Question

Choose the correct answers from the alternatives given.
Darwin believed that a giraffe has a long neck because
A. God designed it that way.
B. Catastrophes eliminated short-necked forms.
C. Its ancestors stretched their necks to get food.
D. Ancestral giraffes with slightly longer necks got more food than others and left more surviving offspring.

Answer 1

As we have learnt that Darwin’s theory of Evolution explained about organism’s development through the natural selection of inherited variation, which increases the individual's ability to compete, survive, and reproduce.

Complete answer:
According to Lamarck’s theory: Previously, giraffes were more likely than not wound up in an environment where they experienced issues arriving at food present on the highest points of trees. So as to eat, they more likely needed to extend their necks and in doing so genuinely stretched their neck. This longer neck was adapted as a natural habit and acquired through the regular use which is passed onto the offspring in the next generation, who in turn stretched their necks even further which resulted in having very long necks in the giraffes species.
According to Darwin: Due to natural variation, the ancestors of modern giraffes have necks of different length.
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.

Additional Information:
Lamarck’s theory – It is about use and disuse of features. Giraffes inherited long necks from short necked ancestors who continually stretched their necks to reach their food.
Darwin’s theory explains the fact about the survival of the fittest. Long necked and short necked giraffes once existed together, but long-necked giraffes had an adaptive advantage, therefore survived and produced more high-quality offspring.

Note:

LAMARCK	DARWIN
No variations	Variations
Organisms can change according to environment	Environment selects for certain variations
An internal vital force in all organisms is seen	There is no any internal vital force in all organisms
All organisms survive	Not all organisms survive