The innocent prisoner's dilemma, or parole deal, is a detrimental effect of a legal system in which admission of guilt can result in reduced sentences or early parole.
When an innocent person is wrongly convicted of a crime, legal systems
which need the individual to admit guilt — as, for example, a
prerequisite step leading to parole — punish an innocent person for
their integrity, and reward a person lacking in integrity. There have
been cases where innocent prisoners were given the choice between
freedom, in exchange for claiming guilt, and remaining imprisoned and
telling the truth. Individuals have died in prison rather than admit to crimes that they did not commit, including in the face of a plausible chance at release.
United States law professor Daniel Medwed says convicts who go
before a parole board maintaining their innocence are caught in a catch-22 that he calls "the innocent prisoner’s dilemma". A false admission of guilt and remorse by an innocent person at a
parole hearing may prevent a later investigation proving their
innocence.
Detriment to individuals
In the United Kingdom
Michael Naughton, founder of the Innocence Network
UK (INUK), says work carried out by the INUK includes research and
public awareness on wrongful convictions, which can affect policy
reforms. Most important is the development of a system to assess
prisoners maintaining innocence, to distinguish potentially innocent
prisoners from the prisoners who claim innocence for other reasons like
"ignorance, misunderstanding or disagreement with criminal law; to
protect another person or group from criminal conviction; or on 'abuse
of process' or technical grounds in the hope of achieving an appeal." The system, he says, is being adopted by the prison parole board and
prison service for prisoners serving "indeterminate sentences (where the
prisoner has no release date and does not get out until a parole board
decides he or she is no longer a risk to the public). Previously, such
prisoners were treated as 'deniers' with no account taken of the various
reasons for maintaining innocence, nor the fact that some may actually
be innocent." Those prisoners are unable to achieve parole unless they
undertake offence-behaviour courses that require the admission of guilt
as a prerequisite. This was represented in the Porridge episode Pardon Me. However, in recent years, this has diminished in significance; at the time Simon Hall
ended his denials to murder in 2012, the Ministry of Justice denied
that this would have any impact on his tariff, and his last online
posting had been concerned with being released from prison in spite of
his denials.
Linda Cook was murdered in Portsmouth on 9 December 1986. Michael Shirley, an 18-year-old Royal Navy sailor, was wrongly convicted of the crime and sentenced to life imprisonment. After serving the minimum 15 years, Shirley would have been released from prison had he confessed to the killing to the parole board,
but he refused to do so and said: "I would have died in prison rather
than admit something I didn't do. I was prepared to stay in forever if
necessary to prove my innocence."Shirley's conviction was eventually quashed by the Court of Appeal in 2003, on the basis of exculpatory DNA evidence.
Stephen Downing
was a 17-year-old council worker convicted and imprisoned in 1974 for
the murder of a 32-year-old legal secretary, Wendy Sewell. His
conviction was overturned in 2002 after Downing had served 27 years in
prison. The case is thought to be the longest miscarriage of justice in
British legal history, and it attracted worldwide media attention. The case was featured in the 2004 BBC drama In Denial of Murder. Downing claimed that had he falsely confessed he would have been
released over a decade earlier. Because he did not admit to the crime,
he was classified as "IDOM" (In Denial of Murder) and ineligible for
parole under English law.
Andrew Malkinson was wrongfully convicted of the rape of a 33-year-old woman in Salford, Greater Manchester, in 2003 and imprisoned. He would have been eligible for release after 6½ years of imprisonment,
but his refusal to wrongly confess meant that authorities refused to
grant parole. He was released after 17 years in prison, and was declared innocent by the Court of Appeal in July 2023. The case has been academically studied as a severe miscarriage of justice.
In the United States
In the United States the reality of a person being innocent, called "actual innocence", is not sufficient reason for the justice system to release a prisoner. Once a verdict has been made, it is rare for a court to reconsider
evidence of innocence that could have been presented at the time of the
original trial. Decisions by the State Board of Pardons and Paroles
regarding its treatment of prisoners who may be actually innocent have
been criticized by the international community.
