5.) Link between evolution of exaggerated traits and mate selection Jun ha, Zaina, Ruman Evolutionary success Passing of genes to future generations Natural selection Has led to evolution of differences between males and females ‘sexual dimorphism’ Sexual dimorphism = the change in phenotypic differences between males and females of the same species (males and females are physically different in ways other than their sexual organs) Plays a role in indicating which is a stronger mate Darwin found that species where males and females that were similar were more likely to be monogamous Polygamous species have differences to allow males to mate with more females Differences are indicative of stronger characteristics Secondary Sexual Characteristic •Traits that appear to be peculiar to one sex but are not part of the reproductive organs •When you consider peacocks, they have special extravagant traits that can act as an advantage when mating •Through modification, traits can become attractive overtime as seen in peacock feathers. The peacock flares out his feathers when he is trying to get the peahen's attention for the purpose of mating to continue reproducing as means for survival. In some peacocks, males show exaggerated traits. Colourful tail feathers Advertises their reproductive worth to peahens Downsides Tail feathers are an encumbrance Hinders rapid movement, e.g. during attacks by predators Evidence Studies have shown Peahens prefer to reproduce with more colourful peacocks Colourful peacocks are often the strongest, healthiest and least-parasitised males Counterclaim But some research has shown No link between the colourfulness and parasitism Peahens select males with the loudest vocalisation Thus peacock’s colour may not indicate health Runaway evolution Colourful peacock feathers may be an example of Runaway evolution There are other examples like... The lyre bird is able to imitate sounds of at least 20 different species to scare their rivals (males) When male deer fight with their strong antlers to show superiority Singing (sense: sound) of Blackbirds Reverse dimorphism = when females develop the dominant traits Blue whales- females are larger as they’re easier to find Black myotis- females are larger to facilitate egg formation (which need more energy) Sources Antigrandiose. File:Peacock Milwaukee County Zoo.jpg. Digital image.En.wikipedia.org/. 24 June 2010. Wikipedia. 20 Feb. 2012 <http://en.wikipedia.org/wiki/File:Peacock_Milwaukee_County_Zoo.jpg>. Boultont. "Explain how mate selection can lead to exaggerated traits."Ibbiology.wetpaint.com. 29 May 2009. Wetpaint. 20 Feb. 2012 <http://ibbiology.wetpaint.com/page/Explain+how+mate+selection+can+lead+t o+exaggerated+traits>. Pape, Dave. File:Golden tiger 1 - Buffalo Zoo.jpg. Digital image. En.wikipedia.org/. 16 Dec. 2006. Wikipedia. 20 Feb. 2012 <http://en.wikipedia.org/wiki/File:Golden_tiger_1_-_Buffalo_Zoo.jpg>. http://animal-unique.blogspot.com/2011/10/blue-whale.html http://en.wikipedia.org/wiki/Sexual_dimorphism http://animals.about.com/od/zoology12/f/sexualdimorphis.htm