Vertebrate Evolution of Color Vision
Vertebrate animals were primitively tetrachromatic. They possessed four types of cones—long, mid, short wavelength cones, and ultraviolet sensitive cones. Today, fish, reptiles and birds are all tetrachromatic. Placental mammals lost both the mid and short wavelength cones. Thus, most mammals do not have complex color vision—they are dichromatic but they are sensitive to ultraviolet light, though they cannot see its colors. Human trichromatic color vision is a recent evolutionary novelty that first evolved in the common ancestor of the Old World Primates. Our trichromatic color vision evolved by duplication of the long wavelength sensitive opsin, found on the X chromosome. One of these copies evolved to be sensitive to green light and constitutes our mid wavelength opsin. At the same time, our short wavelength opsin evolved from the ultraviolet opsin of our vertebrate and mammalian ancestors.
Human red-green color blindness occurs because the two copies of the red and green opsin genes remain in close proximity on the X chromosome. Because of frequent recombination during meiosis, these gene pairs can get easily rearranged, creating versions of the genes that do not have distinct spectral sensitivities.
Other articles related to "evolution":
... to For 1997 Marie-Charlotte Anstett Facilitation and constraints in the evolution of mutualism 1999 Nicolas Galtier Non stationary models of nucleotide substitution and the evolution of base ...
... the investigation, the crew finds evidence of a form of quasi-life, born through evolution of autonomous, self-replicating machines, apparently left behind by an ... The evolution was controlled by "robot wars", and the only form that survived were swarms of minuscule, insect-like micromachines ... it is an imaginary experiment to demonstrate that evolution may not necessarily lead to dominance by intellectually superior life forms ...
... Social effect of evolutionary theory and Objections to evolution In the 19th century, particularly after the publication of On the Origin of Species in 1859, the idea ... However, evolution remains a contentious concept for some theists ... While various religions and denominations have reconciled their beliefs with evolution through concepts such as theistic evolution, there are creationists who believe that evolution is contradicted by the ...
... In 2005, Wells participated in the Kansas evolution hearings, which were boycotted by mainstream scientists ... There Wells testified Prior to the evolution hearings, in December 2000 after the Pratt County, Kansas school board revised its tenth-grade biology ... creationists as revealing some fatal flaw in the theory of evolution ...
... of Coral Ridge Ministries, Johnson gave a speech called How the Evolution Debate Can Be Won ... for winning the battle "To talk of a purposeful or guided evolution is not to talk about evolution at all ... understand it that way, you realize that the Darwinian theory of evolution contradicts not just the Book of Genesis, but every word in the Bible from beginning to end ...
Famous quotes containing the words vision, color and/or evolution:
“Ive been cursed for delving into the mysteries of life. Perhaps death is sacred, and Ive profaned it. Oh, what a wonderful vision it was. I dreamed of being the first to give to the world the secret that God is so jealous of, the formula for life. Think of the power, to create a man. And I did, I did it, I created a man. And who knows, in time I could have trained him to do my will. I could have bred a race, I might even have found the secret of eternal life.”
—William Hurlbut (1883?)
“But whenever the roof came white
The head in the dark below
Was a shade less the color of night,
A shade more the color of snow.”
—Robert Frost (18741963)
“The evolution of humans can not only be seen as the grand total of their wars, it is also defined by the evolution of the human mind and the development of the human consciousness.”
—Friedrich Dürrenmatt (19211990)