Lesson 2.5: How Do Organisms Reproduce?
|Issue||Naive Idea||Scientific Idea|
|Chromosome Pair||The "X" structures seen in metaphase of mitosis and metaphase II of meiosis are pairs of chromosomes.||The "X" structures seen in metaphase of mitosis and metaphase II of meiosis are individual replicated chromosomes. The tetrads seen in prophase I and metaphase I of meiosis are pairs of replicated chromosomes.|
|Chromosome Pairing||Chromosome pairing occurs in mitosis.||Chromosome pairing occurs only in meiosis.|
|Cell Division Cycle||Meiosis is cyclic.||Mitosis is cyclic (the process of meiotic cell division keeps repeating). Meiosis in contrast is unidirectional. The gametes either enter into fertilization or die.|
|DNA Replication||There are two rounds of cell division and therefore two rounds of DNA replication in meiosis.||There is one round of DNA replication followed by two rounds of cell division in meiosis; this reduces the chromosome number from diploid (usually) to haploid.|
* A misconception or alternative idea has three primary features: it is a cognitive idea that differs in a significant way from the scientific idea, it is held by a sizable proportion of the population, and it is notably resistant to being taught away; it is often described as a conceptual primitive (Clement, 1982). There are many other types of errors in understanding besides misconceptions (Fisher & Lipson, 1986).
Clement, J. (1982). Students' preconceptions in introductory mechanics. American Journal of Physics, 50 (1), 66 - 71.
Fisher, K. M. & Lipson, J. I. (1986). Twenty questions about student errors. Journal of Research in Science Teaching, 23 (9), 783-803.