AP BIOLOGY

Detailed explanation-1: -Q. Scientists think that dolphins and whales may have evolved from a common ancestor. What evidence supports this hypothesis? They swim the same way.

Detailed explanation-2: -Looking at a whale’s body and biology, there are plenty of clues that their ancestors lived on land. They breathe air and nurse their young with their own milk, they also have paddle-shaped flippers which encase hand bones with five ‘fingers’. As embryos, whales have tiny back limbs which disappear before birth.

Detailed explanation-3: -A 24-million-year-old fossil of a giant tusked dolphin lacks several features common to modern dolphins and baleen whales. The discovery shows that the common ancestor of dolphins and whales lacked these features, meaning the same adaptations for swimming must have evolved independently in both lineages.

Detailed explanation-4: -Multiple types of evidence support the theory of evolution: Homologous structures provide evidence for common ancestry, while analogous structures show that similar selective pressures can produce similar adaptations (beneficial features).

Detailed explanation-5: –Because whales lack a placenta, they must have evolved from a marsupial mammal (like a kangaroo or opossum) rather than from a placental mammal like a dog or a hippo.