Evolution – Solutions

1. Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.

Solution:

The Darwinian theory of natural selection prophesises survival of the fittest. Organisms that inherit the desirable characteristics are better suited in the environment and the less suited ones are weeded out. In other words, animals that are successful in the competition for existence are selected by nature.

Genetic variations and mutations are responsible for the development of new characteristics. The desirable characteristics are inherited, and the accumulation of such characteristics over time may lead to the evolution of new species.

This process is evident in the antibiotic resistance shown by bacteria. When bacteria were grown on an agar plate containing antibiotic penicillin, most of the colonies perished, but for a few. The bacteria that survived had developed a resistance to the antibiotic due to mutations. Later, they grew and increased in number.