Comparing the two
With both of them seen, they are easy to set side by side. There are six main differences.
| Meiosis | Mitosis |
|---|---|
| Consists of two divisional stages. | Consists of one divisional stage only. |
| Takes place only in diploid cells. | Takes place in haploid as well as diploid cells. |
| Variations arise; that is, changes occur in the chromosomes. | Variations do not arise; changes in the chromosomes are very rare. |
| Four daughter cells are formed at the end of the division. | Two daughter cells are formed. |
| The daughter cell receives half the chromosome number of the mother cell. | The chromosome number of the daughter cells equals that of the mother cell. |
| The daughter cells are not identical to the mother cell. | The daughter cells are identical to the mother cell in every respect. |
The table does not have to be memorised
All six rows come from one fact: meiosis happens in two stages and mitosis in one. That is why meiosis yields four cells and mitosis two; and it is why meiosis yields half the chromosomes and mitosis the full number.
Do not mix up the two names
Meiosis is the one that reduces the chromosome number — it is a reduction division. Mitosis does nothing to the chromosome number at all. One halves it, the other leaves it alone.
Pulling the chapter together
The way from the compartments Hooke saw to the chromosomes in a gamete runs along a single thread: the cell is the unit of life; each of its parts has a function; and the only way a new cell is ever obtained is by the division of one that already existed.