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30 de septiembre de 2009

Taxonomy comes of age: Book review in Nature

Taxonomy comes of age : Article : Nature

BOOK REVIEWED


Naming Nature: The Clash Between Instinct and Science
by Carol Kaesuk Yoon.
W. W. Norton
: 2009.
352 pp.

Faced with the bewildering diversity of nature, humans have long attempted to classify it. In her personal and readable perspective on taxonomy, Carol Yoon argues that the basic instinct to recognize natural groups has gradually been replaced by an increased rationality.

Yoon explores the formative environment, motives and personality of the field and scientists within it, from its origins to maturity. She argues that taxonomy generates new views of the world that are counterintuitive, for example that fungi are more like animals than plants; reductionist, depending on molecular data and statistical techniques; and bewildering, such as the prolific yet invisible domains of bacteria and archaea. She is concerned that the professionalization of biology has distanced humanity from nature. But her incursions into anthropology, neuroscience and psychology to explain our empathy with nature are disappointingly superficial.

The first major step in taxonomy was taken by Carl Linneaus some 250 years ago. In a magnificent work, Systema Naturae, he ordered the known natural world. Although the places of some organisms in his scheme have changed, his binomial system for naming organisms has stood the test of time.

A century later, in 1859, came Darwin's theory of evolution, with its seismic impact on science and society. Surprisingly, its effect on taxonomy was minimal. Taxonomists continued for another century to explore the world and discover new species as before, now drawing tree diagrams to represent the relationships between organisms and their evolution. Some of these evolutionary trees were insightful, others fanciful. Unfortunately none was testable, repeatable or objective. So taxonomy got a bad name.

Yoon rightly recognizes the role of the 1960s movement of quantitative experimentalists in being the most significant first step in transforming the field into a full science. These numerical taxonomists started a serious debate on how to articulate earlier opinions and experience, and distil them into testable conclusions. As a result, data and transparent methodology came to challenge 'expert' opinion. However, these researchers treated all data equally, without considering their relative evolutionary or biological significance.

A more rational and evolution-based approach was needed. For some this was found in DNA sequences. But this approach attracted a similar criticism, namely that a complex organism couldn't be reduced to a string of nucleotides.

Over the following period of great change in biology and computational technology, taxonomists struggled to find their way. In the 1970s, the phylogenetics movement arose with a simple message: to seek close relatives with similarities that are shared uniquely by their descendants and no other groups. With this powerful new methodological tool came fervent disciples, called 'cladists', who wanted to purge the field of non-adherents. Taxonomy again turned in on itself, ignoring the huge strides being made in areas such as developmental genetics, population genetics and population biology that could have crucially informed their interpretations of nature. Describing these ideological waves, Yoon's book comes alive with her tales of meeting influential figures, including the God-like Ernst Mayr.

Yoon leaves us with taxonomy having passed though its rebellious adolescence into maturity. But what of its future? Taxonomy has never had so many tools at its disposal and so many connections to the rest of biology. The tragedy is that there are too few taxonomists who can utilize these advances and tackle the challenging questions of our time.


Book review by
Richard Lane. Director of science at the Natural History Museum, London SW7 5BD, UK, and author of the recent report Taxonomy in Europe in the 21st Century.

23 de septiembre de 2009

La dimensión filogenética de la diversidad biológica

Curso de Posgrado en la Universidad Nacional del Sur, Bahía Blanca, Buenos Aires.

"La dimensión filogenética de la diversidad biológica"

a cargo del Dr. Fernando Pérez-Miles (Sección Entomología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay)

Coordinador responsable: Dra. Adriana Ferrero
  • Lugar: Sala de Conferencias, Depto. De Biología, Bioquímica y Farmacia
  • Fecha de Inicio: lunes 19 de octubre, 17 horas.
  • Modalidad: Teórico – Práctico
Contacto: Lic. Nelson Ferretti, Laboratorio de Zoologia de Invertebrados II, Tel: 4595101 Int. 2425. Email

Temario Básico
Programa Teórico:

1.- Diversidad biológica y Sistemática. Bases criterios y formas de clasificación. Características de las clasificaciones científicas, jerarquía y claves. Sistemática, Taxonomía, Clasificación y Nomenclatura. El concepto de especie en sistemática.

