Play Video
1
Taxonomy: Life
Taxonomy: Life's Filing System - Crash Course Biology #19
::2012/06/04::
Play Video
2
Learn Biology: Classification- The Taxonomic Hierarchy
Learn Biology: Classification- The Taxonomic Hierarchy
::2011/01/21::
Play Video
3
Classification of Life
Classification of Life
::2012/03/29::
Play Video
4
Taxonomy (biology)
Taxonomy (biology)
::2014/08/22::
Play Video
5
The Taxonomy Song (For my friends in PreMed)
The Taxonomy Song (For my friends in PreMed)
::2010/03/07::
Play Video
6
Taxonomy and Systematics
Taxonomy and Systematics
::2013/03/13::
Play Video
7
SAT ll Biology- Taxonomy
SAT ll Biology- Taxonomy
::2012/04/19::
Play Video
8
Old & Odd: Archaea, Bacteria & Protists - CrashCourse Biology #35
Old & Odd: Archaea, Bacteria & Protists - CrashCourse Biology #35
::2012/09/24::
Play Video
9
Biology EOC Review - Strands 2&3-Genetics,Evolution,Taxonomy
Biology EOC Review - Strands 2&3-Genetics,Evolution,Taxonomy
::2013/05/03::
Play Video
10
Taxonomy and the Tree of Life
Taxonomy and the Tree of Life
::2011/11/01::
Play Video
11
Fungi: Death Becomes Them - CrashCourse Biology #39
Fungi: Death Becomes Them - CrashCourse Biology #39
::2012/10/22::
Play Video
12
Biology Hierarchical Classification and Taxonomy
Biology Hierarchical Classification and Taxonomy
::2012/02/16::
Play Video
13
CBSE Class 11 - Biology Lessons - 005 - Taxonomy Taxa Category
CBSE Class 11 - Biology Lessons - 005 - Taxonomy Taxa Category
::2013/11/05::
Play Video
14
Biology #9 - Part 1 - Taxonomy of Organisms 00_00_00-00_08_43.wmv
Biology #9 - Part 1 - Taxonomy of Organisms 00_00_00-00_08_43.wmv
::2010/11/23::
Play Video
15
"Taxonomy" | Biology with Educator.com
"Taxonomy" | Biology with Educator.com
::2014/03/10::
Play Video
16
All About - Taxonomy (biology)
All About - Taxonomy (biology)
::2014/11/01::
Play Video
17
Biology: Classifying Evolution Products - Taxonomy
Biology: Classifying Evolution Products - Taxonomy
::2010/09/14::
Play Video
18
Taxonomy and Biology of Tunicate Course 2014
Taxonomy and Biology of Tunicate Course 2014
::2014/10/14::
Play Video
19
JSC 2014 2015   Science Lecture 2   Molecular Biology, Evolutionary Taxonomy, and Phylogenetic Nomen
JSC 2014 2015 Science Lecture 2 Molecular Biology, Evolutionary Taxonomy, and Phylogenetic Nomen
::2014/11/26::
Play Video
20
Taxonomy Ep.1 Introduction to Biology by พุดดิ้ง
Taxonomy Ep.1 Introduction to Biology by พุดดิ้ง
::2014/07/08::
Play Video
21
Taxonomy BIOLOGY EC
Taxonomy BIOLOGY EC
::2013/07/29::
Play Video
22
Biology Project: Plant Taxonomy
Biology Project: Plant Taxonomy
::2010/05/11::
Play Video
23
Biology Unit - Taxonomy and Classification  www. science powerpoint .com
Biology Unit - Taxonomy and Classification www. science powerpoint .com
::2010/07/11::
Play Video
24
Biology #9 - Part 2 -Taxonomy of Organisms 00_08_43-00_12_28.wmv
Biology #9 - Part 2 -Taxonomy of Organisms 00_08_43-00_12_28.wmv
::2010/11/23::
Play Video
25
The Three Domains of Life
The Three Domains of Life
::2012/03/29::
Play Video
26
(BSH 114 Elementary Biology) Taxonomy
(BSH 114 Elementary Biology) Taxonomy
::2014/09/15::
Play Video
27
Classification of Life, Taxonomy with a mention of Phylogeny - High School Biology Regents
Classification of Life, Taxonomy with a mention of Phylogeny - High School Biology Regents
::2012/07/06::
Play Video
28
Biology AS Level - Taxonomy, The Five Kingdoms
Biology AS Level - Taxonomy, The Five Kingdoms
::2012/05/17::
Play Video
29
What is Taxonomy?
What is Taxonomy?
::2013/06/13::
Play Video
30
Biology 101 With Mr. Shoemaker: Taxonomy
Biology 101 With Mr. Shoemaker: Taxonomy
::2012/04/05::
Play Video
31
Modern Taxonomy notes
Modern Taxonomy notes
::2014/03/28::
Play Video
32
Taxonomy & Plants-Taxonomy
Taxonomy & Plants-Taxonomy
::2014/02/21::
Play Video
33
Taxonomy and Classification
Taxonomy and Classification
::2013/03/03::
Play Video
34
Classification (IB Biology)
Classification (IB Biology)
::2013/04/18::
Play Video
35
Pokemon Taxonomy
Pokemon Taxonomy
::2011/08/14::
Play Video
36
Taxonomy, Classification of organisms
Taxonomy, Classification of organisms
::2014/02/12::
Play Video
37
Phylogenetics
Phylogenetics
::2011/06/22::
Play Video
38
Biological basics of Taxonomy by vic the bio babe
Biological basics of Taxonomy by vic the bio babe
::2011/06/04::
Play Video
39
Cladograms
Cladograms
::2012/05/11::
Play Video
40
Classification of Animal Kingdom| Taxonomy of  Hierarchy .wmv
Classification of Animal Kingdom| Taxonomy of Hierarchy .wmv
::2012/05/20::
Play Video
41
Animal Classification: The History of Taxonomy
Animal Classification: The History of Taxonomy
::2010/11/18::
Play Video
42
Classification Rap
Classification Rap
::2007/07/28::
Play Video
43
Biology 1B - Lecture 1: Introduction / Fungi
Biology 1B - Lecture 1: Introduction / Fungi
::2010/01/20::
Play Video
44
Need Help Memorizing the Classification Order in Taxonomy
Need Help Memorizing the Classification Order in Taxonomy
::2009/03/04::
Play Video
45
Taxonomy of Platypus
Taxonomy of Platypus
::2012/05/16::
Play Video
46
Classifications of Animals
Classifications of Animals
::2010/05/04::
Play Video
47
CLASSification & Taxonomy RAP
CLASSification & Taxonomy RAP
::2011/04/27::
Play Video
48
Classification and Taxonomy
Classification and Taxonomy
::2013/01/21::
Play Video
49
Biology 1B - Lecture 34: Introduction to plant morphology an
Biology 1B - Lecture 34: Introduction to plant morphology an
::2010/11/16::
Play Video
50
Invasion Biology - Where Did it Come From, Where is it Going, and Why Don
Invasion Biology - Where Did it Come From, Where is it Going, and Why Don't Some People Like it?
::2012/05/06::
NEXT >>
RESULTS [51 .. 101]
From Wikipedia, the free encyclopedia
  (Redirected from Taxonomic)
Jump to: navigation, search
For other uses, see Taxonomy (disambiguation).

