View source for Phylogenetic comparative methods

{{short description|Use of information on the historical relationships of lineages to test evolutionary hypotheses}}
{{Use dmy dates|date=February 2016}}
'''Phylogenetic comparative methods''' ('''PCMs''') use information on the historical relationships of lineages ([[phylogenies]]) to test evolutionary hypotheses. The comparative method has a long history in evolutionary biology; indeed, [[Charles Darwin]] used differences and similarities between species as a major source of evidence in ''[[The Origin of Species]]''. However, the fact that closely related lineages share many traits and trait combinations as a result of the process of descent with modification means that lineages are not independent. This realization inspired the development of explicitly phylogenetic comparative methods.<ref name=f85 /> Initially, these methods were primarily developed to control for phylogenetic history when testing for [[adaptation]]<ref name=harvey1991/>; however, in recent years the use of the term has broadened to include any use of phylogenies in statistical tests.<ref name=omeara2012 /> Although most studies that employ PCMs focus on extant organisms, many methods can also be applied to extinct taxa and can incorporate information from the [[fossil record]].<ref name=pennell2012 />

PCMs can generally be divided into two types of approaches: those that infer the evolutionary history of some character ([[phenotypic]] or [[genetics|genetic]]) across a phylogeny and those that infer the process of evolutionary branching itself ([[diversification rates]]), though there are some approaches that do both simultaneously.<ref name=maddison2007 /> Typically the tree that is used in conjunction with PCMs has been estimated independently (see [[computational phylogenetics]]) such that both the relationships between lineages and the length of branches separating them is assumed to be known.

== Applications ==

Phylogenetic comparative approaches can complement other ways of studying adaptation, such as studying natural populations, experimental studies, and mathematical models.<ref name=weber2012 /> Making interspecific comparisons allow researchers to assess the generality of evolutionary phenomena by considering independent evolutionary events. Such an approach is particularly useful when there is little or no variation within species. And because they can be used to explicitly model evolutionary processes occurring over very long time periods, they can provide insight into macroevolutionary questions, once the exclusive domain of [[paleontology]].<ref name=pennell2012 />

[[File:Home Range 49 Mammals 1.jpg|thumb|left|[[Home range]] areas of 49 species of [[mammals]] in relation to their [[body size]].  Larger-bodied species tend to have larger home ranges, but at any given body size members of the order [[Carnivora]] ([[carnivores]] and [[omnivores]]) tend to have larger home ranges than [[ungulates]] (all of which are [[herbivores]]).  Whether this difference is considered statistically significant depends on what type of analysis is applied<ref name=garland1993 />]]

[[File:Primate Testes Allometry Sexual Selection.jpg|thumb|right|[[Testes]] mass of various species of [[Primates]] in relation to their [[body size]] and mating system.  Larger-bodied species tend to have larger testes, but at any given body size species in which females tend to mate with multiple males have males with larger testes.]]

Phylogenetic comparative methods are commonly applied to such questions as:

* What is the [[slope]] of an [[allometric]] scaling relationship?
→ ''Example:  how does [[Brain-to-body mass ratio|brain mass vary in relation to body mass]]?''
* Do different [[clades]] of organisms differ with respect to some [[phenotypic]] trait?
→ ''Example:  do [[Canidae|canids]] have larger hearts than [[Felidae|felids]]?''
* Do groups of species that share a [[behavioral]] or ecological feature (e.g., [[social system]], [[diet (nutrition)|diet]]) differ in average phenotype?
→ ''Example:  do carnivores have larger [[home range]]s than herbivores?''
* What was the [[ancestral]] state of a [[Phenotypic trait|trait]]?
→ ''Example:  where did [[endothermy]] evolve in the lineage that led to mammals?''

