700,000,000 years ago one single act of origination started us downthe road to having vision. That it appears unique is interestingunless there is a reason it is hard. I would prefer easy andmultiple originations and a sorting out.
It is still a long time ago and reminds us of the antiquity of ourcore biological toolkit inheritance.
Everything began as a cellular application with huge variationpossible. Recall that natural selection works wonderfully at thecellular level. It is much more doubtful thereafter. Then theorganism is unconsciously able to modify his offspring and we get anevolution of successful choices instead.
New study shedslight on how and when vision evolved
by Staff Writers
Bristol UK (SPX)Oct 31, 2012
http://www.terradaily.com/reports/New_study_sheds_light_on_how_and_when_vision_evolved_999.html The study, which usedcomputer modelling to provide a detailed picture of how and whenopsins evolved, sheds light on the origin of sight in animals,including humans. The evolutionary origins of vision remain hotlydebated, partly due to inconsistent reports of phylogeneticrelationships among the earliest opsin-possessing animals.
Dr Davide Pisani ofBristol's School of Earth Sciences and colleagues at NUI Maynoothperformed a computational analysis to test every hypothesis of opsinevolution proposed to date.
The analysisincorporated all available genomic information from all relevantanimal lineages, including a newly sequenced group of sponges(Oscarella carmela) and the Cnidarians, a group of animals thought tohave possessed the world's earliest eyes.
Using thisinformation, the researchers developed a timeline with an opsinancestor common to all groups appearing some 700 million years ago.This opsin was considered 'blind' yet underwent key genetic changesover the span of 11 million years that conveyed the ability to detectlight.
Dr Pisani said: "Thegreat relevance of our study is that we traced the earliest originof vision and we found that it originated only once inanimals. This is an astonishing discovery because it implies thatour study uncovered, in consequence, how and when vision evolved inhumans."
Paper: 'Metazoan opsinevolution reveals a simple route to animal vision' by Roberto Fueda,Sinead C. Hamilton, James O. McInerney, and Davide Pisani in PNAS.
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