2.- Referencias históricas de la sistemática, escuelas. Origen de la Sistemática Cladista. Filogenia y Parentesco. Principios Cladistas: parsimonia, máxima verosimilitud y distancia.

3.- Caracteres sistemáticos y variación. Tipos de caracteres. Variables cualitativas y cuantitativas. Variables discretas y contínuas. Transformación y estados de los caracteres. Homología y homoplasia. Codificación de caracteres. Ordenamiento y polarización. Criterios de optimalidad y optimización de caracteres.

4.- Construcción de cladogramas. Búsquedas: métodos exactos, métodos heurísticos. Permutación de ramas: podado y reinserción de sub-árboles (SPR), corte y reconección (TBR). Polaridad y enraizamiento. 9.- Pesado de caracteres y medidas de ajuste. Longitud del cladograma. Indices de consistencia, de retención y ajuste. Pesado a priori y a posteriori. Pesajes sucesivos y pesajes implicados.

5.- Soporte y medidas de confiabilidad de cladogramas y grupos. Decisividad, distribución de longitudes de árboles, “Bremer support”. Métodos probabilísticos: Bootstrap, Jacknife. Consensos: estricto, de mayoría, de Nelson, de Adams. Análisis separados versus evidencia total. Comentarios sobre nuevos métodos de búsqueda para matrices muy grandes o “sucias”.


Programa Práctico:
1.- Polarización y codificación de caracteres, matrices básicas de datos, manejo básico del programa NEXUS

2.- Análisis filogenético, búsquedas de árboles por parsimonia, manejo básico del programa TNT.

3.- Pensando en árboles, ejercicios (domiciliarios) de interpretación de árboles.


Bibliografía:

Libros

Goloboff, P.A. 1998. Principios basicos de cladística. Sociedad Argentina de Botánica, Buenos Aires, 81 pp.

Kitching, I.J., P.L. Forey, C.J. Humphries & D. M. Williams. 1998. Cladistics. The theory and practice of parsimony analysis. 2nd. Ed. Oxford Univ. Press, Oxford, 228 pp.

Lanteri, A.A. & M.M. Cigliano. Sistemática biológica fundamentos teóricos y ejercitaciones. Edlup, La Plata, 241 pp.

Diniz, J.A.F. 2000. Métodos filogenéticos comparativos. Holos, Riberao Preto, 162 pp.



Trabajos científicos

Bremer, K.1994. Branch support and tree stability. Cladistics 10:295-304.

Gobloboff, P.A. 1993. Estimating character weights during search. Cladistics 9:83-91.

Goloboff, P.A., J.Farris & K. Nixon. 2003. Tree Analisis using new technology, ver 1.1. Program and documentation at http:// www.zmuc.dk/public/phylogeny/tnt.

Platnick, N.I. 1979. Phylosophy and the transformation of cladistics. Syst. Zool. 28:537-544.

22 de septiembre de 2009

BOTANY 2010, Rhode Island


Botany 2010
Call for Symposia, Colloquia, and Workshops
Overview
BOTANY 2010 will be held at Providence, Rhode Island, July 31 – August 4, 2010.

Societies participating in BOTANY 2010 will include:
  • the American Bryological and Lichenological Society (ABLS),
  • the American Fern Society (AFS),
  • the American Society of Plant Taxonomists (ASPT), and
  • the Botanical Society of America (BSA).

In preparation for Botany 2010 we are now soliciting proposals for symposia, colloquia, workshops, discussion sessions, and field trips. Symposia are organized around a topic of potential broad interest, are timely because of recent advances or synthesis in the field, or are particularly relevant to the conference venue. Colloquia are organized around more specialized topics with all presentations adhering to the standard 15 minute timeframe. The number of presentations in a colloquium is variable. Discussion sessions (“roundtable discussion”) are organized around a particular topic of interest with the bulk of the time devoted to discussion that engages the audience. Workshops are distinguished from symposia and colloquia by the inclusion of time devoted to hands-on activities (e.g., software demonstrations, data analysis tutorials, etc.).

websites
Call for Symposium - http://www.2010.botanyconference.org/2010Calls/2010ls_Symposia.php
Call for Workshops - http://www.2010.botanyconference.org/2010Calls/2010ls_Workshops.php

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