Laboratory Report
Course #: BIOL1004A Lab #: 2
Sexual Dimorphism in Arctic Foxes
Kathryn Brechun
Date Performed: January 29, 2014
Date Submitted: February 12, 2014
Lab Period: Thursday AM
Station: B3
T.A: Genevieve Perkins
Abstract
Sexual dimorphism in the feeding structures and sexual selection is a common phenomenon in nature. The purpose of this lab was to determine if canine size and bite force is sexually dimorphic in Arctic foxes (Vulpes lagopus). The canine width of female and male fox skulls was measured, as well photographs of fox skulls were used to measure bite force. Data from the class was used to show evidence of arctic fox males to be found to have larger canine width as well as a larger …show more content…
It is the systematic physical differences between individuals of different sex in the same species. Males and Females in most animals have different reproductive organs, and other sexual differences in traits such as their size, colour, odour and shape. Sexual dimorphism is common in very common in nature. The collared lizard and the purple-throated Carib are common sexual dimorphism. The collared lizard (Crotaphytus collaris) is known its enlarged jaws and jaw adductor muscles of male and the female has smaller much smaller jaw and jaw adductor. The distinction between the jaw strength and size is an example of sexual dimorphism as well as intersexual selection as males with larger mouths attract the females. This creates interest in the species to determine the evolution of the collared lizard as sexual dimorphism allows scientist to have the ability to enhance reproductive success and survival. This sexual dimorphism also occurs in many other species such as the purple-throated carib ( Eulampis jugalaris). This is a type of hummingbird that is characterized by the male size, and the beak sizes of the female and male(Gowda,2012). The female’s beak is 20% longer and 30% more curved than the males(Gowda, 2012).Dimorphism is common in feeding structures as they can be important …show more content…
The bite force in the collared lizard was compared to territory size, the mating success, number of females inseminated and the reproductive output in the male lizard. As shown in the experiment, the individual with the greatest bite force performance maintained the largest territory, resulting in an overlap of most of the females, and had resulted in the second highest potential reproductive output. In contrast, lowest bite force individuals had the smallest territory, which overlapped the a smaller amount of females, has accounted for the lowest estimated number of inseminated females, and had the lowest potential reproductive output (Lappin and Husak, 2005). Food competition between males and females can also help explain sexual dimorphism in the Arctic