the-psoriasis-treatment

As far as explaining natural phenomena, Darwin was one of the best theoretical researchers of all time. Yet, there were a few phenomena that puzzled him for many years. One was the evolution of survival-impairing traits such as the peacock’s train, the large and brightly colored tail appendage observed in males. Tha male peacock’s train is detrimental to the animal’s survival, and yet it is clearly an evolved trait ( ). This type of trait is known as a “costly” trait – a trait that enhances biological fitness (or reproductive success, not to be confused with “gym fitness”), and yet is detrimental to the survival of the individuals who possess it ( ). Many costly traits have evolved in animals because of sexual selection. That is, they have evolved because they are sexy. Costly traits seem like a contradiction in terms, but the mechanisms by which they can evolve become clear when evolution is modeled mathematically ( , ). There is evidence that mental disorders may have evolved as c...

I find costly traits fascinating, even though they pose a serious challenge to the notion that living as we evolved to live is a good thing . It is not that they always deny this notion; sometimes they do not, but add interesting and somewhat odd twists to it. Costly traits have evolved in many species (e.g., the male peacock’s train) because they maximize reproductive success, even though they are survival handicaps. Many of these traits have evolved through nature’s great venture capitalist – sexual selection. (Source: Vangoghart.org) Certain harmful mental disorders in humans, such as schizophrenia and manic–depression, are often seen as puzzles from an evolutionary perspective. The heritability of those mental disorders and their frequency in the population at various levels of severity suggests that they may have been evolved through selection, yet they often significantly decrease the survival prospects of those afflicted by them (Keller & Miller, 2006; Nesse & Williams, ...