Herbert Murray, who was convicted of murder in 1979, said, "When
the judge asked me did I have anything to say, I couldn't say, because
tears were coming down and I couldn’t communicate. I couldn't turn
around and tell the family that they got the wrong man." The judge said
he believed the defense's alibi witnesses; however, the judge was
required by law to respect the jury's decision. After Murray had been
locked up for 19 years, his parole officer said "Nineteen years is a
long time. [....] But you’re no closer to the rehabilitative process
than when you first walked into prison. The first step in that process
is the internalization of guilt. You need to do some serious
introspection, Mr. Murray, and come to grips with your behavior." Murray
agreed with the parole officer but maintained his innocence: "I agree!
But again, I just didn't do it."
In a news interview, Murray says he went before a parole board
four times, maintaining his innocence until the fifth time: "I said what
the hell, let me tell these people what they want to hear." He admitted
to the parole board that he committed the crime and was taking
responsibility. "I felt like I sold my soul to the devil. Because
before, I had that strength, because I stood on the truth. [...] I
became so desperate to get out, I had to say something. I had to say
something because what I said before didn't work." His parole was
denied. After 29 years in prison, Medwed's Second Look clinic,
a group dedicated to the release of innocent prisoners, assisted
lawyers in his eighth parole board hearing which was successful,
releasing him onto indefinite parole. However, overturning the original
conviction would be hampered by his admissions of guilt at his parole
hearings.
Timothy Brian Cole (1960–99) was an African American military veteran and a student wrongly convicted of raping
a fellow student in 1985. Cole was convicted by a jury of rape,
primarily based on the testimony of the victim, Michele Mallin. He was
sentenced to 25 years in prison. While incarcerated, Cole was offered parole if he would admit guilt, but he refused. "His greatest wish was to be exonerated and completely vindicated", his
mother stated in a press interview. Cole died after serving 14 years in
prison.
Another man, Jerry Wayne Johnson, confessed to the rape in 1995.
Further, Mallin later admitted that she was mistaken as to the identity
of her attacker. She stated that investigators botched the gathering of
evidence and withheld information from her, causing her to believe that
Cole was the perpetrator. Mallin told police that the rapist smoked during the rape. However, Cole never smoked because of his severe asthma. DNA evidence later showed him to be innocent. Cole died in prison on December 2, 1999; ten years later, a district
court judge announced "to a 100 percent moral, factual and legal
certainty" that Timothy Cole did not commit the rape. He was
posthumously pardoned.
The dilemma can occur even before conviction. Kalief Browder
was arrested in May 2010 for allegedly stealing a backpack. He spent
the next three years on Rikers Island awaiting trial, much of it in
solitary. During court appearances, prosecutors routinely asked for a
short delay which would turn into a much lengthier wait. At times,
Browder was offered plea bargains, and at one point, he was encouraged
to plead guilty to misdemeanors, for which he would be sentenced to time
already served and released. When he refused the plea deal, insisting
on his innocence, the judge noted "If you go to trial and lose, you
could get up to fifteen [years]." Eventually, in May 2013, the case was
dismissed because prosecutors had lost contact with the only witness
they had to the alleged crime.
Detriment to society
A
British conference in 2011 concluded that "Denial is not a valid
measure of risk. In fact, research has shown that prisoners who openly
admit to their crimes have the highest risk of re-offending."
In 2011, Michael Naughton suggested the focus on new evidence by the Criminal Cases Review Commission,
rather than an examination of serious problems with evidence at
original trials, meant in many cases “that the dangerous criminals who
committed these crimes remain at liberty with the potential to commit
further serious crimes.”
Robert A. Forde cited two studies at the conference. One, a
ten-year study of 180 sex offenders by Harkins, Beech and Goodwill found
prisoners who claimed to be innocent were the least likely to be
re-convicted, and that those who 'admitted everything', claiming to be
guilty, were most likely to re-offend. He also told the conference
research by Hanson et al. in 2002, the denial by the prisoner of their offences had no bearing on their likelihood of re-offending.
Innocence Project, Inc. is a 501(c)(3) nonprofit legal organization that works to exonerate the wrongly convicted through DNA testing and other forms of post-conviction relief, as well as advocates for criminal justice reform to prevent future injustice. The group cites various studies estimating that in the United States between 1% and 10% of all prisoners are innocent. The Innocence Project was founded in 1992 by Barry Scheck and Peter Neufeld, who gained national attention in the mid-1990s as part of the "Dream Team" of lawyers who formed part of the defense in the O. J. Simpson murder case.