→ ''Example:  where, when, and why did [[placenta]]s and [[viviparity]] evolve?''
* Does a trait exhibit significant phylogenetic signal in a particular group of organisms?  Do certain types of traits tend to "follow phylogeny" more than others?
→ ''Example:  are behavioral traits [[Phenotypic plasticity|more labile]] during evolution?''
* Do species differences in [[Life history theory|life history traits]] trade-off, as in the so-called fast-slow continuum?
→ ''Example:  why do small-bodied species have shorter [[life expectancy|life spans]] than their larger relatives?''

== Phylogenetically independent contrasts ==

[[File:Phylogenetically Independent Contrasts 1.jpg|thumb|left|The standardized contrasts are used in conventional statistical procedures, with the constraint that all [[Regression analysis|regressions]], [[correlations]], [[analysis of covariance]], etc., must pass through the origin.]]

[[Joseph Felsenstein|Felsenstein]]<ref name=f85 /> proposed the first general statistical method in 1985 for incorporating phylogenetic information, i.e., the first that could use any arbitrary [[topology]] (branching order) and a specified set of branch lengths.  The method is now recognized as an [[algorithm]] that implements a special case of what are termed phylogenetic [[generalized least-squares]] models.<ref name=grafen1989 /> The [[logic]] of the method is to use phylogenetic information (and an assumed [[Brownian motion]] like model of trait evolution) to transform the original tip data (mean values for a set of species) into values that are [[statistically independent]] and [[identically distributed]].

The algorithm involves computing values at [[internal node]]s as an intermediate step, but they are generally not used for [[inferences]] by themselves.  An exception occurs for the basal (root) node, which can be interpreted as an estimate of the ancestral value for the entire tree (assuming that no directional [[evolutionary trends]] [e.g., [[Cope's rule]]] have occurred) or as a phylogenetically weighted estimate of the mean for the entire set of tip species (terminal taxa).  The value at the root is equivalent to that obtained from the "squared-change parsimony" algorithm and is also the maximum likelihood estimate under Brownian motion.  The independent contrasts algebra can also be used to compute a [[standard error]] or [[confidence interval]].

== Phylogenetic generalized least squares (PGLS) ==

Probably the most commonly used PCM is phylogenetic generalized least squares (PGLS).<ref name=grafen1989 /><ref name=martins1997 /> This approach is used to test whether there is a relationship between two (or more) variables while accounting for the fact that lineage are not independent. The method is a special case of [[generalized least squares]] (GLS) and as such the PGLS estimator is also [[Bias of an estimator|unbiased]], [[consistent estimator|consistent]], [[efficiency (statistics)|efficient]], and [[asymptotic distribution|asymptotically normal]].<ref name=rohlf2001 /> In many statistical situations where GLS (or, [[ordinary least squares]] [OLS]) is used residual errors ''ε'' are assumed to be independent and identically distributed random variables that are assumed to be normal
: <math>
    \varepsilon \mid X\sim \mathcal{N}(0, \sigma^2I_n).
  </math>
whereas in PGLS the errors are assumed to be distributed as
: <math>
    \varepsilon \mid X\sim \mathcal{N}(0, \mathbf{V}).
  </math>
where ''V'' is a matrix of expected variance and covariance of the residuals given an evolutionary model and a phylogenetic tree. Therefore, it is the structure of residuals and not the variables themselves that show [[phylogenetic signal]]. This has long been a source of confusion in the scientific literature.<ref name=revell2010 /> A number of models have been proposed for the structure of ''V'' such as [[Brownian motion]]<ref name=grafen1989 /> [[Ornstein–Uhlenbeck process|Ornstein-Uhlenbeck]],<ref name=butler2000 /> and Pagel's λ model.<ref name=freckleton2002 /> (When a Brownian motion model is used, PGLS is identical to the independent contrasts estimator.<ref name=blomberg2012 />). In PGLS, the parameters of the evolutionary model are typically co-estimated with the regression parameters.

