Differentiate homologous and analogous structures with mammal examples.

Differentiate homologous and analogous structures with mammal examples.

• A. Analogous structures share a common ancestry; Homologous structures perform similar functions but arose independently (e.g., wings of bats vs birds).
• B. Homologous structures share a common ancestry; Analogous structures perform similar functions but arose independently.
• C. Homologous structures are unique to each species; Analogous structures are identical in form.
• D. Homologous structures are vestigial; Analogous structures are fully formed.

Answer: (B)

The idea here is about how evolution shapes anatomy based on ancestry. Homologous structures come from a shared ancestor, even when their current roles differ. In mammals, the forelimbs of humans, cats, whales, and bats all share the same basic bone plan—humerus, radius and ulna, carpals, metacarpals, and phalanges—because they inherited this arrangement from a common mammalian ancestor. Over time, those limbs were adapted for different functions: grasping, walking, swimming, and flying. Analogous structures, by contrast, perform similar tasks but didn’t arise from the same ancestral structure. They evolved separately to meet similar needs. A classic example is flight in different groups of animals; the wings of bats and the wings of birds serve the same purpose but have different evolutionary origins and internal bone arrangements. So, the correct idea is that homologous structures share a common ancestry, while analogous structures perform similar functions but arose independently.

The idea here is about how evolution shapes anatomy based on ancestry. Homologous structures come from a shared ancestor, even when their current roles differ. In mammals, the forelimbs of humans, cats, whales, and bats all share the same basic bone plan—humerus, radius and ulna, carpals, metacarpals, and phalanges—because they inherited this arrangement from a common mammalian ancestor. Over time, those limbs were adapted for different functions: grasping, walking, swimming, and flying.

Analogous structures, by contrast, perform similar tasks but didn’t arise from the same ancestral structure. They evolved separately to meet similar needs. A classic example is flight in different groups of animals; the wings of bats and the wings of birds serve the same purpose but have different evolutionary origins and internal bone arrangements.

So, the correct idea is that homologous structures share a common ancestry, while analogous structures perform similar functions but arose independently.