As of 2021, the Innocence Project has successfully overturned more than 300 convictions through DNA-based exonerations.In 2021, the Innocence Project received the biennial Milton Friedman Prize for Advancing Liberty by Cato Institute, awarded in recognition and gratitude for its work to ensure liberty and justice for all. In March 2022, The Innocence Project won two Webby Awards for its Happiest Moments video, winning the Best Humanitarian & Services campaign in both the brand and non-profit categories. Happiest Moments was the organization's first public service announcement, premiering in June 2021 and produced by Hayden5.
Founding
Logo used from 1992 to 2018
The Innocence Project was established in the wake of a study by the U.S. Department of Justice and U.S. Senate, in conjunction with Yeshiva University's Benjamin N. Cardozo School of Law, which claimed that incorrect identification by eyewitnesses was a factor in over 70% of wrongful convictions.The Innocence Project was founded in 1992 by Scheck and Neufeld as part of a law clinic at Cardozo. It became an independent 501(c)(3)nonprofit organization on January 28, 2003, but it maintains institutional connections with Cardozo.Madeline deLone was the executive director from 2004 until 2020, succeeded by Christina Swarns, who argues before the United States Supreme Court before joining the group, on September 8, 2020.
The Innocence Project is the headquarters of the Innocence Network, a group of nearly 70 independent innocence organizations worldwide. One such example exists in the Republic of Ireland where in 2009 a project was set up at Griffith College Dublin.
Mission
The
Innocence Project's mission is "to free the staggering number of
innocent people who remain incarcerated, and to bring reform to the
system responsible for their unjust imprisonment."
The Innocence Project focuses exclusively on post-conviction appeals in which DNA evidence is available to be tested or retested. DNA testing is possible in 5–10% of criminal cases. Other members of the Innocence Network also help to exonerate those in whose cases DNA testing is not possible.
In addition to working on behalf of those who may have been
wrongfully convicted of crimes throughout the United States, those
working for the Innocence Project perform research and advocacy related
to the causes of wrongful convictions.
Some of the Innocence Project's successes have resulted in releasing people from death row.
The successes of the project have fueled American opposition to the
death penalty and have likely been a factor in the decision by some
American states to institute moratoria on criminal executions.
In District Attorney's Office v. Osborne (2009), U.S. Supreme Court Chief Justice Roberts
wrote that post-conviction challenge "poses questions to our criminal
justice systems and our traditional notions of finality better left to
elected officials than federal judges." In the opinion, another justice
wrote that forensic science
has "serious deficiencies." Roberts also said that post-conviction DNA
testing risks "unnecessarily overthrowing the established system of
criminal justice." Law professor Kevin Jon Heller wrote: "It might lead to a reasonably accurate one."
As of June 2018, the Innocence Project's funding sources include
55% from individual contributions, 16% from foundations, 16% from
events, 8% from investments, and 5% from corporations, Yeshiva
University, and other sources.
Work
The Innocence Project originated in New York City but accepts cases from other parts of the country. The majority of clients helped are of low socio-economic status and
have used all possible legal options for justice. Many clients hope that
DNA evidence will prove their innocence, as the emergence of DNA
testing allows those who have been wrongly convicted of crimes to
challenge their cases. The Innocence Project also works with the local,
state and federal levels of law enforcement, legislators, and other
programs to prevent further wrongful convictions.
All potential clients go through an extensive screening process
to determine whether or not they are likely to be innocent. If they pass
the process, the Innocence Project takes up their case, resources
permitting. About 2,400 prisoners write to the Innocence Project
annually, and at any given time the Innocence Project is evaluating
6,000 to 8,000 potential cases. In addition to their co-directors and a
managing attorney, the Innocence Project has six full-time staff
attorneys and nearly 300 active cases.
In almost half of the cases that the Innocence Project takes on,
the clients' guilt is reconfirmed by DNA testing. Of all the cases taken
on by the Innocence Project so far, about 43% of clients were proven
innocent, 42% were confirmed guilty, and evidence was inconclusive and
not probative in 15% of cases. In about 40% of all DNA exoneration
cases, law enforcement officials identified the actual perpetrator based
on the same DNA test results that led to an exoneration. Overall, the Innocence Project's DNA exonerations identified several
contributors of wrongful convictions, including mistaken eyewitness
identifications, invalid forensic science, false confessions, informants
who lied, and government misconduct.