PGLS can only be applied to questions where the [[dependent variable]] is continuously distributed; however, the phylogenetic tree can also be incorporated into the residual distribution of [[generalized linear models]], making it possible to generalize the approach to a broader set of distributions for the response.<ref>{{cite journal|last1=Lynch|first1=Michael|title=Methods for the Analysis of Comparative Data in Evolutionary Biology|journal=Evolution|date=August 1991|volume=45|issue=5|pages=1065|doi=10.2307/2409716}}</ref><ref>{{cite journal|last1=Housworth|first1=Elizabeth A.|last2=Martins|first2=Emília P.|last3=Lynch|first3=Michael|title=The Phylogenetic Mixed Model|journal=The American Naturalist|date=January 2004|volume=163|issue=1|pages=84–96|doi=10.1086/380570}}</ref><ref>{{cite journal|last1=Hadfield|first1=J. D.|last2=Nakagawa|first2=S.|title=General quantitative genetic methods for comparative biology: phylogenies, taxonomies and multi-trait models for continuous and categorical characters|journal=Journal of Evolutionary Biology|date=March 2010|volume=23|issue=3|pages=494–508|doi=10.1111/j.1420-9101.2009.01915.x|pmid=20070460}}</ref>

== Phylogenetically informed Monte Carlo computer simulations ==

[[File:Phylogenetic Computer Simulations 1.jpg|thumb|right|Data for a continuous-valued trait can be simulated in such a way that taxa at the tips of a hypothetical phylogenetic tree will exhibit phylogenetic signal, i.e., closely related species will tend to resemble each other.]]

Martins and Garland<ref name=martins1991 /> proposed in 1991 that one way to account for phylogenetic relations when conducting statistical analyses was to use computer simulations to create many data sets that are consistent with the null hypothesis under test (e.g., no correlation between two traits, no difference between two ecologically defined groups of species) but that mimic evolution along the relevant phylogenetic tree.  If such data sets (typically 1,000 or more) are analyzed with the same statistical procedure that is used to analyze a real data set, then results for the simulated data sets can be used to create phylogenetically correct (or "PC"<ref name=garland1993 />) null distributions of the test statistic (e.g., a correlation coefficient, t, F).  Such simulation approaches can also be combined with such methods as phylogenetically independent contrasts or PGLS (see above).

[[File:Phylogenetic Pseudoreplication.jpg|thumb|left]]

== See also ==
{{div col|colwidth=22em}}
* [[Allometry]]
* [[Behavioral ecology]]
* [[Biodiversity]]
* [[Bioinformatics]]
* [[Cladistics]]
* [[Comparative anatomy]]
* [[Comparative method]] in linguistics
* [[Comparative physiology]]
* [[Computational phylogenetics]]
* [[Disk-covering method]]
* [[Ecophysiology]]
* [[Evolutionary neurobiology]]
* [[Evolutionary physiology]]
* [[Generalized least squares]] (GLS)
* [[Generalized linear model]]
* [[Joe Felsenstein]]
* [[Mark Pagel]]
* [[Maximum likelihood]]
* [[Maximum parsimony]]
* [[Paul H. Harvey]]
* [[Phylogenetics]]
* [[Roderic D.M. Page]]
* [[Sexual selection]]
* Statistics
* [[Systematics]]
* [[Theodore Garland, Jr.]]
{{div col end}}

