Teoria de leon croizat biography

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Teoria de leon croizat biography

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Toggle the table of contents. Leon Croizat 16 July As an alternative to Darwinism, Croizat proposed the biological synthesis known as panbiogeography. This evolutionary framework rested on the foundations of biogeographic analysis to understand species, speciation, and biological differentiation in space, time, and form as a single synthesis rather than as the disparate conglomeration of disconnected hypotheses exemplified in Darwinism.

Adopting the term orthogenesis, Croizat, like Rosa and other biologists before him, viewed the generation of novel variation as a process biased by the existing genetic and developmental types of organization. Adaptation was seen as a consequence of evolution rather than a cause, and his orthogenetic approach eliminated the unscientific narrative approach to evolution prevailing then, as now, in Darwinian teoria de leon croizat biography that explains the origin of an adaptation by its ability to meet a future goal such as the resulting advantage or utility.

He proposed a biogeographic context for the origins of modern humans along a sector ranging between South Africa, Europe, and East Asia, which contrasted to Darwinian notions of an original birthplace followed by a concerted and sequential outward dispersal. In the s, he also produced a comprehensive analysis of the biogeographic origins of American Indians that anticipated current theories by proposing seafaring colonization coastal theory by people who were not modern Asians in appearance now implicated in studies of skulls such as the Kennewick Manand arrival before the Clovis culture upward of 40, years ago that compares well with the 20, now predicted by some anthropologists.

To explain disjunct distributions, Croizat proposed the existence of broadly distributed ancestors that established their range during a period of mobilism, followed by a form-making process over a broad front. Disjunctions are explained as extinctions in the previously continuous range. Orthogenesis is a term used by Croizat, in his words " Croizat considered organism evolution as a function of time, space and form.

Of these three essential factors, space is the one with which biogeography is primarily concerned. However space necessarily interplays with time and form, therefore the three factors are one of biogeographic concern. Put another way, when evolution is considered to be guided by developmental constraints or by phylogenetic constraints, it is orthogenetic.

Some researchers consider Croizat as one of the most original thinkers of modern comparative biology, whose contributions provided the foundation of a new synthesis between earth and life sciences. In the s, Croizat left Italy and first traveled to the United States before settling in Venezuela. He established the Botanical Garden in Caracas and became its director.

From onwards, Croizat served as a professor of botany and ecology at the University of the Andes.