Overturned convictions
As of January 2022,
375 people previously convicted of serious crimes in the United States
had been exonerated by DNA testing since 1989, 21 of whom had been
sentenced to death. Almost all (99%) of the wrongful convictions involved male defendants with minority groups making up approximately 70% (61% African American and 8% Latino). The National Registry of Exonerations lists 2,939 convicted defendants
who were exonerated through DNA and non-DNA evidence from January, 1989
through January, 2022 with more than 25,600 years imprisoned.
According to a study published in 2014, at least 4.1% of persons
overall sentenced to death from 1973 to 2004 are probably innocent. The following are some examples of exonerations they helped bring about:
Steven Avery was exonerated in 2003 after serving 18 years in prison for sexual assault.Following his release, he was convicted of murder.
Cornelius Dupree was convicted of sexual assault and robbery in 1980 and was exonerated in 2011 by the Innocence Project through DNA evidence.
Douglas Echols and Samuel Scott were convicted in 1987 of sexual assault and robbery, and exonerated in 2002 by DNA evidence by the Innocence Project.
Clarence Elkins was convicted in 1999 for rape and murder, and exonerated by DNA evidence in 2005; defended by Ohio Innocence Project.
Ryan Ferguson
was convicted in 2005 for a 2001 murder, and exonerated in 2013 because
the prosecution withheld exculpatory evidence and the witnesses who
testified against him recanted their testimony; defended by Missouri
Innocence Project.
Glenn Ford was exonerated in 2014 in the murder of Isadore Newman. Ford, an African American, had been convicted by an all-white jury without any physical evidence linking him to the crime and with testimony withheld. He served 30 years on death row in Angola Prison before his release.
Darryl Hunt was exonerated in 2004 after serving 19+1⁄2 years in prison of a life sentence for the rape and murder of a newspaper copy editor, Deborah Sykes.
Michael Morton
was convicted of murder in 1987, spent over 24 years in prison, and
exonerated through DNA and withholding of evidence in 2011 with help
from the Innocence Project. In 2013 his prosecutor was convicted of
withholding evidence, agreed to disbarment, and spent 4 days in jail.
James Calvin Tillman was exonerated in 2007 after an investigation begun by the Innocence Project, and after serving 16+1⁄2 years in prison for a rape he did not commit. His sentence was 45 years.
Archie Williams
was convicted in 1983 of sexual assault and sentenced to life without
the possibility of parole, but was exonerated in 2019 due to DNA
evidence after over three decades in prison.
Ken Wyniemko was convicted in 1994 of sexual assault, and exonerated in 2003 through DNA evidence by the Innocence Project.
Michael Sutton and Kenny Phillips went out for Phillips' birthday in
May 2006, they were wrongfully arrested and incarcerated for 15 years.
In 2023, their attempted murder convictions were overturned and the University of Akron granted them full scholarships to earn their college degrees.
Leonard Mack was exonerated of rape and gun charges after 47 years due to DNA evidence. Mack's wrongful conviction was the longest to be vacated due to advanced DNA testing.
Perry Lott served 30 years in prison for rape and burglary charges before being cleared after DNA testing.
Innocence Network
The Innocence Project is a founding member of the Innocence Network, a coalition of independent organizations and advocates, including law schools, journalism schools, and public defense offices that collaborate to help convicted felons prove their innocence.As of 2021,
there were 68 organizations in the network, operating in all 50 US
states and 12 other countries, and had helped exonerate 625 people.
In South Africa, the Wits Justice Project investigates South
African incarcerations. In partnership with the Wits Law Clinic, the
Julia Mashele Trust, the Legal Resources Centre
(LRC), the Open Democracy Advice Centre (ODAC), the US Innocence
Project, and the Justice Project investigate individual cases of
prisoners wrongly convicted or awaiting trial.
In popular culture
Film
After Innocence (2005) is a documentary featuring the stories of eight wrongfully convicted men who were exonerated by the Innocence Project.
Conviction (2010) is a film about the exoneration of Kenneth Waters, who was a client of the Innocence Project. Hilary Swank plays Waters' sister Betty Anne, who went to college and law school to fight for his freedom, and Sam Rockwell plays Waters. Barry Scheck is portrayed by Peter Gallagher.
Serial
in its first season referenced the Innocence Project in episode 7 when
Deirdre Enright, director of investigation for the Innocence Project at
the University of Virginia School of Law, and a team of law students analyzed the case against Adnan Syed.