== References ==
{{Reflist|30em|refs=
<ref name=f85>{{cite journal|last1=Felsenstein|first1=Joseph|title=Phylogenies and the Comparative Method|journal=The American Naturalist|date=January 1985|volume=125|issue=1|pages=1|doi=10.1086/284325}}</ref>
<ref name=harvey1991>{{cite book|last1=Harvey|first1=Paul H.|last2=Pagel|first2=Mark D.|title=The Comparative Method in Evolutionary Biology|date=1991|publisher=Oxford University Press|location=Oxford|isbn=9780198546405|pages=248}}</ref>
<ref name=omeara2012>{{cite journal|last1=O'Meara|first1=Brian C.|title=Evolutionary Inferences from Phylogenies: A Review of Methods|journal=Annual Review of Ecology, Evolution, and Systematics|date=December 2012|volume=43|issue=1|pages=267–285|doi=10.1146/annurev-ecolsys-110411-160331}}</ref>
<ref name=pennell2012>{{cite journal|last1=Pennell|first1=Matthew W.|last2=Harmon|first2=Luke J.|title=An integrative view of phylogenetic comparative methods: connections to population genetics, community ecology, and paleobiology|journal=Annals of the New York Academy of Sciences|date=June 2013|volume=1289|issue=1|pages=90–105|doi=10.1111/nyas.12157|pmid=23773094}}</ref>
<ref name=maddison2007>{{cite journal|last1=Maddison|first1=Wayne|last2=Midford|first2=Peter|last3=Otto|first3=Sarah|title=Estimating a Binary Character's Effect on Speciation and Extinction|journal=Systematic Biology|date=October 2007|volume=56|issue=5|pages=701–710|doi=10.1080/10635150701607033|pmid=17849325}}</ref> 
<ref name=weber2012>{{cite journal|last1=Weber|first1=Marjorie G.|last2=Agrawal|first2=Anurag A.|title=Phylogeny, ecology, and the coupling of comparative and experimental approaches|journal=Trends in Ecology & Evolution|date=July 2012|volume=27|issue=7|pages=394–403|doi=10.1016/j.tree.2012.04.010}}</ref>
<ref name=garland1993>{{cite journal|last1=Garland|first1=T.|last2=Dickerman|first2=A. W.|last3=Janis|first3=C. M.|last4=Jones|first4=J. A.|title=Phylogenetic Analysis of Covariance by Computer Simulation|journal=Systematic Biology|date=1 September 1993|volume=42|issue=3|pages=265–292|doi=10.1093/sysbio/42.3.265}}</ref>
<ref name=grafen1989>{{cite journal|last1=Grafen|first1=A.|title=The Phylogenetic Regression|journal=Philosophical Transactions of the Royal Society B: Biological Sciences|date=21 December 1989|volume=326|issue=1233|pages=119–157|doi=10.1098/rstb.1989.0106}}</ref>
<ref name=martins1997>{{cite journal|last1=Martins|first1=Emilia P.|last2=Hansen|first2=Thomas F.|title=Phylogenies and the Comparative Method: A General Approach to Incorporating Phylogenetic Information into the Analysis of Interspecific Data|journal=The American Naturalist|date=April 1997|volume=149|issue=4|pages=646–667|doi=10.1086/286013}}</ref>
<ref name=rohlf2001>{{cite journal|last1=Rohlf|first1=F. James|title=Comparative methods for the analysis of continuous variables: geometric interpretations|journal=Evolution|date=November 2001|volume=55|issue=11|pages=2143–2160|doi=10.1111/j.0014-3820.2001.tb00731.x}}</ref>
<ref name=revell2010>{{cite journal|last1=Revell|first1=Liam J.|title=Phylogenetic signal and linear regression on species data|journal=Methods in Ecology and Evolution|date=December 2010|volume=1|issue=4|pages=319–329|doi=10.1111/j.2041-210x.2010.00044.x}}</ref>
<ref name=butler2000>{{cite journal|last1=Butler|first1=Marguerite A.|last2=Schoener|first2=Thomas W.|last3=Losos|first3=Jonathan B.|title=The relationship between sexual size dimorphism and habitat use in Greater Antillean lizards|journal=Evolution|date=February 2000|volume=54|issue=1|pages=259–272|doi=10.1111/j.0014-3820.2000.tb00026.x|pmid=10937202}}</ref>
<ref name=freckleton2002>{{cite journal|last1=Freckleton|first1=R. P.|last2=Harvey|first2=P. H.|last3=Pagel|first3=M.|title=Phylogenetic Analysis and Comparative Data: A Test and Review of Evidence|journal=The American Naturalist|date=December 2002|volume=160|issue=6|pages=712–726|doi=10.1086/343873|pmid=18707460}}</ref>
<ref name=blomberg2012>{{cite journal|last1=Blomberg|first1=S. P.|last2=Lefevre|first2=J. G.|last3=Wells|first3=J. A.|last4=Waterhouse|first4=M.|title=Independent Contrasts and PGLS Regression Estimators Are Equivalent|journal=Systematic Biology|date=3 January 2012|volume=61|issue=3|pages=382–391|doi=10.1093/sysbio/syr118|pmid=22215720}}</ref>
<ref name=martins1991>{{cite journal|last1=Martins|first1=Emilia P.|last2=Garland|first2=Theodore|title=Phylogenetic Analyses of the Correlated Evolution of Continuous Characters: A Simulation Study|journal=Evolution|date=May 1991|volume=45|issue=3|pages=534|doi=10.2307/2409910}}</ref>
}}

