Question

Which of the following situations is in Hardy–Weinberg equilibrium?
A. A small number of fish can be found in a man-made pond at Hawrelak Park.

B. In a large population of E. coli bacteria, some are demonstrating resistance to penicillin.

C. Biosphere 2 is a closed ecological system located in Arizona.

D. An isolated population of caribou has been found on Baffin Island.

Answer 1

The conditions required for the existence of Hardy-Weinberg equilibrium are:

• Large breeding population
• Absence of selection
• Random mating
• No change in allelic frequency
• No migration

Hence, the correct option is (C) i.e, the biosphere 2 located in Arizona is likely to exist in Hardy - Weinberg equilibrium, since it conforms to all of the above necessary conditions. Being a biosphere, it must be containing a large interbreeding population, and being closed, there is no chance of migration too.

Other options are incorrect because;

• (A)- consists of a small population.
• (B)- population with the presence of antibiotic resistance will be naturally selected.
• (D) - there is a chance of change in allele frequencies in an isolated population.