Which of the following best characterizes an adaptive radiation? a. Descendant species occupy a large geographic area. b. A single lineage diversifies rapidly, and descendant species occupy many habitats and ecological roles. c. Natural selection is particularly intense, because disruptive selection occurs. d. Species recover after a mass extinction.

Verified step by step guidance

1. Step 1: Understand the concept of adaptive radiation. Adaptive radiation is an evolutionary process where organisms diversify rapidly from an ancestral species 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.
2. Step 2: Evaluate each option in the context of this definition. Option a, 'Descendant species occupy a large geographic area', is not necessarily indicative of adaptive radiation. While it's true that descendant species may spread out geographically, this is not the defining characteristic of adaptive radiation.
3. Step 3: Option b, 'A single lineage diversifies rapidly, and descendant species occupy many habitats and ecological roles', aligns well with the definition of adaptive radiation. This option describes the rapid diversification into new forms and the occupation of various ecological roles, which are key aspects of adaptive radiation.
4. Step 4: Option c, 'Natural selection is particularly intense, because disruptive selection occurs', is not necessarily indicative of adaptive radiation. While natural selection and disruptive selection can play roles in adaptive radiation, they are not the defining characteristics.
5. Step 5: Option d, 'Species recover after a mass extinction', is not necessarily indicative of adaptive radiation. While it's true that adaptive radiation can occur after mass extinctions when new niches become available, this is not the defining characteristic. Therefore, the best answer is option b.

Key Concepts

Adaptive Radiation

Adaptive radiation is an evolutionary process in which a single ancestral lineage rapidly diversifies into a wide variety of forms, each adapted to different environments or ecological niches. This phenomenon often occurs when species colonize new habitats or after significant environmental changes, allowing them to exploit various resources and reduce competition.

Natural Selection

Natural selection is a fundamental mechanism of evolution, where individuals with advantageous traits are more likely to survive and reproduce. This process leads to the gradual adaptation of species to their environments, influencing their physical and behavioral characteristics over generations. In the context of adaptive radiation, natural selection drives the diversification of species as they adapt to different ecological roles.

Ecological Roles

Ecological roles refer to the functions and positions that species occupy within an ecosystem, including their interactions with other organisms and their contributions to energy flow and nutrient cycling. In adaptive radiation, descendant species often evolve to fill various ecological roles, such as predators, herbivores, or pollinators, allowing them to coexist and thrive in diverse environments.