==Further reading==
{{refbegin}}
* Ackerly, D. D. 1999. Comparative plant ecology and the role of phylogenetic information. Pages 391–413 in M. C. Press, J. D. Scholes, and M. G. Braker, eds. Physiological plant ecology. The 39th symposium of the British Ecological Society held at the University of York 7–9 September 1998. Blackwell Science, Oxford, U.K.
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* {{cite journal | last1 = Blomberg | first1 = S. P. | authorlink2 = Theodore Garland, Jr. | last2 = Jr | first2 =  | last3 = Garland | first3 = T. | last4 = Ives | first4 = A. R. | year = 2003 | title = Testing for phylogenetic signal in comparative data: behavioral traits are more labile | url = http://biology.ucr.edu/people/faculty/Garland/BlomEA03.pdf | format = PDF | journal = Evolution | volume = 57 | issue = | pages = 717–745 | doi=10.1554/0014-3820(2003)057[0717:tfpsic]2.0.co;2}}
* Brooks, D. R., and D. A. McLennan. 1991. Phylogeny, ecology, and behavior: a research program in comparative biology. Univ. Chicago Press, Chicago. 434 pp.
* {{cite journal | last1 = Cheverud | first1 = J. M. | last2 = Dow | first2 = M. M. | last3 = Leutenegger | first3 = W. | year = 1985 | title = The quantitative assessment of phylogenetic constraints in comparative analyses: sexual dimorphism in body weight among primates | url = | journal = Evolution | volume = 39 | issue = | pages = 1335–1351 | doi=10.2307/2408790}}
* Eggleton, P., and R. I. Vane-Wright, eds. 1994. Phylogenetics and ecology. Linnean Society Symposium Series Number 17. Academic Press, London.
* [[Joe Felsenstein|Felsenstein, J.]] 2004. Inferring phylogenies. Sinauer Associates, Sunderland, Mass. xx + 664 pp.
* {{cite journal | last1 = Freckleton | first1 = R. P. | last2 = Harvey | first2 = P. H. | last3 = Pagel | first3 = M. | year = 2002 | title = Phylogenetic analysis and comparative data: a test and review of evidence | url = | journal = American Naturalist | volume = 160 | issue = | pages = 712–726 | doi=10.1086/343873 | pmid=18707460}}
* {{cite journal | authorlink= Theodore Garland, Jr. | last1 = Garland Jr | first1 = T | last2 = Ives | first2 = A. R. | year = 2000 | title = Using the past to predict the present: Confidence intervals for regression equations in phylogenetic comparative methods | url = http://biology.ucr.edu/people/faculty/Garland/GarlIv00.pdf | format = PDF | journal = American Naturalist | volume = 155 | issue = | pages = 346–364 | doi = 10.1086/303327 }}
* {{cite journal | last1 = Garland Jr | first1 = T. | last2 = Bennett | first2 = A. F. | last3 = Rezende | first3 = E. L. | year = 2005 | title = Phylogenetic approaches in comparative physiology | url = http://biology.ucr.edu/people/faculty/Garland/GarlandEA2005_JEBCM.pdf | format = PDF | journal = Journal of Experimental Biology | volume = 208 | issue = | pages = 3015–3035 | doi=10.1242/jeb.01745 | pmid=16081601}}
* {{cite journal | last1 = Garland Jr | first1 = T. | last2 = Harvey | first2 = P. H. | last3 = Ives | first3 = A. R. | year = 1992 | title = Procedures for the analysis of comparative data using phylogenetically independent contrasts | url = http://biology.ucr.edu/people/faculty/Garland/GarlEA92.pdf | format = PDF | journal = Systematic Biology | volume = 41 | issue = | pages = 18–32 | doi=10.2307/2992503}}
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* {{cite journal | last1 = Hadfield | first1 = J. D | last2 = Nakagawa | first2 = S. | year = 2010 | title = General quantitative genetic methods for comparative biology: phylogenies, taxonomies and multi-trait models for continuous and categorical characters | url = | journal = Journal of Evolutionary Biology | volume = 23 | issue = | pages = 494–508 | doi=10.1111/j.1420-9101.2009.01915.x | pmid=20070460}}
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* {{cite journal | last1 = Maddison | first1 = D. R. | year = 1994 | title = Phylogenetic methods for inferring the evolutionary history and process of change in discretely valued characters | url = | journal = Annual Review of Entomology | volume = 39 | issue = | pages = 267–292 | doi=10.1146/annurev.ento.39.1.267}}
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* {{cite journal | last1 = Schluter | first1 = D. | last2 = Price | first2 = T. | last3 = Mooers | first3 = A. O. | last4 = Ludwig | first4 = D. | year = 1997 | title = Likelihood of ancestor states in adaptive radiation | url = | journal = Evolution | volume = 51 | issue = | pages = 1699–1711 | doi=10.2307/2410994}}
* {{cite journal | last1 = Smith | first1 = R. J. | last2 = Cheverud | first2 = J. M. | year = 2002 | title = Scaling of sexual size dimorphism in body mass: a phylogenetic analysis of Rensch's rule in primates | doi = 10.1023/A:1019654100876 | journal = International Journal of Primatology | volume = 23 | issue = | pages = 1095–1135 }}
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* {{cite journal | last1 = Vanhooydonck | first1 = B. | last2 = Van Damme | first2 = R. | year = 1999 | title = Evolutionary relationships between body shape and habitat use in lacertid lizards | url = | journal = Evolutionary Ecology Research | volume = 1 | issue = | pages = 785–805 }}
{{refend}}

