Which one of the following is essential if speciation is to occur?

Question

1. Chromosome doubling

2. Interbreeding between populations or between polymorphisms is kept at a low level

3. Different selection pressure between populations

4. Occupation of a large range

5. Polymorphic breeding behaviour

6. Very high gene flow

Answer 1

Different selection pressure between two populations will cause speciation.  Without mutations, it is essential that pressure is applied to a species to cause evolution.  Without selection pressures there is no favorable genetic make up of the organsim, therefore speciation does not occur.

Answer 2

2. interbreeding between populations or between polymorphisms is kept at a low leval

Answer 3

Very high gene flow