Which term describes structures in different species that are similar due to a common ancestor?

Which term describes structures in different species that are similar due to a common ancestor?

• A. Paleontologists
• B. Mold
• C. Trace Fossils
• D. Homologous Structures

Answer: (D)

Structures in different species that are alike because they come from a common ancestor are homologous structures. This means the parts have a shared internal plan even if they look different or do different jobs today. A classic example is the forelimbs of humans, cats, whales, and bats—they all have a similar arrangement of bones (like a humerus, radius and ulna, carpals, metacarpals, and phalanges) even though each limb is used for grasping, walking, swimming, or flying. This similarity points to descent from a common ancestor and shows how evolution can adapt a basic blueprint for different needs. Paleontologists are scientists who study fossils, mold is an impression left by an organism, and trace fossils are preserved signs of activity like footprints. These terms describe people or types of fossil evidence, not the shared anatomical relationships across species.

Structures in different species that are alike because they come from a common ancestor are homologous structures. This means the parts have a shared internal plan even if they look different or do different jobs today. A classic example is the forelimbs of humans, cats, whales, and bats—they all have a similar arrangement of bones (like a humerus, radius and ulna, carpals, metacarpals, and phalanges) even though each limb is used for grasping, walking, swimming, or flying. This similarity points to descent from a common ancestor and shows how evolution can adapt a basic blueprint for different needs.

Paleontologists are scientists who study fossils, mold is an impression left by an organism, and trace fossils are preserved signs of activity like footprints. These terms describe people or types of fossil evidence, not the shared anatomical relationships across species.