AP BIOLOGY

Detailed explanation-1: -Giraffes with longer necks are better able to reach more food, survive and produce more high-quality offspring. Giraffes with short necks starved, didn’t reproduce. Hence, option (D) is the correct answer.

Detailed explanation-2: -Long necks enable giraffes to feed on leaves beyond the reach of competitors. But they are also deployed during tussles for dominance, when males swing their armoured heads at each others’ bodies, with the neck serving as the long handle of a club, increasing the force of the blow.

Detailed explanation-3: -According to Lamarck, the giraffe got its long neck because its ancestors stretched theirs to eat leaves that were just out of reach. This stretching of the neck was passed on to their offspring, over generations, until it reached its current length.

Detailed explanation-4: -Because they could access food, the giraffes with longer necks were better able to survive and reproduce, with their offspring inheriting their long necks.

Detailed explanation-5: -Charles Darwin was the first to propose that giraffes evolved into the elegantly long-necked creatures they are because successive generations realised that extra vertebrae helped them get access to tender leaves on top of trees.