== External links ==
* [http://idea.ucr.edu/documents/flash/adaptation_and_the_comparative_method_1/story.htm  Adaptation and the comparative method online lecture, with worked example of phylogenetically independent contrasts and mastery quiz]
* [http://evolution.genetics.washington.edu/phylip/software.html List of phylogeny programs]
* [http://phylodiversity.net/phylocom/  Phylocomm]
* [http://blog.phytools.org/  Phylogenetic Tools for Comparative Biology]
* [http://www.bu.edu/phylogeny/ Phylogeny of Sleep website]
* [http://tolweb.org/tree/ Tree of Life]

===Journals===
* [http://www.journals.uchicago.edu/AN/ American Naturalist]
* [http://beheco.oxfordjournals.org/ Behavioral Ecology]
* [http://esapubs.org/esapubs/journals/ecology.htm Ecology]
* [http://www.blackwellpublishing.com/journal.asp?ref=0014-3820&site=1 Evolution]
* [http://www.evolutionary-ecology.com/ Evolutionary Ecology Research]
* [http://www.blackwellpublishing.com/journal.asp?ref=0269-8463&site=1 Functional Ecology]
* [http://www.blackwellpublishing.com/journal.asp?ref=1010-061X&site=1 Journal of Evolutionary Biology]
* [http://www.pubs.royalsoc.ac.uk/index.cfm?page=1085 Philosophical Transactions of the Royal Society of London B]
* [http://www.journals.uchicago.edu/PBZ/home.html Physiological and Biochemical Zoology]
* [http://systbiol.org/ Systematic Biology]

