Question

Over the past 60 years, many amphibian species have experienced significant population declindes, and some species have become extinct. Scientists suspected that local human activities such as destruction of wetlands, pollution, and deforestation were the main reasons for the losses. However, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks.

1. (2 pts) One solution to increase the number of individuals among threatened amphibian species is through captive-breeding programs where thousands of individuals could be produced from just a few of the remaining natural survivors. What affect would captive breeding have on amphibian populations? What could happen to allele frequencies?
2. (3 pts) Chytridiomycosis is a fungal disease that caused massive amphibian deaths in the late 1990s. In some populations, only a few individuals survived. Explain why these individuals were able to survive (make sure to mention the role of genes and alleles), and how this survival likely affected allele frequencies in the population.

Answer 1

1. Captive breeding on amphibian species will significantly increase the number of population and the allele frequencies of surviving population will have many fold increase and the allele variants will significantly reduce so that selection pressure upon some environmental change also can kill all the population produced by captive breeding.  

2. The individual survived in amphibians after infection will have the resistant and fittest allele and other allele frequency would have decreased and also offspring produced from resistant allele cross will also be resistant to chytridiomycosis