HOME

TheInfoList




The tree of life or universal tree of life is a
metaphor A metaphor is a figure of speech A figure of speech or rhetorical figure is a word or phrase that entails an intentional deviation from ordinary language use in order to produce a rhetoric Rhetoric () is the Art (skill), art of ...
, model and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in
Charles Darwin Charles Robert Darwin (; ; 12 February 1809 – 19 April 1882) was an English naturalist Natural history is a domain of inquiry involving organism In biology, an organism () is any organic, life, living system that fu ...

Charles Darwin
's ''
On the Origin of Species ''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''),The book's full original title was ''On the Origin of Species by Me ...
'' (1859). Tree diagrams originated in the
medieval era In the history of Europe, the Middle Ages or medieval period lasted from the 5th to the late 15th century. It began with the fall of the Western Roman Empire The fall of the Western Roman Empire (also called the fall of the Roman E ...
to represent
genealogical relationships
genealogical relationships
.
Phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree (graph theory), tree showing the evolutionary relationships among va ...

Phylogenetic tree
diagrams in the evolutionary sense date back to the mid-nineteenth century. The term
phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram A diagram is a symbolic representation Representation may refer to: Law a ...

phylogeny
for the evolutionary relationships of species through time was coined by
Ernst Haeckel Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that stud ...

Ernst Haeckel
, who went further than
Darwin Darwin most often refers to: * Charles Darwin (1809–1882), English naturalist and writer, best known as the originator of the theory of biological evolution by natural selection * Darwin, Northern Territory, a capital city in Australia * Darwin ( ...

Darwin
in proposing
phylogenic In biology, phylogenetics (from Greek language, Greek wikt:φυλή, φυλή/wikt:φῦλον, φῦλον () "tribe, clan, race", and wikt:γενετικός, γενετικός () "origin, source, birth") is a part of systematics that addresse ...

phylogenic
histories of life. In contemporary usage, ''tree of life'' refers to the compilation of comprehensive phylogenetic databases rooted at the
last universal common ancestor The last universal common ancestor or last universal cellular ancestor (LUCA), also called the last universal ancestor (LUA), is the most recent population of organisms from which all organisms now living on Earth have a common descent—the mos ...
of life on Earth. Two public databases for the tree of life are ''TimeTree'', for phylogeny and divergence times, and the '' Open Tree of Life'', for phylogeny.


Early trees in natural classification

Although tree-like diagrams have long been used to organize knowledge, and although branching diagrams known as ''claves'' ("keys") were omnipresent in eighteenth-century
natural history Natural history is a domain of inquiry involving organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecul ...

natural history
, it appears that the earliest tree diagram of natural order was the "Arbre botanique" (Botanical Tree) of the French schoolteacher and Catholic priest
Augustin Augier François Augustin Marie Augier de Favas (15 December 1758 – 29 January 1825), also known as Augustin Augier, was a French schoolteacher, a Catholic The Catholic Church, also known as the Roman Catholic Church, is the List of Christian d ...

Augustin Augier
, first published in 1801. Yet, although Augier discussed his tree in distinctly genealogical terms, and although his design clearly mimicked the visual conventions of a contemporary family tree, his tree did not include any evolutionary or temporal aspect. Consistent with Augier's priestly vocation, the Botanical Tree showed rather the perfect order of nature as instituted by God at the moment of Creation. In 1809, Augier's more famous compatriot
Jean-Baptiste Lamarck Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), often known simply as Lamarck (; ), was a French naturalist Natural history is a domain of inquiry involving organism In biology, ...

Jean-Baptiste Lamarck
(1744–1829), who was acquainted with Augier's "Botanical Tree", included a branching diagram of animal species in his '' Philosophie zoologique''. Unlike Augier, however, Lamarck did not discuss his diagram in terms of a genealogy or a tree, but instead named it a ''tableau'' ("table"). Lamarck believed in the transmutation of life forms, but he did not believe in common descent; instead he believed that life developed in parallel lineages advancing from more simple to more complex. In 1840, the American geologist
Edward Hitchcock Edward Hitchcock (May 24, 1793 – February 27, 1864) was an American geologist and the third President of Amherst College (1845–1854). Life Born to poor parents, he attended newly founded Deerfield Academy, where he was later principal, fr ...

