Question

There are two species of freshwater shrimp that are introduced to a pond. The first species, Caridina cantonensis, is brightly colored with red and white stripes. The second species, Caridina multidentata, is more mottled drab in coloration. Fish have an easier time finding and eating Caridina cantonensis due to their bright colors. When each of these species reproduce they produce about 100 offspring, but only 30% Caridina cantonensis offspring survive to reproductive age, while 75% Caridina multidentata offspring survive to reproductive age. In this situation what is natural selection selecting for? In this situation what is natural selection selecting against? How do you predict this population will evolve? Identify how each of the listed conditions from the above scenario that influence natural selection.

Answer 1

Explanation:

Natural selection is the mechanism that is responsible for the evolution of organisms.  

In the given case, the Freshwater shrimp has been introduced to a pond in which the two species with variations are introduced.  

The C. cantonensis is brighter in color whereas the C. multidentata is mottled drab in color. The predator fish can feed easily on the species which is brighter therefore C. cantonensis is more susceptible. The mottled drab species is not easily predated by the species.  

The 30 % offsprings of C. cantonensis can survive till the reproductive age  whereas 75% of C. multidentata. This shows that natural selection has acted on the color of the shrimp species selected against the predator fish species.

The species with mottled drab color is the result of the differential reproductive rate.