Television
Castle,
an American television series, in the episode "Like Father, Like
Daughter" (season 6, episode 7), mentioned the Innocence Project, as
well as Frank Henson who was wrongfully convicted in 1998 of the death
of Kimberly Tolbert.
The Innocence Project, a BBC One drama series that aired from 2006 to 2007, is based on a UK version of the organization.
The Innocence Project was discussed in season 2, episode 9 of The Good Wife,
"Nine Hours" (December 14, 2010). Project co-founder Barry Scheck
played himself in the episode, which was largely based on the actual
Innocence Project case of Cameron Todd Willingham. Cary Agos, a recurring character on The Good Wife, is written to have worked for the Innocence Project after law school (and is a family friend of Scheck's).
In season six of Suits, a US legal dramedy, law student and paralegal Rachel Zane takes on an Innocence Project for a man wrongfully accused of murder.
In season three of Riverdale, a dark reimagining of the Archie Comics universe, Veronica Lodge mentions starting a chapter of the organization to help free her boyfriend Archie Andrews from prison following being falsely convicted of murder.
Making a Murderer, a two-season (of 10 episodes each) documentary relating Steven Avery wrongful conviction. The episodes were released on Netflix between 2015 and 2018.
The Innocence Files (2020) is a series of nine documentary films based on the work of the Innocence Project, released on Netflix in April 2020.
Quantum Leap, in the episode "Ben Song for the Defense" the Innocence Project is mentioned after Ben, having leapt into a public defender, successfully defends a teenager wrongfully accused of killing a gang recruiter.
In biology, taxonomy (from Ancient Greekτάξις (taxis)'arrangement' and -νομία (-nomia)'method') is the scientific study of naming, defining (circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon), and these groups are given a taxonomic rank;
groups of a given rank can be aggregated to form a more inclusive group
of higher rank, thus creating a taxonomic hierarchy. The principal
ranks in modern use are domain, kingdom, phylum (division is sometimes used in botany in place of phylum), class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, having developed a ranked system known as Linnaean taxonomy for categorizing organisms.
With advances in the theory, data and analytical technology of
biological systematics, the Linnaean system has transformed into a
system of modern biological classification intended to reflect the evolutionary relationships among organisms, both living and extinct.
Definition
The exact definition of taxonomy varies from source to source, but
the core of the discipline remains: the conception, naming, and
classification of groups of organisms. As points of reference, recent definitions of taxonomy are presented below:
Theory and practice of grouping individuals into species,
arranging species into larger groups, and giving those groups names,
thus producing a classification.
A field of science (and a major component of systematics) that encompasses description, identification, nomenclature, and classification
The science of classification, in biology the arrangement of organisms into a classification
"The science of classification as applied to living organisms, including the study of means of formation of species, etc."
"The analysis of an organism's characteristics for the purpose of classification"
"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)
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, definition 6 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".
In 1970, Michener et al. defined "systematic biology" and "taxonomy" in relation to one another as follows:
Systematic biology (hereafter called simply systematics) is the field that
(a) provides scientific names for organisms,
(b) describes them,
(c) preserves collections of them,
(d) provides classifications for the organisms, keys for their identification, and data on their distributions,
(e) investigates their evolutionary histories, and
(f) considers their environmental adaptations.
This is a field with a long history that in recent years has
experienced a notable renaissance, principally with respect to
theoretical content. Part of the theoretical material has to do with
evolutionary areas (topics e and f above), the rest relates especially
to the problem of classification. Taxonomy is that part of Systematics
concerned with topics (a) to (d) above.
A whole set of terms including taxonomy, systematic biology, systematics, scientific classification, biological classification, and phylogenetics have at times had overlapping meanings – sometimes the same, sometimes slightly different, but always related and intersecting. The broadest meaning of "taxonomy" is used here. The term itself was introduced in 1813 by de Candolle, in his Théorie élémentaire de la botanique. John Lindley
provided an early definition of systematics in 1830, although he wrote
of "systematic botany" rather than using the term "systematics". 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. 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.
Monograph and taxonomic revision
A taxonomic revision or taxonomic review is a novel analysis of the variation patterns in a particular taxon.
This analysis may be executed on the basis of any combination of the
various available kinds of characters, such as morphological, anatomical, palynological, biochemical and genetic. A monograph
or complete revision is a revision that is comprehensive for a taxon
for the information given at a particular time, and for the entire
world. Other (partial) revisions may be restricted in the sense that
they may only use some of the available character sets or have a limited
spatial scope. A revision results in a conformation of or new insights
in the relationships between the subtaxa within the taxon under study,
which may lead to a change in the classification of these subtaxa, the
identification of new subtaxa, or the merger of previous subtaxa.
