Question

(05.01 hc)
read through the following observations.

1. some snakes have pelvic bones that sometimes sprout protrusions called \pelvic spurs,\ which serve little purpose
2. paleontologists have found the remains of an extinct, aquatic, snake-like lizard with miniature vestigial forelimbs
3. whales and some dolphins are marine mammals with hip bones that serve no purpose.
4. a dolphin was found that developed small hind flippers

based on these observations, what generalization can you make about the evolution of these animals?
○ whales and snakes have been evolving to be similar to walking animals
○ whales and snakes most likely evolved from snake-like marine lizards
○ whales are more closely related to snakes than to other marine mammals
○ whales and snakes must have evolved from four - legged animals.

Explanation:

Vestigial structures (pelvic spurs in snakes, hip bones in whales/dolphins, vestigial forelimbs in extinct aquatic snake - like lizard) are remnants of organs or structures that had a function in an early ancestor. The presence of these vestigial structures related to limbs (pelvic spurs, hip bones which are related to limb attachment in four - legged animals) suggests that whales and snakes had ancestors with four legs.

• Option 1: There is no indication that whales and snakes are evolving to be like walking animals. The vestigial structures are remnants of the past, not an indication of current evolution towards a walking form.
• Option 2: There is no evidence in the given observations to suggest that whales and snakes evolved from snake - like marine lizards. The observations only talk about vestigial structures in different animals.
• Option 3: There is no basis in the given data to claim that whales are more closely related to snakes than to other marine mammals. The focus is on vestigial structures related to limbs, not on the degree of relatedness between whales and snakes versus other marine mammals.

Answer:

Whales and snakes must have evolved from four - legged animals.