Taxonomy (from Ancient Greek: τάξις taxis, "arrangement," and -νομία -nomia, "method"[1]) is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. Organisms are grouped together into taxa (singular: taxon) and given a taxonomic rank; groups of a given rank can be aggregated to form a super group of higher rank and thus create a taxonomic hierarchy.[2][3] The Swedish botanist Carolus Linnaeus is regarded as the father of taxonomy, as he developed a system known as Linnaean classification for categorization of organisms and binomial nomenclature for naming organisms.

With the advent of such fields of study as phylogenetics, cladistics, and systematics, the Linnaean system has progressed to a system of modern biological classification based on the evolutionary relationships between organisms, both living and extinct. An example of a modern classification is the one published in 2009 by the Angiosperm Phylogeny Group for all living flowering plant families (the APG III system).[4]

Definition[edit]

The exact definition of taxonomy varies from source to source, but the core of the discipline remains: the conception, naming, and classification of organism groups. The exact relationship of systematics and classification to taxonomy also varies because the usage of the terms in biology originated independently.[5] As points of reference, recent definitions of taxonomy are presented below:

  1. Theory and practice of grouping individuals into species, arranging species into larger groups, and giving those groups names, thus producing a classification;[2]
  2. A field of science (and major component of systematics) that encompasses description, identification, nomenclature, and classification;[3]
  3. The science of classification, in biology the arrangement of organisms into a classification.[6]
  4. "The science of classification as applied to living organisms, including study of means of formation of species, etc."[7]
  5. "The analysis of an organism's characteristics for the purpose of classification"[8]
  6. "[Systematics] studies phylogeny to provide a pattern that can be translated into the classification and names of the more inclusive field of taxonomy." (Listed as a desirable but unusual definition[9])

