classic example of adaptive radiation highlighted by Charles Darwin is the
A. extinction of two species of giant tortoises.
B. evolution of light to dark peppered moths.
The Correct Answer and Explanation is:
The correct answer is neither A nor B from the options you gave, but the classic example of adaptive radiation highlighted by Charles Darwin is actually the finches of the Galápagos Islands (often called “Darwin’s finches”).
However, since the options you provided are:
- A. extinction of two species of giant tortoises
- B. evolution of light to dark peppered moths
Neither accurately represents adaptive radiation as Darwin described it.
Explanation:
Adaptive radiation is the process by which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.
The classic example, famously studied by Charles Darwin during his voyage on the HMS Beagle, is the finches on the Galápagos Islands. These finches evolved from a common ancestor but diversified into multiple species, each adapted to different food sources and ecological niches on the islands. Some finches developed strong, thick beaks for cracking seeds, while others had slender beaks for catching insects or feeding on nectar.
- Option A (extinction of two species of giant tortoises) does not describe adaptive radiation but rather extinction, which is the disappearance of species.
- Option B (evolution of light to dark peppered moths) refers to industrial melanism, a classic example of natural selection but not adaptive radiation. The peppered moth case shows how populations can shift in traits due to environmental pressures (pollution darkening trees), but it is a change within a single species, not the diversification into multiple new species.
Why Darwin’s finches exemplify adaptive radiation:
- They descended from a single ancestral species.
- They diversified into several species with distinct beak shapes and sizes.
- Each species adapted to a specific ecological niche.
- This diversification is driven by competition for resources and environmental conditions.
Therefore, the adaptive radiation highlighted by Darwin is the diversification of finch species in the Galápagos Islands, not the extinction of tortoises or the color change in moths.