Edward Hitchcock
(1793–1864) published the first tree-like paleontology chart in his ''Elementary Geology''. On the vertical axis are paleontological periods. Hitchcock made a separate tree for plants (left) and animals (right). The plant and the animal tree are not connected at the bottom of the chart. Furthermore, each tree starts with multiple origins. Hitchcock's tree was more realistic than Darwin's 1859 theoretical tree (see below) because Hitchcock used real names in his trees. It is also true that Hitchcock's trees were branching trees. However, they were not evolutionary trees, because Hitchcock believed that a deity was the agent of change. That was an important difference with Darwin. The first edition of Robert Chambers' ''
Vestiges of the Natural History of Creation ''Vestiges of the Natural History of Creation'' is an 1844 work of speculative natural history Natural history is a domain of inquiry involving organisms, including animals, fungus, fungi, and plants, in their natural environment, leaning mor ...
'', which was published anonymously in 1844 in England, contained a tree-like diagram in the chapter "Hypothesis of the development of the vegetable and animal kingdoms". It shows a model of embryological development where fish (F), reptiles (R), and birds (B) represent branches from a path leading to mammals (M). In the text this branching tree idea is tentatively applied to the history of life on earth: "there may be branching", but the branching diagram is not displayed again specifically for this purpose. However, the image of a branching tree could easily have inspired others to use it explicitly as a representation of the history of life on earth. In 1858, a year before Darwin's ''Origin'', the paleontologist
Heinrich Georg Bronn Heinrich Georg Bronn Heinrich Georg Bronn (3 March 1800 – 5 July 1862) was a German geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes the Earth and other terrestrial planets, as well as t ...

Heinrich Georg Bronn
(1800–1862) published a hypothetical tree labeled with letters. Although not a creationist, Bronn did not propose a mechanism of change.


Theory


Darwin

Charles Darwin Charles Robert Darwin (; ; 12 February 1809 – 19 April 1882) was an English naturalist Natural history is a domain of inquiry involving organism In biology, an organism () is any organic, life, living system that fu ...

Charles Darwin
(1809–1882) used the metaphor of a "tree of life" to conceptualize his theory of evolution. In ''
On the Origin of Species ''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''),The book's full original title was ''On the Origin of Species by Me ...
'' (1859) he presented an abstract diagram of a theoretical tree of life for species of an unnamed large
genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscribing) and classifying gr ...
(see figure). On the horizontal base line hypothetical species within this genus are labelled A – L and are spaced irregularly to indicate how distinct they are from each other, and are above broken lines at various angles suggesting that they have diverged from one or more common ancestors. On the vertical axis divisions labelled I – XIV each represent a thousand generations. From A, diverging lines show branching descent producing new varieties, some of which become extinct, so that after ten thousand generations descendants of A have become distinct new varieties or even sub-species a10, f10, and m10. Similarly, the descendants of I have diversified to become the new varieties w10 and z10. The process is extrapolated for a further four thousand generations so that the descendants of A and I become fourteen new species labelled a14 to z14. While F has continued for fourteen thousand generations relatively unchanged, species B,C,D,E,G,H,K and L have gone extinct. In Darwin's own words: "Thus the small differences distinguishing varieties of the same species, will steadily tend to increase till they come to equal the greater differences between species of the same genus, or even of distinct genera.". This is a branching pattern with no names given to species, unlike the more linear tree Ernst Haeckel made years later (figure below) which includes the names of species and shows a more linear development from "lower" to "higher" species. In his summary to the section, Darwin put his concept in terms of the metaphor of the tree of life: The meaning and importance of Darwin's use of the tree of life metaphor have been extensively discussed by scientists and scholars.
Stephen Jay Gould Stephen Jay Gould (; September 10, 1941 – May 20, 2002) was an American Paleontology, paleontologist, Evolutionary biology, evolutionary biologist, and History of science, historian of science. He was one of the most influential and widely read ...
, for one, has argued that Darwin placed the famous passage quoted above "at a crucial spot in his text", where it marked the conclusion of his argument for natural selection, illustrating both the interconnectedness by descent of organisms as well as their success and failure in the history of life. David Penny has written that Darwin did not use the tree of life to describe the relationship between groups of organisms, but to suggest that, as with branches in a living tree, lineages of species competed with and supplanted one another. Petter Hellström has argued that Darwin consciously named his tree after the biblical
Tree of Life #REDIRECT Tree of life#REDIRECT Tree of life The tree of life is a fundamental widespread mytheme or archetype in many of the world's mythology, mythologies, religion, religious and philosophy, philosophical traditions. It is closely related ...
, as described in
Genesis Genesis may refer to: Literature and comics * Genesis (DC Comics), a 1997 DC Comics crossover * Genesis (Marvel Comics), a Marvel Comics villain * Genesis, a fictional character from the ''Preacher (comics), Preacher'' comic-book series * ''Genes ...
, thus relating his theory to the religious tradition.