=== Software packages (incomplete list) ===
* [http://ape-package.ird.fr/  Analyses of Phylogenetics and Evolution]
* [http://www.evolution.rdg.ac.uk/BayesTraits.html BayesTraits]
* [http://www.bio.ic.ac.uk/evolve/software/caic/  Comparative Analysis by Independent Contrasts]
* [http://www.indiana.edu/~martinsl/compare/  COMPARE]
* [http://evolution.genetics.washington.edu/phylip/software.html  Felsenstein's List]
* [http://mesquiteproject.org/mesquite/download/download.html  Mesquite] [http://mesquiteproject.org/pdap_mesquite/index.html  PDAP:PDTree for Mesquite]
* [https://cran.r-project.org/web/packages/mvMORPH/ mvMorph]
* [https://kingaa.github.io/ouch/  ouch: Ornstein-Uhlenbeck for Comparative Hypotheses]
* [http://biology.ucr.edu/people/faculty/Garland/PDAP.html  PDAP: Phenotypic Diversity Analysis Programs]
* [http://www.phylodiversity.net/phylocom/  Phylocom]
* [http://users.ox.ac.uk/~grafen/phylo/index.html  Phylogenetic Regression]
* [http://biology.ucr.edu/people/faculty/Garland/PHYSIG.html  PHYSIG]

===Laboratories===
{{div col|colwidth=15em}}
* [http://ib.berkeley.edu/labs/ackerly/  Ackerly]
* [http://www.personal.uni-jena.de/~b6biol2/  Bininda-Emonds]
* [http://www.evolutionarystatistics.org/  Blomberg]
* [http://www2.hawaii.edu/~mbutler/  Butler]
* [http://www.biology.washington.edu/index.html?navID=42&parecID=106  Felsenstein]
* [http://www.shef.ac.uk/aps/staff/acadstaff/freckleton.html  Freckleton]
* [http://biology.ucr.edu/people/faculty/Garland.html  Garland]
* [http://www.virginia.edu/biology/Fac/Gittleman.html  Gittleman]
* [http://users.ox.ac.uk/~grafen/  Grafen]
* [http://www.cees.no/?option=com_staff&person=thomasha  Hansen]
* [http://www.webpages.uidaho.edu/~lukeh/  Harmon]
* [http://evolve.zoo.ox.ac.uk/people.html?id=harveyp  Harvey]
* [http://mypage.iu.edu/~ehouswor/  Housworth]
* [http://www.bio.umass.edu/biology/irschick/irschickcv.html  Irschick]
* [https://ives.labs.wisc.edu  Ives]
* [http://www.oeb.harvard.edu/faculty/losos/  Losos]
* [http://www.bio.indiana.edu/facultyresearch/faculty/Martins.html  Martins]
* [https://www.sfu.ca/~amooers/index.html  Mooers]
* [http://www2.ku.edu/~eeb/faculty/mort.shtml Mort]
* [http://www.eva.mpg.de/primat/staff/charles_nunn/  Nunn]
* [http://www.lifesci.ucsb.edu/eemb/labs/oakley/  Oakley]
* [http://taxonomy.zoology.gla.ac.uk/rod/rod.html  Page]
* [http://www.evolution.rdg.ac.uk/index.html  Pagel]
* [http://ape-package.ird.fr/ep/  Paradis]
* [http://www.bio.ic.ac.uk/research/apurvis/ajpurvis.htm  Purvis]
* [http://tree.bio.ed.ac.uk/  Rambaut]
* [http://life.bio.sunysb.edu/ee/rohlf/  Rohlf]
* [http://ginger.ucdavis.edu/  Sanderson]
{{div col end}}

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