Question

The result of mitosis is that the daughter cells end up with the same number of chromosomes that the parent cell had. Another way to maintain the number of chromosomes would be to carry out cell division first and then duplicate the chromosomes in each daughter cell. Do you think this would be an equally good way of organizing the cell cycle? Why do you suppose that evolution has not led to this alternative?

Answer 1

No, it will not be good way of organizing the cell cycle, as cell division would occur first and duplicate the chromosomes later, it would lead to unequal distribution of chromosomes in the offspring.

E.g. let the parent cell has chromosomes A, B, C, D so when the cell will divide the chromosomes will be divided in two sets as: (A, B) and (C, D), the daughter cells will have one of these sets each. Later it will be duplicated then the result will be (A, A, B, B) and (C, C, D, D). But ideally it should be A, B, C, D, as this had not happened in the above case so the offspring or daughter cells would have half of the genetic code missing hence they could not survive in nature. That's why natural evolution had not led to this alternative.