Haeckel

File:Ernst Haeckel - Tree of Life.jpg,
Haeckel Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studie ...

Haeckel
's ''Stammbaum der Primaten'' (1860s) File:Haeckel arbol bn.png, Haeckel's tree of life in ''Generelle Morphologie der Organismen'' (1866) File:Tree of life by Haeckel.jpg, The tree of life as seen by Haeckel in ''The Evolution of Man'' (1879)
Ernst Haeckel Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that stud ...

Ernst Haeckel
(1834–1919) constructed several trees of life. His first sketch (in the 1860s) of his famous tree of life shows "''Pithecanthropus alalus''" as the ancestor of ''Homo sapiens''. His 1866 tree of life from ''Generelle Morphologie der Organismen'' shows three kingdoms: Plantae, Protista and Animalia. His 1879 'Pedigree of Man' was published in ''The Evolution of Man''.


Proposals for top levels

''Various authors have proposed different schemes for the top level of the tree of cellular life.'' ''Some authors have added a classification for
non-cellular life Non-cellular life, or acellular life is life Life is a characteristic that distinguishes physical entities A bubble of exhaled gas in water In common usage and classical mechanics, a physical object or physical body (or simply an ob ...
.''


Developments since 1990

In 1990,
Carl Woese Carl Richard Woese (; July 15, 1928 – December 30, 2012) was an American microbiologist A microbiologist (from Greek ) is a scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an B ...

Carl Woese
,
Otto Kandler Otto Kandler (23 October 1920 in Deggendorf Deggendorf () is a town in Bavaria, Germany, capital of the Deggendorf (district), Deggendorf district. It is located on the left bank approximately in the middle between the Danube cities of Regensburg ...
and Mark Wheelis proposed a "tree of life" consisting of three lines of descent for which they introduced the term
domain Domain may refer to: Mathematics *Domain of a function In mathematics, the domain of a Function (mathematics), function is the Set (mathematics), set of inputs accepted by the function. It is sometimes denoted by \operatorname(f), where is th ...
as the highest rank of classification. They also suggested the terms
bacteria Bacteria (; common noun bacteria, singular bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typ ...

bacteria
,
archaea Archaea ( ; singular archaeon ) constitute a domain Domain may refer to: Mathematics *Domain of a function, the set of input values for which the (total) function is defined **Domain of definition of a partial function **Natural domain of a pa ...

archaea
and
eukaryota Eukaryotes () are organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interact ...

eukaryota
for the three domains. The model of a tree is still considered valid for
eukaryotic Eukaryotes () are organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interact ...
life forms. , research into the earliest branches of the eukaryote tree has suggested a tree with either four or two supergroups. There does not yet appear to be a consensus; in a review article, Roger and Simpson conclude that "with the current pace of change in our understanding of the eukaryote tree of life, we should proceed with caution." In 2015, the first draft of the Open Tree of Life was published, in which information from nearly 500 previously published trees was combined into a single online database, free to browse and download. In 2016, a new tree of life, summarizing the
evolution Evolution is change in the heritable Heredity, also called inheritance or biological inheritance, is the passing on of Phenotypic trait, traits from parents to their offspring; either through asexual reproduction or sexual reproduction, ...

evolution
of all known
life forms Life form (also spelled life-form or lifeform) is an entity that is living, such as plants (flora) and animals (fauna). It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, are ex ...

life forms
, was published, illustrating the latest
gene In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mecha ...

gene
tic findings that the branches were mainly composed of
bacteria Bacteria (; common noun bacteria, singular bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typ ...

bacteria
. The new study incorporated over a thousand newly discovered
bacteria Bacteria (; common noun bacteria, singular bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typ ...

bacteria
and
archaea Archaea ( ; singular archaeon ) constitute a domain Domain may refer to: Mathematics *Domain of a function, the set of input values for which the (total) function is defined **Domain of definition of a partial function **Natural domain of a pa ...

archaea
.


