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Difficulty: MediumEvidence for Evolution: Comparative Anatomy, Embryology, and Vestigial Organs

The forelimb of a burrowing mole and the wing of a bat share the same fundamental pentadactyl skeletal framework despite being modified for completely different functions. Which of the following conclusions is best supported by this comparative anatomical evidence?

  1. The structures are homologous, providing evidence of divergent evolution from a common ancestor.Answer
  2. B
    The structures are analogous, indicating convergent evolution driven by similar environmental pressures.
  3. C
    The structures are vestigial, representing non-functional evolutionary remnants of past ancestors.
  4. D
    The structures are homoplastic, having arisen independently without any inherited developmental similarity.

Answer

The structures are homologous, providing evidence of divergent evolution from a common ancestor.
The forelimb of a mole and the wing of a bat possess the same basic pentadactyl skeletal layout (humerus, radius, ulna, carpals, metacarpals, and digits). Shared internal anatomy with distinct functional adaptations is the hallmark of homologous structures, which serve as strong evidence for divergent evolution from a common vertebrate ancestor.

Step-by-Step Solution

1
Analyze the anatomical features described in the stem.
The mole forelimb and bat wing share an underlying pentadactyl bone structure (humerus, radius, ulna, carpals, metacarpals, phalanges), indicating a shared embryonic and evolutionary origin.
Structures with a shared fundamental architecture derived from a common ancestor are classified as homologous.
2
Evaluate the functional differences between the two structures.
The mole forelimb is adapted for digging in soil, whereas the bat wing is adapted for flight in air.
Different selection pressures in distinct habitats cause homologous structures to diverge functionally.
3
Deduce the evolutionary pattern demonstrated by these structures.
Shared ancestry leading to different functional adaptations represents divergent evolution.
Divergent evolution explains how basic ancestral structures become modified for specialized ecological roles.

Key Concept

Homologous Structures and Divergent Evolution
Estimated Time:1m 0s
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Topics

Evidence for Evolution: Comparative Anatomy, Embryology, and Vestigial Organs

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