Secondary sexual characteristics

Definition

Secondary sexual characteristics are physical traits that emerge during puberty and differentiate between the sexes but are not directly involved in reproduction. These features, which develop under the influence of sex hormones like testosterone and estrogen, contribute to the sexual dimorphism observed in humans and other species. Common examples include breast development in females, increased muscle mass in males, and changes in body hair distribution.

5 Must Know Facts For Your Next Test

1. Secondary sexual characteristics typically begin to appear during puberty, around ages 9-14 for girls and 10-17 for boys.
2. In males, increased testosterone levels lead to traits such as deeper voice, facial hair, and broader shoulders.
3. In females, estrogen influences breast development, wider hips, and a higher percentage of body fat compared to males.
4. These characteristics play a crucial role in social signaling and mate attraction within many species, including humans.
5. The expression of secondary sexual characteristics can vary widely due to genetic, environmental, and cultural factors.

Review Questions

• How do secondary sexual characteristics manifest differently in males and females during puberty?
  • During puberty, secondary sexual characteristics manifest differently due to the influence of sex hormones. In males, increased testosterone leads to traits such as a deeper voice, increased muscle mass, and facial hair growth. Conversely, females experience breast development and wider hips due to rising estrogen levels. These changes not only signify physical maturity but also play roles in social interactions and reproductive signaling.
• Discuss the role of hormones in the development of secondary sexual characteristics during adolescence.
  • Hormones play a pivotal role in the development of secondary sexual characteristics during adolescence. In males, testosterone drives the development of features like facial hair and a deeper voice. For females, estrogen is key for breast development and fat distribution patterns. The interplay between these hormones influences not only physical traits but also behavioral aspects related to mating and social dynamics.
• Evaluate the significance of secondary sexual characteristics in human evolution and social structures.
  • Secondary sexual characteristics have significant implications for human evolution and social structures by influencing mate selection and reproductive success. The visible differences between sexes can signal health and genetic fitness, guiding preferences in partner choice. Additionally, these traits can impact social roles within groups, contributing to cultural norms surrounding gender. As societies evolve, the understanding of these characteristics continues to shape perceptions of masculinity and femininity, illustrating their enduring relevance across human history.

Related terms

Sexual dimorphism: The differences in size, shape, or color between males and females of the same species, often associated with reproductive roles.

Puberty:

The period of physical development during which adolescents reach sexual maturity and experience various hormonal changes leading to the development of secondary sexual characteristics.

Hormones: Chemical messengers in the body that regulate physiological processes, including the development of secondary sexual characteristics through sex-specific pathways.