According to Lamarckism, long necked giraffes evolved because

Options

A. nature slected only long necked ones
B. humans preferred only long necked ones
C. short necks suddenly changed into long necks
D. of strethcing of necks over many generations by short necked ones.

Explanation

**Step-by-Step Text Solution:**

1. **Introduction to Lamarckism**: Lamarckism is a theory of evolution proposed by Jean-Baptiste Lamarck, which suggests that organisms evolve through the use and disuse of organs. According to this theory, characteristics acquired during an organism's lifetime can be passed on to its offspring.

2. **The Case of Giraffes**: Lamarck used giraffes as a primary example to illustrate his theory. He posited that ancestral giraffes had shorter necks, similar to horses, and lived in environments where food was scarce and primarily located in tall trees.

3. **Stretching of Necks**: In order to reach the higher vegetation, these ancestral giraffes began to stretch their necks. This behavior of stretching was a response to their environment, where the available food supply was limited to higher branches.

4. **Inheritance of Acquired Characteristics**: According to Lamarck, the continuous stretching of the necks over generations led to the development of longer necks in giraffes. He believed that this acquired trait (longer necks) would be inherited by their offspring.

5. **Conclusion**: Therefore, according to Lamarckism, the long necks of modern giraffes evolved because their short-necked ancestors stretched their necks over many generations to reach food in higher vegetation. This characteristic was then passed down to future generations.

6. **Critique of Lamarckism**: It is important to note that Lamarck's theory has been largely discredited in favor of Darwin's theory of natural selection, which emphasizes that traits that provide a survival advantage are more likely to be passed on, rather than acquired traits.