Biology-cohort-heredity

=Planning the Unit= toc Below is a list of common misconceptions that teachers can be looking for during the unit. If you would like to contribute please add misconceptions that you have found and the reference or citation from which it came.

Common Misconceptions
There is reason to believe that students should have a clear understanding of the characteristics of life (living vs.non-living) before beginning a unit of reproduction, growth, and inheritance. In particular an understanding that includes living things as having the ability to grow and reproduce. Additionally, a clear distinction between sexual and asexual reproduction precludes an understanding of the origins of variation.


 * 1) The distinction between reproduction and the act of copulation in mammals should be made clear. For example, students often think that plants are incapable of sexual reproduction because they cannot copulate. (Driver, et al., 1994)
 * 2) Students may commonly hold the following misconceptions:
 * sexual reproduction must involve mating
 * male animals are always bigger and stronger that female animals
 * animals consciously plan their reproductive strategies
 * asexual reproduction results in weakness and sexual reproduction always produces stronger indivudals
 * hermaphroditism is the same as asexual reproduction (Driver, et al., 1994)
 * 1) Concerning twins, students often think that twins can be formed from one egg and two sperm or that identical twins can be of opposite sexes.(Driver, et al., 1994)
 * 2) Concerning variation between species, students often think that the variation is due to environmental factors rather than inheritance. Sexual reproduction is not recognized as the source of variation. Students do not understand the interaction between genes and the environment.(Driver, et al., 1994)
 * 3) 5. students often believe in the blending of traits from the parents and that one parent contributions can be "stronger" than other, typically the male contribution.(Driver, et al., 1994)
 * 4) Females inheritance is dominated by traits from the mother and male inheritance is dominated by traits from the father.(Driver, et al., 1994)
 * 5) Students know the word "gene" but less frequently know the word "chromosome" .(Driver, et al., 1994)
 * 6) Students understand little of the nature and function of genes and chromosomes and do not appreciate the chemical basis of inheritance.(Driver, et al., 1994)
 * 7) Students do not have a clear understanding of how chance plays a role in reproduction.(Driver, et al., 1994)

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Lesson Plans


If you think about the genetics unit, students first organized their knowledge about genetics and cell division into an initial concept map and then sought evidence that would move their thinking forward by observing cells in the process of dividing. Students did not think of observing cells on their own. They were "guided" to this experience by the teacher purposely. Once the data was collected, students generated new knowledge together through attempts to organize their pictures of cells into a process. The teachers role was to guide this discussion without "giving it away". Finally, scientific terminology was added to the model thus completing the modeling cycle. One additional activity that would be valuable would be to have students write about their model or use their model to explain a new question about cell division such as a question about the possible outcome of an error in chromosome assortment. This kind of question would allow them to use their model to make a prediction about a meaningful science concept.

Organizing What we Know and What we Don't Know

Building a model from data

http://bio.rutgers.edu/~gb101/lab2_mitosis/index2.html

Revising the model

=References=

Driver, R. Squires, A., Rushworth, P., Wood-Robinson, V. (1994). Making Sense of Secondary Science: Research into children's ideas. Routledge. New York.