Systematics

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"Systematic biology" redirects here. Systematics_sentence_0

For the journal, see Systematic Biology. Systematics_sentence_1

For other uses, see Systematics (disambiguation). Systematics_sentence_2

Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Systematics_sentence_3

Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic trees, phylogenies). Systematics_sentence_4

Phylogenies have two components: branching order (showing group relationships) and branch length (showing amount of evolution). Systematics_sentence_5

Phylogenetic trees of species and higher taxa are used to study the evolution of traits (e.g., anatomical or molecular characteristics) and the distribution of organisms (biogeography). Systematics_sentence_6

Systematics, in other words, is used to understand the evolutionary history of life on Earth. Systematics_sentence_7

The word systematics is derived from Latin word `systema', which means systematic arrangement of organisms. Systematics_sentence_8

Carl Linnaeus used 'Systema Naturae' as the title of his book. Systematics_sentence_9

Branches and applications Systematics_section_0

In the study of biological systematics, researchers use the different branches to further understand the relationships between differing organisms. Systematics_sentence_10

These branches are used to determine the applications and uses for modern day systematics. Systematics_sentence_11

Biological systematics classifies species by using three specific branches. Systematics_sentence_12

Numerical systematics, or biometry, uses biological statistics to identify and classify animals. Systematics_sentence_13

Biochemical systematics classifies and identifies animals based on the analysis of the material that makes up the living part of a cell—such as the nucleus, organelles, and cytoplasm. Systematics_sentence_14

Experimental systematics identifies and classifies animals based on the evolutionary units that comprise a species, as well as their importance in evolution itself. Systematics_sentence_15

Factors such as mutations, genetic divergence, and hybridization all are considered evolutionary units. Systematics_sentence_16

With the specific branches, researchers are able to determine the applications and uses for modern-day systematics. Systematics_sentence_17

These applications include: Systematics_sentence_18

Systematics_unordered_list_0

  • Studying the diversity of organisms and the differentiation between extinct and living creatures. Biologists study the well-understood relationships by making many different diagrams and "trees" (cladograms, phylogenetic trees, phylogenies, etc.).Systematics_item_0_0
  • Including the scientific names of organisms, species descriptions and overviews, taxonomic orders, and classifications of evolutionary and organism histories.Systematics_item_0_1
  • Explaining the biodiversity of the planet and its organisms. The systematic study is that of conservation.Systematics_item_0_2
  • Manipulating and controlling the natural world. This includes the practice of 'biological control', the intentional introduction of natural predators and disease.Systematics_item_0_3

Definition and relation with taxonomy Systematics_section_1

John Lindley provided an early definition of systematics in 1830, although he wrote of "systematic botany" rather than using the term "systematics". Systematics_sentence_19

In 1970 Michener et al. Systematics_sentence_20

defined "systematic biology" and "taxonomy" (terms that are often confused and used interchangeably) in relationship to one another as follows: Systematics_sentence_21

The term "taxonomy" was coined by Augustin Pyramus de Candolle while the term "systematic" was coined by Carl Linnaeus the father of taxonomy. Systematics_sentence_22

Taxonomy, systematic biology, systematics, biosystematics, scientific classification, biological classification, phylogenetics: At various times in history, all these words have had overlapping, related meanings. Systematics_sentence_23

However, in modern usage, they can all be considered synonyms of each other. Systematics_sentence_24

For example, Webster's 9th New Collegiate Dictionary of 1987 treats "classification", "taxonomy", and "systematics" as synonyms. Systematics_sentence_25

According to this work, the terms originated in 1790, c. 1828, and in 1888 respectively. Systematics_sentence_26

Some claim systematics alone deals specifically with relationships through time, and that it can be synonymous with phylogenetics, broadly dealing with the inferred hierarchy of organisms. Systematics_sentence_27

This means it would be a subset of taxonomy as it is sometimes regarded, but the inverse is claimed by others. Systematics_sentence_28

Europeans tend to use the terms "systematics" and "biosystematics" for the study of biodiversity as a whole, whereas North Americans tend to use "taxonomy" more frequently. Systematics_sentence_29

However, taxonomy, and in particular alpha taxonomy, is more specifically the identification, description, and naming (i.e. nomenclature) of organisms, while "classification" focuses on placing organisms within hierarchical groups that show their relationships to other organisms. Systematics_sentence_30

All of these biological disciplines can deal with both extinct and extant organisms. Systematics_sentence_31

Systematics uses taxonomy as a primary tool in understanding, as nothing about an organism's relationships with other living things can be understood without it first being properly studied and described in sufficient detail to identify and classify it correctly. Systematics_sentence_32

Scientific classifications are aids in recording and reporting information to other scientists and to laymen. Systematics_sentence_33

The systematist, a scientist who specializes in systematics, must, therefore, be able to use existing classification systems, or at least know them well enough to skilfully justify not using them. Systematics_sentence_34

Phenetics was an attempt to determine the relationships of organisms through a measure of overall similarity, making no distinction between plesiomorphies (shared ancestral traits) and apomorphies (derived traits). Systematics_sentence_35

From the late-20th century onwards, it was superseded by cladistics, which rejects plesiomorphies in attempting to resolve the phylogeny of Earth's various organisms through time. Systematics_sentence_36

Today's systematists generally make extensive use of molecular biology and of computer programs to study organisms. Systematics_sentence_37

Taxonomic characters Systematics_section_2

Taxonomic characters are the taxonomic attributes that can be used to provide the evidence from which relationships (the phylogeny) between taxa are inferred. Systematics_sentence_38

Kinds of taxonomic characters include: Systematics_sentence_39

See also Systematics_section_3

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Systematics.