The varied definitions either place taxonomy as a sub-area of systematics (definition 2), invert that relationship (definition 6), or appear to consider the two terms synonymous. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy (definitions 1 and 2), or a part of systematics outside taxonomy. For example, the last definition[8] is paired with the following definition of systematics that places nomenclature outside taxonomy:

  • Systematics: "The study of the identification, taxonomy and nomenclature of organisms, including the classification of living things with regard to their natural relationships and the study of variation and the evolution of taxa".

Alpha taxonomy[edit]

Not to be confused with Alpha diversity.

The term "alpha taxonomy" is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, and the products of research through the end of the nineteenth century.

William Bertram Turrill introduced the term "alpha taxonomy" in a series of papers published in 1935 and 1937 in which he discussed the philosophy and possible future directions of the discipline of taxonomy.[10]

… there is an increasing desire amongst taxonomists to consider their problems from wider view-points, to investigate the possibilities of closer co-operation with their cytological, ecological and genetical colleagues and to acknowledge that some revision or expansion, perhaps of a drastic nature, of their aims and methods may be desirable … Turrill (1935) has suggested that while accepting the older invaluable taxonomy, based on structure, and conveniently designated "alpha", it is possible to glimpse a far-distant taxonomy built up on as wide a basis of morphological and physiological facts as possible, and one in which "place is found for all observational and experimental data relating, even if indirectly, to the constitution, subdivision, origin and behaviour of species and other taxonomic groups". Ideals can, it may be said, never be completely realized. They have, however, a great value of acting as permanent stimulants, and if we have some, even vague, ideal of an "omega" taxonomy we may progress a little way down the Greek alphabet. Some of us please ourselves by thinking we are now groping in a "beta" taxonomy.[10]

Turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy (pages 365–366).

Later authors have used the term in a different sense, to mean the delimitation of species (not subspecies or taxa of other ranks), using whatever investigative techniques are available, and including sophisticated computational or laboratory techniques.[11]

History of taxonomy[edit]

Pre-Linnaean taxonomy[edit]

Early taxonomists[edit]

Taxonomy has been called "the world's oldest profession",[12] and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate. It would always have been important to know the names of poisonous and edible plants and animals in order to communicate this information to other members of the family or group.

Medicinal plant illustrations show up in Egyptian wall paintings from c. 1500 BC.[13] The paintings clearly show that these societies valued and communicated the uses of different species, and therefore had a basic taxonomy in place.

Aristotle to Pliny the Elder[edit]

Historical records show that informally classifying organisms took place at least back to the days of Aristotle (Greece, 384–322 BC),[14] who was the first to begin to classify all living things. Some of the terms he gave to animals, such as "invertebrates" and "vertebrates" are still commonly used today. His student Theophrastus (Greece, 370–285 BC) carried on this tradition, and wrote a classification of some 500 plants called Historia Plantarum. Again, several plant groups currently still recognized can be traced back to Theophrastus, such as Cornus, Crocus, and Narcissus. The next major turn-of-the-millennia era taxonomist came in the form of Pliny the Elder (Rome, 23–79 AD). His elaborate 160-volume work Naturalis Historia described many plants.

Other pre-Linnaean taxonomists[edit]

It was not until c. 1500 years later that taxonomic works became ambitious enough to replace the ancient texts. This is often credited to the development of sophisticated optic lenses, which allowed for the morphology of organisms to be studied in much greater detail. One of the earliest authors to take advantage of this leap in technology was Andrea Cesalpino (Italy, 1519–1603), who is often referred to as "the first taxonomist". His magnum opus De Plantis came out in 1583, and described over 1500 plant species. Two large plant families that he first recognized are still in use today: the Asteraceae and Brassicaceae. Then in the seventeenth century John Ray (England, 1627–1705) wrote many important taxonomic works. Arguably his greatest accomplishment was Methodus Plantarum Nova (1682), where he published over 18,000 plant species. At the time his classifications were perhaps the most complex yet produced by any taxonomist, as he based his taxa on many combined characters. The next major taxonomic works were produced by Joseph Pitton de Tournefort (France, 1656–1708). His work from 1700, Institutiones Rei Herbariae, included over 9000 species in 698 genera, and directly influenced Linnaeus as it was the text he used as a young student.[13]

