New species may be formed if :

Question

Accepted Answer

New species may be formed if the chromosome number changes in the gamete, as stated in Option 2. This is because changes in chromosome number can lead to reproductive isolation, which is a key factor in the formation of new species. When the chromosome number in gametes changes, it can result in offspring that are genetically distinct from their parent species. This genetic distinction can prevent the new offspring from successfully breeding with the original population, leading to the development of a new species over time.

Now, let's examine why the other options are incorrect:

1. DNA undergoes significant change in germ cell: While changes in DNA can lead to variations within a species, they do not necessarily result in the formation of a new species. Mutations in DNA can lead to new traits, but for a new species to form, these changes must lead to reproductive isolation, which is not guaranteed by DNA changes alone.

3. There is no change in genetic materials: If there is no change in genetic materials, there is no basis for the formation of a new species. New species arise from genetic variations that lead to differences significant enough to cause reproductive isolation. Without changes in genetic material, the population remains genetically similar, and no new species can form.

4. (A), (B) and (C): This option suggests that all the given scenarios could lead to the formation of a new species. However, as explained, only a change in chromosome number (Option 2) directly supports the formation of a new species through mechanisms like reproductive isolation. Options 1 and 3 do not independently lead to speciation.

In conclusion, Option 2 is the correct answer because a change in chromosome number in gametes is a direct and effective mechanism for the formation of new species through reproductive isolation and genetic divergence.