This means that females will be producing sons and daughters with both choice and exagerated trait genes together. Because the exagerated males have an advantage, Female Choice and the male trait spread, and they spread together linked by assortative mating, almost like a wild fire, or as Fisher termed a Runaway Process . Basalo looked a genus of Sword-tailed fish, Xiphoporus, which have elongate swords. Basalo asked whether females from this ancestral species preferred males of their own species which lack a sword, or males of their own species with swords tied on. Alternative Male Strategies Males do not just have to be big and aggressive to gain access to females.
Many Organisms display two of the three types described above.
An unusual game is being played out in the Coast Range of California. Each strategy in this game has a strength and a weakness, and there is the evolutionary rub that keeps the wheels spinning. In ESS models you consider how well a male type does when it is rare compared to when it is common. In this model, the fitness of a male type when rare is different compared to when it is common. This is described by the Pay-Off matrix which describes the fitness of each male type when rare, competing against each other type when common.