El enfoque histórico contextualizado como facilitador de la enseñanza de los mecanismos evolutivos

Abstract

Se parte del supuesto que las ideas previas de los alumnos se constituyen en obstáculos para la enseñanza de los mecanismos evolutivos, se pone a prueba una unidad didáctica basada en un enfoque histórico confrontándola con otra unidad basada en resolución de problemáticas. Para realizar este estudio comparativo se tomó un pre-test en dos cursos de 3° año de secundario polimodal con orientación Ciencias Naturales para detectar concepciones previas, anteriormente categorizadas. Se analizaron las respuestas supuestamente “lamarckianas” y “darwinianas” en forma cuantitativa y cualitativa y se realizó observación participante en el seguimiento de las clases para evaluar el proceso de conceptualización y la construcción del discurso individual y grupal en cada uno de los cursos y un post test para confrontar los resultados. Se arriba a la conclusión que las estrategias de enseñanza basadas en un enfoque histórico facilitan el cambio representacional de una concepción “lamarckiana” de los mecanismos de resistencia y del modelo macroevolutivo a una “darwiniana” en alumnos de tercer año de secundario superior o polimodal, y pueden convertirse en una herramienta valiosa para la construcción del discurso mediante la enseñanza por medio de la argumentación. El alcance de esta tesis no solo fue de corroboración de ideas previas erróneas sino que aportó la construcción de una innovación didáctica incluyendo prescripciones con propuestas de estrategias que ayuden a superarlas.

The students´ previous conceptions about the mechanisms of evolution are similar in different countries. This was verified by different studies. From that onwards the “lamarckians” attribute is given to a group of recurrent preconceptions which appear in the students´ answers, those who face the understanding of the mechanism of evolution presented in the resolutions of problematic situations of adaptation when that requires an explanation of the implied mechanism of evolution. These ¨lamarkians" ideas are not well denominated because it implies the consideration of the evolution like a progressive lineal process and the mechanism of acquisition of structures by means of the use and disuse and the inheritance of the acquired characters. Admitting that these ideas constitute obstacles for the teaching learning of the mechanism of evolution, a didactic unit was designed based on a historical-epistemological approach, in the context of these problems to get over these obstacles. An investigation is designed to confront its effectiveness, comparing to another unit based on the resolution of problematic related to resistance cases and speciation proposed in the current bibliography. This comparative study to examine two courses with 3º year Natural Sciences orientation at High School is carried out to detect previously categorized conceptions. The "lamarckians" and "darwinians" answers were analyzed in quantitative and qualitative research work and there was a close participant observation of classes to evaluate the conceptualization process and the construction of the individual and group speech in each of the courses. It was observed that the ideas or previous representations of the students on both courses with regard to the mechanism of evolution were similar to each other and they agreed with the results of previous studies. The natural selection concept was the one that presented more obstacles. Those same obstacles were overcome in some situations, but not in others, depending on the examples, the problems, the context and the terminology used. In conclusion the historical focus favors the argument and the construction of the shared speech of the students and the educational one because it provides resources, testimonies, tests, counter-arguments that allow the dialogue and the debate to happen. Therefore, the teaching strategies based on a historical focus facilitate the representational change of a “lamarckian” conception of the resistance mechanisms and the macroevolutive pattern to a "darwinian" in 3º year High School students or Polimodal. The results can become a valuable tool for the construction of discourse due to teaching through argumentation. The outcome of this thesis was not only the corroboration of erroneous previous ideas but also contributed to the construction of a didactic innovation including prescriptions with proposals of strategies that may help to overcome the aforementioned obstacles.