Runaway selection was proposed by R.A. Fisher to explain the evolution of extravagant secondary sexual characters. The model is based on the exaggeration of characters in males and female choice for these exaggerated characters. Which one of the following statements is considered an assumption of this model?

Correct option is A

The runaway selection model proposed by R.A. Fisher assumes that both the exaggerated traits in males and the female preference for those traits are heritable. Fisher suggested that there is a genetic correlation between the male traits and female preference, which leads to a positive feedback loop where both traits become increasingly exaggerated over generations.

Information Booster:

1. Runaway selection theory focuses on the interaction between male traits and female preference, where both traits are selected for over time.
2. Heritability is key to the model, as both the exaggerated traits in males and the choosiness of females are passed on to offspring.
3. Genetic correlation between the two traits (exaggerated traits and female preference) causes the process of runaway selection to continue.
4. The feedback loop is crucial in runaway selection, as the male traits get more exaggerated, and females preferentially choose those traits, reinforcing the process.
5. The theory helps explain the development of seemingly excessive and costly traits in males, such as the peacock's tail.
6. Runaway selection can explain the divergence of traits between sexes and why some traits become so extreme, despite being costly to survival.

Additional Information:

• Option (b) - Neither exaggeration of characters in males, nor female choosiness for exaggeration are heritable: This is incorrect because runaway selection relies on the heritability of both the exaggerated traits in males and female preference.

• Option (c) - Exaggeration of characters in males is heritable but female choosiness for exaggeration is not heritable: This option is incorrect because, according to Fisher's model, both male traits and female choosiness must be heritable for runaway selection to occur.

• Option (d) - Exaggeration of characters in males is not heritable but female choosiness for exaggeration is heritable: This is incorrect as well because, for runaway selection to work, both male traits and female preference must be genetically linked and heritable.