Question

In which way(s) does urbanization increase genetic drift (select all that apply)?

Environmental changes leading to an increase in genome-wide mutation rates

New populations establishing themselves in the urban environment leading to a founder effect

High number of roads in urban environment, cutting habitats in smaller fragments

Novel selective pressures in the environment such as pollutants leading to bottlenecks

Answer 1

All that apply are-

2) New populations establishing themselves in the urban environment leading to a founder effect

Explanation- Founder effect is the strong case where genetic drift is seen. Here new populations will be formed due to fragmentation of the area, as a result random decrease or increase in the allelic frequency in a particular population will result, thus increasing allele frequency of that allele most commonly present.

3)High number of roads in urban environment, cutting habitats in smaller fragments

Explanation- the habitats cut into smaller fragments on random will again lead to founder effect , where a new population might have organims of a particular genotype randomly , leading to increase in the allele frequency of one allele and decrease of other, thus resulting in genetic drift. Due to small population size the genetic drift will be stronger also.

4)Novel selective pressures in the environment such as pollutants leading to bottlenecks

Explaination- Bottleneck effect is a type of extreme genetic drift, where large no. Of population would be wiped out due to selective pressures etc and few random organisms will survive more likely having one of the allele with more frequency in population than the other.