Question

Sharks, whales, and dolphins share similar features such as body shape and the position of fins. However, sharks have gills for breathing, while

whales and dolphins have lungs. These differences indicate that the organisms share a common ancestor for
Whales also possess a vestigial pelvic bone. The presence of the pelvis bone may indicate that whales

Answer 1

Dolphins and fish have analogous traits, such as similar body shapes, due to convergent evolution from adapting to similar environments. The vestigial pelvic bones in whales also point to homologous traits indicating a terrestrial ancestry.

Step-by-step explanation:

The question pertains to evolutionary biology and examines the differences and similarities among sharks, whales, and dolphins in the context of their shared evolutionary history. Regarding the specific traits mentioned, dolphins and fish present a case of convergent evolution. This brings us to the analogy of analogous traits and homologous traits. An analogous trait is one that arises because species inhabit similar environments and face similar selective pressures, not because of a recent common ancestor. On the other hand, a homologous trait is due to a common ancestor. Therefore, even though both dolphins and fish are vertebrates, their similar body shapes are analogous because they have adapted to similar environments, not because they have a recent common evolutionary history. Conversely, the vestigial pelvic bone in whales suggests a homologous trait indicating evolution from a land-dwelling ancestor.