Biology Lessons Part 2: Population Biology


Lesson 2.5: How Do Organisms Reproduce?

Alternative Ideas

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.