Taxonomic characters
Taxonomic characters are the taxonomic attributes that can be used to provide the evidence from which relationships (the phylogeny) between taxa are inferred. Kinds of taxonomic characters include:
The term "alpha taxonomy" is primarily used 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 19th 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.
... there is an increasing desire amongst taxonomists to consider their
problems from wider viewpoints, to investigate the possibilities of
closer co-operation with their cytological, ecological and genetics
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 upon 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.
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.
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. Thus, Ernst Mayr in 1968 defined "beta taxonomy" as the classification of ranks higher than species.
An
understanding of the biological meaning of variation and of the
evolutionary origin of groups of related species is even more important
for the second stage of taxonomic activity, the sorting of species into
groups of relatives ("taxa") and their arrangement in a hierarchy of
higher categories. This activity is what the term classification
denotes; it is also referred to as "beta taxonomy".
How species should be defined in a particular group of organisms
gives rise to practical and theoretical problems that are referred to as
the species problem. The scientific work of deciding how to define species has been called microtaxonomy. By extension, macrotaxonomy is the study of groups at the higher taxonomic ranks subgenus and above, or simply in clades that include more than one taxon considered a species, expressed in terms of phylogenetic nomenclature.
History
While some descriptions of taxonomic history attempt to date taxonomy
to ancient civilizations, a truly scientific attempt to classify
organisms did not occur until the 18th century, with the possible
exception of Aristotle, whose works hint at a taxonomy. Earlier works were primarily descriptive and focused on plants that were useful in agriculture or medicine.
There are a number of stages in this scientific thinking. Early
taxonomy was based on arbitrary criteria, the so-called "artificial
systems", including Linnaeus's system of sexual classification for plants (Linnaeus's 1735 classification of animals was entitled "Systema Naturae" ("the System of Nature"), implying that he, at least, believed that it was more than an "artificial system").
Later came systems based on a more complete consideration of the
characteristics of taxa, referred to as "natural systems", such as those
of de Jussieu (1789), de Candolle (1813) and Bentham and Hooker (1862–1863). These classifications described empirical patterns and were pre-evolutionary in thinking.
The publication of Charles Darwin's On the Origin of Species (1859) led to a new explanation for classifications, based on evolutionary relationships. This was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler (1883) and Engler (1886–1892).
The advent of cladistic methodology in the 1970s led to classifications based on the sole criterion of monophyly, supported by the presence of synapomorphies. Since then, the evidentiary basis has been expanded with data from molecular genetics that for the most part complements traditional morphology.
Pre-Linnaean
Early taxonomists
Naming and classifying human surroundings likely began with the onset
of language. Distinguishing poisonous plants from edible plants is
integral to the survival of human communities. Medicinal plant
illustrations show up in Egyptian wall paintings from c. 1500 BC, indicating that the uses of different species were understood and that a basic taxonomy was in place.
Organisms were first classified by Aristotle (Greece, 384–322 BC) during his stay on the island of Lesbos.He classified beings by their parts, or in modern terms attributes, such as having live birth, having four legs, laying eggs, having blood, or being warm-bodied. He divided all living things into two groups: plants and animals.
Some of his groups of animals, such as Anhaima (animals without blood, translated as invertebrates) and Enhaima (animals with blood, roughly the vertebrates), as well as groups like the sharks and cetaceans, are commonly used.
His student Theophrastus (Greece, 370–285 BC) carried on this tradition, mentioning some 500 plants and their uses in his Historia Plantarum. Several plant genera can be traced back to Theophrastus, such as Cornus, Crocus, and Narcissus.
Medieval
Taxonomy in the Middle Ages was largely based on the Aristotelian system, with additions concerning the philosophical and existential order of creatures. This included concepts such as the great chain of being in the Western scholastic tradition, again deriving ultimately from Aristotle.
The Aristotelian system did not classify plants or fungi, due to the lack of microscopes at the time, as his ideas were based on arranging the complete world in a single continuum, as per the scala naturae (the Natural Ladder). This, as well, was taken into consideration in the great chain of being.
Advances were made by scholars such as Procopius, Timotheus of Gaza, Demetrios Pepagomenos, and Thomas Aquinas.
