Findings on Sexual Dimorphism
Discussion:
The purpose of this lab was to compare average canine width and average bite force between male and female Arctic foxes (Vulpes lagopus) to determine if they are sexually dimorphic. The results showed that there is a statistically significant difference in female and male bite force as well as canine width. Males were found to have a larger bite force and canine width than that of females.
The evolutionary cause of sexual dimorphism in the Artic fox may be explained through three main hypotheses: sexual selection, food competition between the sexes, and the dimorphic niche. The dimorphic niche hypothesis proposes that sexual dimorphism might evolve from intrinsic differences between the reproductive roles of males and females (Hedrick and Temeles, 1989). For example, if males are primarily responsible for protecting their offspring, their role as a parent might explain for larger bite force and larger canine width than females.
Darwin’s sexual selection hypothesis proposes that sexual dimorphism evolves when characters that confer an advantage in either competition for mates or mate choice are selected for within one sex (Hedrick and Temeles, 1989). Bite force and canine width in the male Arctic fox may improve fighting ability and the ability to capture prey for food. In Lappin and Husak’s study of weapon performance in the Collard Lizard (Crotaphytus collaris), the male lizard tends to have a larger head than a female, and this male-biased head dimorphism is associated with combat. The head size of a male lizard can be related to territory and mating success. Selection acts on traits most relevant to fitness, therefore bite force and canine width are characteristics that may increase mating success. As dominance is an important component of fitness in nature, it is possible that sexual dimorphism evolved in the Arctic fox through female mating preferences for males with larger bite force and canine width.
Another hypothesis which may explain why
The purpose of this lab was to compare average canine width and average bite force between male and female Arctic foxes (Vulpes lagopus) to determine if they are sexually dimorphic. The results showed that there is a statistically significant difference in female and male bite force as well as canine width. Males were found to have a larger bite force and canine width than that of females.
The evolutionary cause of sexual dimorphism in the Artic fox may be explained through three main hypotheses: sexual selection, food competition between the sexes, and the dimorphic niche. The dimorphic niche hypothesis proposes that sexual dimorphism might evolve from intrinsic differences between the reproductive roles of males and females (Hedrick and Temeles, 1989). For example, if males are primarily responsible for protecting their offspring, their role as a parent might explain for larger bite force and larger canine width than females.
Darwin’s sexual selection hypothesis proposes that sexual dimorphism evolves when characters that confer an advantage in either competition for mates or mate choice are selected for within one sex (Hedrick and Temeles, 1989). Bite force and canine width in the male Arctic fox may improve fighting ability and the ability to capture prey for food. In Lappin and Husak’s study of weapon performance in the Collard Lizard (Crotaphytus collaris), the male lizard tends to have a larger head than a female, and this male-biased head dimorphism is associated with combat. The head size of a male lizard can be related to territory and mating success. Selection acts on traits most relevant to fitness, therefore bite force and canine width are characteristics that may increase mating success. As dominance is an important component of fitness in nature, it is possible that sexual dimorphism evolved in the Arctic fox through female mating preferences for males with larger bite force and canine width.
Another hypothesis which may explain why