The Linnaean era[edit]

Title page of Systema Naturae, Leiden, 1735

The Swedish botanist Carl Linnaeus (1707–1778) ushered in a new era of taxonomy. With his major works Systema Naturae 1st Edition in 1735,[15] Species Plantarum in 1753,[16] and Systema Naturae 10th Edition,[17] he revolutionized modern taxonomy. His works implemented a standardized binomial naming system for animal and plant species, which proved to be an elegant solution to a chaotic and disorganized taxonomic literature. As a result the Linnaean system was born, and is still used in essentially the same way today as it was in the eighteenth century. Currently, plant and animal taxonomists regard Linnaeus' work as the "starting point" for valid names (at 1753 and 1758 respectively).[18] Names published before these dates are referred to as "pre-Linnaean", and not considered valid (with the exception of spiders published in Svenska Spindlar). Even taxonomic names published by Linnaeus himself before these dates are considered pre-Linnaean.[13]

The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique.[19]

Phylogenetics and cladistics[edit]

See full articles at Phylogenetics and Cladistics

Today, traditional rank-based biological classifications persist in a structure largely unchanged since the 1700s; however, how the relationships of these taxa are investigated has changed drastically in recent decades. It is now common for biologists to devise a classification based on the results of phylogenetic analysis using DNA sequence data, and taxa are typically required to be clades. Although phylogenetics itself is fundamental to modern-day systematics, its use for the description of new taxa, and for their placement within a classification scheme, is not required.

Application[edit]

Biological taxonomy is a sub-discipline of biology, and is generally practiced by biologists known as "taxonomists", though enthusiastic naturalists are also frequently involved in the publication of new taxa. The work carried out by taxonomists is crucial for the understanding of biology in general. Two fields of applied biology in which taxonomic work is of fundamental importance are the study of biodiversity and conservation.[20] Without a working classification of the organisms in any given area, estimating the amount of diversity present is unrealistic, making informed conservation decisions impossible. As conservation becomes ever more politically important, taxonomic work impacts not only the scientific community, but society as a whole.[12]

Classifying organisms[edit]

Biological classification is a critical component of the taxonomic process. As a result, it informs the user as to what the relatives of the taxon are hypothesized to be. Biological classification uses taxonomic ranks, including, among others (in order from most inclusive to least inclusive): Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.[Note 1]

Taxonomic descriptions[edit]

Type specimen for Nepenthes smilesii, a tropical pitcher plant.

The 'definition' of a taxon is encapsulated by its description and/or its diagnosis. There are no set rules governing the definition of taxa, but the naming and publication of new taxa is governed by sets of rules. In zoology, the nomenclature for the more commonly used ranks (superfamily to subspecies), is regulated by the International Code of Zoological Nomenclature (ICZN Code). In the fields of botany, phycology, and mycology, the naming of taxa is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN).

The initial description of a taxon involves five main requirements:[21]

  1. The taxon must be given a name based on the 26 letters in the Latin alphabet (a binomial for new species, or uninomial for other ranks).
  2. The name must be unique (i.e. not a homonym).
  3. The description must be based on at least one name-bearing type specimen.
  4. It should include statements about appropriate attributes to either describe (define) the taxon, and/or differentiate it from other taxa (the diagnosis, ICZN Code, Article 13.1.1, ICN, Article 38). Both codes deliberately separate defining the content of a taxon (its circumscription) from defining its name.
  5. These first four requirements must be published in a work that is obtainable in numerous identical copies, as a permanent scientific record.

However, often much more information is included, like the geographic range of the taxon, ecological notes, chemistry, behavior, etc. How researchers arrive at their taxa varies; depending on the available data, and resources, methods vary from simple quantitative or qualitative comparisons of striking features, to elaborate computer analyses of large amounts of DNA sequence data.

Phenetics[edit]

Main article: Phenetics

In phenetics, also known as taximetrics, organisms are classified based on overall similarity, regardless of their phylogeny or evolutionary relationships. It results in a measure of evolutionary "distance" between taxa. Phenetic methods have become relatively rare in modern times, largely superseded by cladistic analyses, as phenetic methods do not distinguish plesiomorphic from apomorphic traits. However, certain phenetic methods, such as neighbor joining, have found their way into cladistics, as a reasonable approximation of phylogeny when more advanced methods (such as Bayesian inference) are too computationally expensive.

