As a part of a larger study on the learning of natural selection by secondary school students in Spain, data were gathered about how textbooks deal with this topic, and about the ability of teachers to explore pupils' ideas related to it. These data were contrasted with an approach seeking to develop the pupils' capacity to explain biological change using the model of natural selection. Textbooks were analyzed with respect to the following characteristics: the way key ideas in the model were handled, the attention paid to pupils' ideas, and the type of activities used in the instruction. The study involved evaluating the above factors in a sample of 17 books used in Spain, as well as the approaches that teachers used. Results show that in most cases the approach is characterized by superficial handling of key ideas, lack of attention paid to alternative ideas, and little variety in activities. Relation between this approach and the difficulties that pupils show in the use of the model are discussed herein.
Mark what Jacob did When Laban and himself were compromis'd, That all the eanlings which were streak' d and pied, Should fall as Jacob's hire, the ewes, being rank, In end of autumn turned to the rams: and when the work of generation was Between these woolly breeders in the act. The skillful shepherd peel'd me certain wands, and, in the doing of the deed of kind, He stuck them up before the fulsome ewes, Who, then conceiving, did in earning time Fall party-colour''d lambs, and those were Jacob's.