Question

In many bird species, sex is preceded by a courtship dance. If a male's dance is unrecognized by the female, she will not mate with him. This is an example of _____. a. a sexual dimorphism b. disruptive selection c. sexual selection d. coevolution

Short answer

This is an example of sexual selection.

Step-by-step solution

Clarifying the Concepts

To solve the problem, we need to identify what each term means in biology. - **Sexual dimorphism** refers to differences in appearance between males and females of the same species. - **Disruptive selection** is a type of natural selection that selects against the average individual in a population. - **Sexual selection** is the process by which certain traits increase an individual's chances of mating and reproducing. - **Coevolution** occurs when two or more species interact closely and evolve together.

Analyzing the Scenario

The scenario describes a situation where a male bird performs a courtship dance. If the dance is recognized as favorable by the female, she will choose to mate, otherwise, she will not. This indicates a preference or selective process based on male behavior.

Matching Scenarios to Terms

- **Sexual dimorphism** does not fit because the problem deals with behavior, not physical appearance. - **Disruptive selection** is not suitable because the situation does not refer to selection against an average trait. - **Sexual selection** fits well, as it involves a selection process based on traits (such as a dance) that affect mating success. - **Coevolution** is not applicable as it involves mutual evolutionary influence between species, not individuals of the same species.

Selecting the Correct Answer

Given the information, the behavior and selection process described are best explained by sexual selection, where traits that are favorable for mating, such as a recognizable dance, are selected for.

Key concepts

Courtship Behavior

Courtship behavior is a fascinating aspect of animal interactions often linked to reproduction. In many species, individuals must perform specific actions to attract a mate. These actions can range from dances and vocal calls to creating intricate structures. These behaviors serve as signals that can indicate a variety of factors such as the health, strength, and genetic quality of the individual. For example, in birds, a male may perform an elaborate dance to win over a female. This dance is not just for show; it communicates his fitness as a potential mate.
Courtship behaviors are crucial in the mating process and often determine who will mate with whom. It ensures that those with the best traits, as demonstrated through their behavior, are those who pass on their genes. This behavior often develops through sexual selection, and the species that engage in complex courtship rituals tend to show high levels of competition among males for access to females.

Mate Choice

Mate choice is a critical element in the theory of sexual selection, where individuals have criteria or preferences when choosing a partner for reproduction. This choice is primarily observed in the female of the species, although not exclusively. Females might select males based on traits that signal good genes, such as vibrant plumage or a strong vocal display. These traits indicate a male's overall fitness and capability to produce healthy offspring.
The process of mate choice affects the dynamics of sexual selection as it can lead to heightened competition amongst individuals to possess the qualities deemed most attractive. Factors influencing mate choice can include genetic traits, behavioral displays, and even the ability to provide resources or protection. Thus, mate choice shapes the evolutionary path of a species by favoring traits that enhance reproductive success.

Mating Success

Mating success refers to the likelihood of an individual in successfully mating and producing offspring. It’s an important concept in the study of evolutionary biology and sexual selection. Mating success can be influenced by a variety of factors, including physical traits, behaviors, and social dynamics within a species.
For instance, in many species, males may develop distinct features or engage in specific behaviors to attract females, such as competing with other males or showcasing elaborate courtship rituals. Those who succeed in these efforts tend to have higher mating success and, consequently, better reproductive outcomes. High mating success is a driver of evolution, as traits that lead to successful mating are often passed on to future generations, thereby fostering adaptation and diversity within species.

Sexual Dimorphism

Sexual dimorphism is a striking outcome of sexual selection and refers to the differences in appearance and size between the males and females of a species. These differences can manifest in various ways, such as size, color, or the presence of ornamental features like antlers or crests. Often, sexual dimorphism results from the differing pressures male and female animals face in reproductive activities.
In many species, males evolve more pronounced features or vibrant appearances as a result of sexual selection, which are utilized to attract females or to compete with other males. For example, the elaborate plumage and bright colors of a male peacock are significantly different from the more subdued appearance of the female. These characteristics play a crucial role in mating rituals and mate selection, thus influencing evolutionary trajectories.

Coevolution

Coevolution describes the process where two or more species reciprocally affect each other's evolution. Unlike evolutionary changes that occur within a single species, coevolution involves interactions between species that can drive simultaneous evolutionary changes.
This phenomenon often occurs between predators and prey, parasites and hosts, or mutualistic pairs. For example, as a prey species develops better defenses, its predators must adapt to overcome these defenses, leading to a cycle of reciprocal evolutionary changes. While coevolution refers to species-specific interactions, it is not directly involved in intra-species sexual selection. However, it highlights the complex interplay of evolutionary forces that shape the diversity of life on Earth.