Mark Pagel talks with
ScienceWatch.com and answers a few questions about
this month's Emerging Research Front Paper in the field of
Article: Phylogenetic analysis and comparative data: A
test and review of evidence
Authors: Freckleton, RP;Harvey, PH;Pagel,
Journal: AMER NATURALIST, 160 (6): 712-726 DEC 2002
Address: Univ Oxford, Dept Zool, S Parks Rd, Oxford OX1 3PS,
Univ Oxford, Dept Zool, Oxford OX1 3PS, England.
Univ Reading, Sch Anim & Microbial Sci, Reading RG6 6AJ,
Why do you think your paper is highly
The paper reports a statistic that everyone who uses phylogenies for
comparative studies is interested to estimate. Comparative studies make
comparisons between species on the value of some trait or traits.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
The paper describes and evaluates a statistical method that I introduced in
an earlier paper (Pagel, Nature, 1999). Together with Robert P.
Freckleton, a Royal Society University Research Fellow and Professor of
Population Biology, University of Sheffield, and Paul H. Harvey of the
Department of Zoology, University of Oxford, we performed computer
simulations of the statistic's performance. These simulations are useful
for people who want to use the statistic because they show that it is
effective in a wide range of circumstances.
Would you summarize the significance of your paper in
The statistic, known as "lambda," calculates the strength of the
association between the value of some trait that is measured on a species,
such as its body size, and its position in the phylogenetic tree. We
normally expect species that are closely related—near to each other
on the tree—to be similar on their traits. Lambda measures the
strength of that association, which is important to know when doing
How did you become involved in this research and were
any particular problems encountered along the way?
I have been working in this area for about 20 years.
Where do you see your research leading in the
We are planning new methods for studying trait evolution on phylogenies.
Mark Pagel, Ph.D.
Professor of Evolutionary Biology
School of Biological Sciences
University of Reading
BBC audio: Professor Mark Pagel discusses his
research into the oldest words in the English language.
KEYWORDS: COMPUTER-SIMULATION TEST; CORRELATED EVOLUTION;
INDEPENDENT CONTRASTS; HABITAT USE; BODY-SIZE; CONTINUOUS CHARACTERS;
GEOGRAPHICAL RANGE; ANOLIS LIZARDS; CONSTRAINTS; ADAPTATION.