Question

What is adaptive radiation? Describe it with an example.

Hint:

Adaptive radiation = One species → Multiple species, adapting to various environments.
Example: Darwin's finches.

Answer 1

Adaptive radiation is an evolutionary process in which a single ancestral species rapidly diversifies into multiple descendant species, each adapted to occupy different ecological niches or environments. This phenomenon occurs when organisms encounter new or varied habitats, leading to the evolution of specialized traits that allow them to exploit specific resources or conditions. Adaptive radiation is a key mechanism driving biodiversity and is often observed in isolated environments like islands, lakes, or newly formed ecosystems.

Example of Adaptive Radiation

Darwin's Finches in the Galápagos Islands

Background: Charles Darwin observed a group of finch species on the Galápagos Islands during his voyage on the HMS Beagle. These finches are now famously known as "Darwin's finches."

Ancestral Species: A single finch species from mainland South America colonized the Galápagos Islands.

Diversification: Over time, the finches diversified into 14 distinct species, each adapted to a specific ecological niche:

• Ground Finches: Developed large, strong beaks for cracking seeds.
• Tree Finches: Evolved smaller, pointed beaks for probing flowers or catching insects.
• Warbler Finches: Developed slender beaks for feeding on small insects.
• Cactus Finches: Adapted to feed on cactus flowers and seeds with specialized beak shapes.

Driving Force: The isolation of the islands and the availability of diverse food sources (seeds, insects, nectar) led to natural selection favoring variations in beak size and shape.