Horizontal gene transfer

The
prokaryotes A prokaryote () is a single-celled organism A unicellular organism, also known as a single-celled organism, is an organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contig ...

prokaryotes
(the two domains of
bacteria Bacteria (; common noun bacteria, singular bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typ ...

bacteria
and
archaea Archaea ( ; singular archaeon ) constitute a domain Domain may refer to: Mathematics *Domain of a function, the set of input values for which the (total) function is defined **Domain of definition of a partial function **Natural domain of a pa ...

archaea
) and certain animals such as s have the ability to transfer genetic information between unrelated organisms through
horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular A unicellular organism, also known as a single-celled organism, is an organism In biology, an organism (from Ancient G ...
. Recombination, gene loss, duplication, and gene creation are a few of the processes by which genes can be transferred within and between bacterial and archaeal species, causing variation that is not due to vertical transfer. There is emerging evidence of horizontal gene transfer within the prokaryotes at the single and multicell level, so the tree of life does not explain the full complexity of the situation in the prokaryotes.


See also

*
Bacterial phyla Bacterial phyla constitute the major lineages of the domain ''Bacteria Bacteria (; common noun bacteria, singular bacterium) are a type of Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic m ...
*
Cladistics Cladistics (; ) is an approach to biological classification In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular ...

Cladistics
*
Common descent Common descent is a concept in evolutionary biology Evolutionary biology is the subfield of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, c ...
*
Coral of lifeThe coral of life is a metaphor or a mathematical model useful to illustrate evolution of life or phylogeny at various levels of resolution, including individual organisms, populations, species and large taxonomic groups. Its use in biology resolves ...
*
History of evolutionary thought Evolutionary thought, the recognition that species change over time and the perceived understanding of how such processes work, has roots in antiquity—in the ideas of the Ancient Greece, ancient Greeks, Ancient Rome, Romans, and Ancient China ...
*
Holism Holism (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately ...
*
Horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular A unicellular organism, also known as a single-celled organism, is an organism In biology, an organism (from Ancient G ...
*
Last universal common ancestor The last universal common ancestor or last universal cellular ancestor (LUCA), also called the last universal ancestor (LUA), is the most recent population of organisms from which all organisms now living on Earth have a common descent—the mos ...
*
Mass extinctions An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity Biodiversity is the biological variety and Genetic variability, variability of life, life on Earth. Biodiversity is ...
*
Nomenclature codes Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classifica ...
*
Phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree (graph theory), tree showing the evolutionary relationships among va ...

Phylogenetic tree
*
Symbiogenesis Symbiogenesis, endosymbiotic theory, or serial endosymbiotic theory is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibly oth ...

Symbiogenesis
*
Taxonomic rank In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in a Taxonomy (biology), taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family (biology), family, order (biology), order, ...
*
Tree of Life Web Project In botany Botany, also called , plant biology or phytology, is the science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method, builds and Taxonomy (general), organiz ...


References


Further reading

* * *


External links


Tree of Life Web Project
- explore complete phylogenetic tree interactively
Tree of Life Evolution
Links species on Earth through a shared evolutionary history
Science journal issue
- Issue devoted to the tree of life.
The Tree of Life
by Garrett Neske,
The Wolfram Demonstrations Project The Wolfram Demonstrations Project is an organized, open-source collection of small (or medium-size) interactive programs called Demonstrations, which are meant to visually and interactively represent ideas from a range of fields. It is hoste ...
: "presents an interactive tree of life that allows you to explore the relationships between many different kinds of organisms by allowing you to select an organism and visualize the clade to which it belongs."
The Green Tree of Life
-
Hyperbolic treeA hyperbolic tree (often shortened as hypertree) is an information visualization and graph drawing Graph drawing is an area of mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory) ...
University of California/Jepson Herbaria
NCBI's taxonomy database common tree
{{DEFAULTSORT:Tree Of Life (Biology) History of biology