Databases[edit]

Modern taxonomy uses database technologies to search and catalog classifications and their documentation. While there is no commonly used database, there are comprehensive databases such as the Catalogue of Life, which attempts to list every documented species. The catalogue listed 1.4 million species for all kingdoms as of May 2012, claiming coverage of more than 74% of the estimated 1.9 million species known to modern science.[22]

See also[edit]

Notes[edit]

  1. ^ This ranking system can be remembered by the mnemonic "Do Kings Play Chess On Fine Glass Sets?"

References[edit]

  1. ^ Harper, Douglas. "Taxonomy". Online Etymology Dictionary. Retrieved April 18, 2011. 
  2. ^ a b Judd, W.S., Campbell, C.S., Kellog, E.A., Stevens, P.F., Donoghue, M.J. (2007) Taxonomy. In Plant Systematics – A Phylogenetic Approach, Third Edition. Sinauer Associates, Sunderland.
  3. ^ a b Simpson, Michael G. (2010). "Chapter 1 Plant Systematics: an Overview". Plant Systematics (2nd ed.). Academic Press. ISBN 978-0-12-374380-0. 
  4. ^ Angiosperm Phylogeny Group (2009), "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III", Botanical Journal of the Linnean Society 161 (2): 105–121, doi:10.1111/j.1095-8339.2009.00996.x, retrieved 2010-12-10 
  5. ^ Wilkins, J. S. What is systematics and what is taxonomy?. Available on http://evolvingthoughts.net
  6. ^ Kirk, P.M., Cannon, P.F., Minter, D.W., Stalpers, J.A. eds. (2008) Taxonomy. In Dictionary of the Fungi, 10th edition. CABI, Netherlands.
  7. ^ Walker, P.M.B., ed. (1988). The Wordsworth Dictionary of Science and Technology. W. R. Chambers Ltd. and Cambridge University Press. 
  8. ^ a b Lawrence, E. (2005). Henderson's Dictionary Of Biology. Pearson/Prentice Hall. ISBN 9780131273849. 
  9. ^ Wheeler, Quentin D. (2004). H. C. J. Godfray & S. Knapp, ed. "Taxonomy for the twenty–first century". Philosophical Transactions of the Royal Society 359 (1444): 571–583. doi:10.1098/rstb.2003.1452. PMC 1693342. PMID 15253345.  |chapter= ignored (help)
  10. ^ a b Turrill, W.B. (1938). "The Expansion Of Taxonomy With Special Reference To Spermatophyta". Biological Reviews 13 (4): 342–373. doi:10.1111/j.1469-185X.1938.tb00522.x. 
  11. ^ Steyskal, G.C. (1965). "Trend curves of the rate of species description in zoology". Science 149 (3686): 880–882. doi:10.1126/science.149.3686.880. PMID 17737388. 
  12. ^ a b Knapp, S. (2010). "What's in a name? A history of taxonomy". 
  13. ^ a b c Manktelow, M. (2010) History of Taxonomy. Lecture from Dept. of Systematic Biology, Uppsala University. atbi.eu/summerschool/files/summerschool/Manktelow_Syllabus.pdf
  14. ^ Mayr, E. (1982) The Growth of Biological Thought. Belknap P. of Harvard U.P, Cambridge (Mass.).
  15. ^ Linnaeus, C. (1735) Systema naturae, sive regna tria naturae systematice proposita per classes, ordines, genera, & species. Haak, Leiden
  16. ^ Linnaeus, C. (1753) Species Plantarum. Stockholm, Sweden.
  17. ^ Linnaeus, C. (1758) Systema naturae, sive regna tria naturae systematice proposita per classes, ordines, genera, & species, 10th Edition. Haak, Leiden
  18. ^ Donk, M.A. (1957) Typification and later starting-points. Taxon 6: 245–256.
  19. ^ Singh, Gurcharan (2004). Plant systematics: an integrated approach. Science Publishers, p. 20..
  20. ^ "What is taxonomy?". Natural History Museum London. 
  21. ^ "How can I describe new species?". International Commission on Zoological Nomenclature. 
  22. ^ "About the Catalogue of Life: 2012 Annual Checklist". Catalogue of Life. Integrated Taxonomic Information System (ITIS). Retrieved 22 May 2012. 

External links[edit]

Wikipedia content is licensed under the GFDL License
Powered by YouTube
MASHPEDIA
LEGAL
  • Mashpedia © 2014