Question

For small population of endangered desert rodent, major concern for species survival is posed when

A. The frequency of mutation increases in small populations.

B. Natural selection can’t occur in a small population

C. Polyploidy is almost always lethal in higher vertebrates

D. There is a lack of natural resources in the desert

E. Recessive alleles become homozygous more frequently in small populations

Answer 1

The smaller populations are characterised by having a limited gene pool. If the population size is very small, there is more chance of inbreeding and species may become extinct.

Complete step by step answer:
Hardy Weinberg equilibrium is a feature of a non-evolving population which is practically absent in nature. Every population evolves which may be at different rates. Factors affecting this equilibrium are natural selection, mutation, gene migration, recombination, and genetic drift. In small populations, there is a chance for change in allele frequencies due to chance factors. These occur rapidly in small reproductively isolated populations. This phenomenon is called genetic drift and redistribution of allelic frequencies occurs here. This occurs faster in small populations as the gene pool is smaller compared to the larger populations. Inbreeding is a phenomenon in which genetically closely related species mates together and produce offspring. As the gene pool is limited in smaller populations, there is more chance for recessive alleles to show up and this becomes homozygous more frequently. So, in a small population, there is more chance for the defected and mutant alleles to show up as homozygous recessive individuals and causes an immediate threat to the stability of the population.

Hence, the correct option is E.

Note: Genetic drift and the process of inbreeding poses a great threat to smaller populations. Both prevent species diversity by changing the allele frequency. In genetic drift, the original population may be minimized to a small group called founder. It can evolve to become new species. This phenomenon is called the founder effect.