Question

In the case of peppered moth (Biston betularia) the black-coloured form became dominant over the light-coloured form in England during industrial revolution. This is an example of

• A. appearance of the darker coloured individuals due to very poor sunlight
• B. protective mimicry
• C. inheritance of darker colour character acquired due to the darker environment
• D. natural selection whereby the darker forms were selected

Hint:

Natural selection refers to the mechanism by which populations of living organisms adapt and adjust to the environment. 

Answer 1

The Correct Option is D

The question revolves around the case of the peppered moth (Biston betularia) and how its black-coloured form became dominant over the light-coloured form during the industrial revolution in England. This phenomenon is a classic example used in evolutionary biology to illustrate natural selection.

To understand why the black-coloured form became dominant, let's break down the options given:

1. Appearance of the darker coloured individuals due to very poor sunlight: This is incorrect. The appearance of darker forms is not attributed to sunlight but is related to genetic variation and natural selection.

2. Protective mimicry: While mimicry involves organisms resembling other organisms or objects to avoid predation, this scenario reflects a change due to environmental conditions and differential survival, which is not merely mimicry.

3. Inheritance of darker colour character acquired due to the darker environment: Acquired characteristics (changes during an individual's lifetime) are not inherited genetically. The black coloration is a genetic trait, not an acquired one.

4. Natural selection whereby the darker forms were selected: This is the correct answer. During the industrial revolution, soot from factories darkened tree trunks and other surfaces. The light-coloured moths, which were once well-camouflaged against lichen-covered trees, became more visible to predators. Conversely, the black-coloured moths, which were previously more visible, now had a survival advantage in this new environment, allowing them to reproduce more successfully.

In summary, the black-coloured form of the peppered moth became dominant due to natural selection. The environmental changes caused by industrial pollution altered the selective pressures on the moths, favoring those that were less visible to predators in the soot-covered landscapes.