Medieval thinkers used abstract philosophical and logical
categorizations more suited to abstract philosophy than to pragmatic
taxonomy. In the Muslim world, Al-Damiri (d. 1405) wrote an influential work called Life of Animals (Ḥayāt al-ḥayawān al-kubrā, c.1371) which treats in alphabetic order of 931 animals mentioned in the Quran, the traditions and the poetic and proverbial literature of the Arabs.
Renaissance and early modern
During the Renaissance and the Age of Enlightenment, categorizing organisms became more prevalent, and taxonomic works became ambitious enough to replace the ancient
texts. This is sometimes credited to the development of sophisticated
optical lenses, which allowed 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 the Italian physician Andrea Cesalpino (1519–1603), who has been called "the first taxonomist". His magnum opusDe Plantis came out in 1583, and described more than 1,500 plant species. Two large plant families that he first recognized are in use: the Asteraceae and Brassicaceae.
In the 17th century, John Ray (England, 1627–1705) wrote many important taxonomic works. Arguably his greatest accomplishment was Methodus Plantarum Nova (1682), in which he published details of 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 more than 9,000 species in 698 genera, which directly
influenced Linnaeus, as it was the text he used as a young student.
The Swedish botanist Carl Linnaeus (1707–1778) ushered in a new era of taxonomy. With his major works Systema Naturae 1st Edition in 1735, Species Plantarum in 1753, and Systema Naturae 10th Edition, 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. He not only introduced the standard of class,
order, genus, and species, but also made it possible to identify plants
and animals from his book, by using the smaller parts of the flower
(known as the Linnaean system).
Plant and animal taxonomists regard Linnaeus' work as the "starting point" for valid names (at 1753 and 1758 respectively). 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.
Evolution of the vertebrates at class level, width of spindles indicating number of families. Spindle diagrams are typical for evolutionary taxonomy.The same relationship, expressed as a cladogram typical for cladistics
A pattern of groups nested within groups was specified by Linnaeus'
classifications of plants and animals, and these patterns began to be
represented as dendrograms of the animal and plant kingdoms toward the end of the 18th century, well before Charles Darwin's On the Origin of Species was published. The pattern of the "Natural System" did not entail a generating
process, such as evolution, but may have implied it, inspiring early
transmutationist thinkers. Among early works exploring the idea of a transmutation of species were Zoonomia in 1796 by Erasmus Darwin (Charles Darwin's grandfather), and Jean-Baptiste Lamarck's Philosophie zoologique of 1809. The idea was popularized in the Anglophone world by the speculative but widely read Vestiges of the Natural History of Creation, published anonymously by Robert Chambers in 1844.
With Darwin's theory, a general acceptance quickly appeared that a classification should reflect the Darwinian principle of common descent. Tree of life
representations became popular in scientific works, with known fossil
groups incorporated. One of the first modern groups tied to fossil
ancestors was birds. Using the then newly discovered fossils of Archaeopteryx and Hesperornis, Thomas Henry Huxley pronounced that they had evolved from dinosaurs, a group formally named by Richard Owen in 1842. The resulting description, that of dinosaurs "giving rise to" or being "the ancestors of" birds, is the essential hallmark of evolutionary taxonomic thinking. As more and more fossil groups were found and recognized in the late 19th and early 20th centuries, palaeontologists worked to understand the history of animals through the ages by linking together known groups. With the modern evolutionary synthesis
of the early 1940s, an essentially modern understanding of the
evolution of the major groups was in place. As evolutionary taxonomy is
based on Linnaean taxonomic ranks, the two terms are largely
interchangeable in modern use.
The cladistic method has emerged since the 1960s. In 1958, Julian Huxley used the term clade. Later, in 1960, Cain and Harrison introduced the term cladistic. The salient feature is arranging taxa in a hierarchical evolutionary tree, with the desired objective of all named taxa being monophyletic. A taxon is called monophyletic if it includes all the descendants of an ancestral form. Groups that have descendant groups removed from them are termed paraphyletic, while groups representing more than one branch from the tree of life are called polyphyletic. Monophyletic groups are recognized and diagnosed on the basis of synapomorphies, shared derived character states.
