Examkin

Question

Difficulty: Very hardAdaptive Radiation and Mechanisms of Speciation

An ancestral bird species colonized an isolated island chain containing diverse, unoccupied food sources. Over time, this single lineage gave rise to multiple distinct species, each exhibiting specialized beak morphologies for feeding on nectar, hard seeds, or insects, while retaining homologous limb structures. Which of the following processes best accounts for this pattern of speciation?

  1. Adaptive radiation resulting from natural selection exploiting diverse ecological nichesAnswer
  2. B
    Convergent evolution driven by unrelated lineages independently developing analogous feeding structures
  3. C
    Inheritance of acquired traits developed by individual birds through repeated beak use during foraging
  4. D
    Discontinuous variations occurring randomly without natural selection or reproductive isolation mechanisms

Answer

Adaptive radiation resulting from natural selection exploiting diverse ecological niches
Adaptive radiation occurs when a single ancestral species rapidly evolves into multiple distinct species, each adapted to fill different vacant ecological niches, while preserving underlying structural homologies.

Step-by-Step Solution

1
Identify the ancestral origin and structural homology
The birds originate from a single ancestral species and share homologous limb structures, confirming common ancestry and divergent evolution.
Homologous anatomical structures indicate descent from a shared common ancestor rather than unrelated origins.
2
Analyze ecological niche diversification
Multiple unoccupied food sources created distinct selection pressures, favoring specialized beak morphologies.
Ecological opportunity drives adaptive modification across different habitats.
3
Determine the overarching speciation mechanism
The rapid evolutionary diversification of a single lineage into ecologically distinct species occupying varied niches is defined as adaptive radiation.
Adaptive radiation is the primary mechanism of speciation observed in island archipelagos.

Key Concept

Adaptive Radiation and Mechanisms of Speciation
Estimated Time:1m 30s
Rate this question

Topics

Adaptive Radiation and Mechanisms of Speciation

More questions from this topic