As the kids straggle in, I look at Drosophila manuals : Kaufman, R.P. Drosophila Guide (8th ed.) 1969 ... In short order, she has a diagram sketch on the board and has raised the concepts: chromosomes, gene, double chromatid, tetrad, chiasmata, ... And later: Meiosis always requires two successive cell divisions, so that from each diploid cell that enters meiosis always a quartet of monoploid cells results.
|Title||:||Case Studies in Science Education: The case reports|
|Author||:||Robert E. Stake, J. A. Easley, Clifford J. Anastasiou|