Question

What are three empirical examples of the Fisher-Zahavi Process (Combination)?

Answer 1

The Fisher-Zahavi Process describes how certain costly traits are favored by natural selection because they signal genetic fitness. Example of this process includes the evolution of peacocks' tail feathers, stotting behavior in gazelles, and the complex nests of bowerbirds, demonstrating transitions from basic to more elaborate traits for sexual selection advantages.

Step-by-step explanation:

The Fisher-Zahavi Process, also known as Zahavi's handicap principle or Fisher's runaway sexual selection, involves the concept that certain traits are favored by natural selection because they signal an underlying genetic advantage, even if the traits themselves may be costly to the organism. The combination mentioned in the task refers to a multi-step process involving several qualitatively superior substitutions or changes over time.

Here are three empirical examples that illustrate the Fisher-Zahavi Process:

1. Peacocks' tail feathers: The original state is a peacock with shorter tail feathers. The first replacement involves an evolution towards slightly longer and more colorful feathers, signaling health and strength, but also attracting predators. Finally, the second replacement is todays' peacock with extravagant tail feathers that are highly attractive to peahens, despite increasing the likelihood of predation.
2. Stotting in gazelles: Initially, gazelles might have only run away from predators. A superior first replacement is the introduction of stotting, where they jump high into the air, which seems to waste energy but signals to predators that the gazelle is healthy and not worth the chase. The further enhancement of this is the pronounced and consistent stotting when predators are nearby, further deterring pursuit.
3. Bowerbird nests: The basic state is a functional nest for attracting mates. The first improvement could be an incremental increase in the complexity and decoration of the nest to signal competence. The ultimate step in this process results in the creation of elaborately decorated and structured nests that reflect the male's superior building skills and resource-acquiring abilities.

These examples demonstrate how the Fisher-Zahavi Process operates in nature by showing the transition from simple to more complex or costly traits that ultimately benefit an organism through sexual selection.