Autor Tópico: Árvores filogenéticas, antes de Darwin  (Lida 965 vezes)

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Árvores filogenéticas, antes de Darwin
« Online: 22 de Maio de 2010, 19:36:49 »
Acho bem interessante como, apesar de Agassiz ser "obrigado" a traçar uma genealogia dos seres, ele ainda assim se recusa a considerá-los como descendentes de um ancestral comum, criando um diagrama em árvore, mas no qual os galhos, ao se aproximarem uns dos outros, apenas se aproximam, sem nunca se "tocar", sem que nunca um tenha dado origem ao outro.






O artigo está ainda visível no cache do google (do visualizador de pdf do google), mas não é possível baixar o PDF.

O abstract:

Citar
Edward Hitchcock’s Pre-Darwinian (1840) ‘‘Tree of Life’’

J. DAVID ARCHIBALD
Department of Biology
San Diego State University
San Diego, CA 92182-4614
USA
E-mail: darchibald@sunstroke.sdsu.edu
Abstract. The ‘‘tree of life’’ iconography, representing the history of life, dates from
at least the latter half of the 18th century, but evolution as the mechanism providing
this bifurcating history of life did not appear until the early 19th century. There was
also a shift from the straight line, scala naturae view of change in nature to a more
bifurcating or tree-like view. Throughout the 19th century authors presented tree-like
diagrams, some regarding the Deity as the mechanism of change while others argued
for evolution. Straight-line or anagenetic evolution and bifurcating or cladogenetic
evolution are known in biology today, but are often misrepresented in popular
culture, especially with anagenesis being confounded with scala naturae. Although
well known in the mid 19th century, the geologist Edward Hitchcock has been
forgotten as an early, if not the first author to publish a paleontologically based ‘‘tree
of life’’ beginning in 1840 in the first edition of his popular general geology text
Elementary Geology. At least 31 editions were published and those between 1840 and
1859 had this ‘‘paleontological chart’’ showing two trees, one for fossil and living
plants and another for animals set within a context of geological time. Although the
chart did not vary in later editions, the text explaining the chart did change to reflect
newer ideas in paleontology and geology. Whereas Lamarck, Chambers, Bronn,
Darwin, and Haeckel saw some form of transmutation as the mechanism that created
their ‘‘trees of life,’’ Hitchcock, like his contemporaries Agassiz and Miller, who also
produced ‘‘trees of life,’’ saw a deity as the agent of change. Through each edition of
his book Hitchcock denounced the newer transmutationist hypotheses of Lamarck,
then Chambers, and finally Darwin in an 1860 edition that no longer presented his
tree-like ‘‘paleontological chart.’’

 

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