Cladistic classifications are compatible with traditional Linnean taxonomy and the Codes of Zoological and Botanical nomenclature, to a certain extent. An alternative system of nomenclature, the International Code of Phylogenetic Nomenclature or PhyloCode has been proposed, which regulates the formal naming of clades. Linnaean ranks are optional and have no formal standing under the PhyloCode, which is intended to coexist with the current, rank-based codes. While popularity of phylogenetic nomenclature has grown steadily in the last few decades, it remains to be seen whether a majority of systematists will eventually adopt the PhyloCode
or continue using the current systems of nomenclature that have been
employed (and modified, but arguably not as much as some systematists
wish) for over 250 years.
The
basic scheme of modern classification. Many other levels can be used;
domain, the highest level within life, is both new and disputed.
Domains are a relatively new grouping. First proposed in 1977, Carl Woese's three-domain system was not generally accepted until later. One main characteristic of the three-domain method is the separation of Archaea and Bacteria, previously grouped into the single kingdom Bacteria (a kingdom also sometimes called Monera), with the Eukaryota for all organisms whose cells contain a nucleus. A small number of scientists include a sixth kingdom, Archaea, but do not accept the domain method.
Thomas Cavalier-Smith, who published extensively on the classification of protists, in 2002 proposed that the Neomura, the clade that groups together the Archaea and Eucarya, would have evolved from Bacteria, more precisely from Actinomycetota. His 2004 classification treated the archaeobacteria as part of a subkingdom of the kingdom Bacteria, i.e., he rejected the three-domain system entirely. Stefan Luketa in 2012 proposed a five "dominion" system, adding Prionobiota (acellular and without nucleic acid) and Virusobiota (acellular but with nucleic acid) to the traditional three domains.
Partial classifications exist for many individual groups of organisms
and are revised and replaced as new information becomes available;
however, comprehensive, published treatments of most or all life are
rarer; recent examples are that of Adl et al., 2012 and 2019, which covers eukaryotes only with an emphasis on protists, and Ruggiero et al., 2015, covering both eukaryotes and prokaryotes to the rank of Order, although both exclude fossil representatives. A separate compilation (Ruggiero, 2014) covers extant taxa to the rank of Family. Other, database-driven treatments include the Encyclopedia of Life, the Global Biodiversity Information Facility, the NCBI taxonomy database, the Interim Register of Marine and Nonmarine Genera, the Open Tree of Life, and the Catalogue of Life. The Paleobiology Database is a resource for fossils.
Application
Biological taxonomy is a sub-discipline of biology, and is generally practiced by biologists known as "taxonomists", although enthusiastic naturalists are also frequently involved in the publication of new taxa. Because taxonomy aims to describe and organize life, the work conducted by taxonomists is essential for the study of biodiversity and the resulting field of conservation biology.
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, species, and strain.
The description must be based on at least one name-bearing type specimen.
It should include statements about appropriate attributes either to
describe (define) the taxon or to differentiate it from other taxa (the
diagnosis, ICZN Code, Article 13.1.1, ICN, Article 38, which may or may not be based on morphology). Both codes deliberately separate defining the content of a taxon (its circumscription) from defining its name.
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.
An "authority" may be placed after a scientific name. The authority is the name of the scientist or scientists who first validly published the name. For example, in 1758, Linnaeus gave the Asian elephant the scientific name Elephas maximus, so the name is sometimes written as "Elephas maximus Linnaeus, 1758". The names of authors are often abbreviated: the abbreviation L., for Linnaeus, is commonly used. In botany, there is, in fact, a regulated list of standard abbreviations (see list of botanists by author abbreviation). The system for assigning authorities differs slightly between botany and zoology. However, it is standard that if the genus of a species has been changed
since the original description, the original authority's name is placed
in parentheses.
A comparison of phylogenetic and phenetic (character-based) concepts
In phenetics, also known as taximetrics, or numerical taxonomy,
organisms are classified based on overall similarity, regardless of
their phylogeny or evolutionary relationships. It results in a measure of hypergeometric "distance" between taxa.
Phenetic methods have become relatively rare in modern times, largely
superseded by cladistic analyses, as phenetic methods do not distinguish shared ancestral (or plesiomorphic) traits from shared derived (or apomorphic) traits. However, certain phenetic methods, such as neighbor joining, have persisted, as rapid estimators of relationships when more advanced methods (such as Bayesian inference) are too computationally expensive.
Modern taxonomy uses database technologies to search and catalogue 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 1.64 million species for all kingdoms as of April 2016, claiming coverage of more than three-quarters of the estimated species known to modern science.
