedBot,Rezabot,
Helpful Pixie Bot, CitationCleanerBot, Arms Jones, OMPIRE and
Anonymous: 7
6.2 Images File:Neptunea_-_links&rechts_gewonden.jpg Source:
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26rechts_gewonden.jpg License: Public domain Contributors: Nyst,
P.H., 1878-1881. Conchyliologie des terrains tertiaires de la
Belgique.-- Ann. Mus. r. Hist. nat. Belg., 3: 1-262 (1878), 28 pls.
(1881). Original artist: Scanned by Tom Meijer
File:Pseudopleuronectes_americanus.jpg Source:
http://upload.wikimedia.org/wikipedia/commons/2/2b/Pseudopleuronectes_americanus.jpg
License: Public domain Contributors: ? Original artist: ?
File:Strike_slip_fault.png Source:
http://upload.wikimedia.org/wikipedia/commons/b/bb/Strike_slip_fault.png
License: CC-BY-SA-3.0 Contributors: Transferred from en.wikipedia
Original artist: Original uploader was Cferrero at en.wikipedia
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License: Public do-main Contributors: Vector version of
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6.3 Content license Creative Commons Attribution-Share Alike
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GeologyBiologyGastropodsFlatfish
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