First eyes EVER SEEN (by definition) appeared 700 million years ago
Here's looking at you, jellyfish
Animals were seeing stuff a lot earlier than previously thought, a new study suggests.
When exactly the ability to see evolved in animals has been hotly contested among boffins, but researchers from Bristol and Maynooth universities reckon a group of marine animals first "saw" the light 700 million years ago.
Using computer modelling, the scientists figured out how and when opsins evolved in a group of marine animals including jellyfish, which are considered to have had the world's earliest eyes. Opsins are the protein receptors which confer the ability to sense light in all animals that have had sight throughout time.
The program used data from every hypothesis of opsin evolution to date as well as all the available genomic information from a recently discovered group of sponges called Oscarella carmela and Cnidarians, or jellyfish.
The team, from Bristol Uni's School of Earth Sciences and National University of Ireland Maynooth, now reckon that an opsin ancestor common to all the group started showing up 700 million years ago. That opsin was 'blind' but over the next 11 million years it evolved genetically to allow it to detect light.
"The great relevance of our study is that we traced the earliest origin of vision and we found that it originated only once in animals," Dr Davide Pisani of Bristol said. "This is an astonishing discovery because it implies that our study uncovered, in consequence, how and when vision evolved in humans."
The study was published in the Proceedings of the National Academy of Sciences (PNAS). ®
Re: But but...
Awww crap I'm gonna bite (wish me luck folks).
Since I've done radiodating of geological samples I might be speaking with a small amount of (slightly hung over) authority, or I could be part of the evil cabal of earth scientists who are hoping to become infinitely rich by telling people the world is really, really, really old (and very cool - apart from the hot bits obviously).
The age of the Earth isn't solely derived from U->Pb dating (although that was the first method tried). The relative volatility of lead is a real problem with older samples which are likely to have been metamorphosed since original crystallisation. Instead the range of dates for the formation of the Earth is based on various dating methods including Pb -> Pb, Sm -> Nd, Rb -> Sr and Re -> Os, all of which come in around 4.51 - 4.68 Gya with a typical range of +/- 0.15Gy.
Pb -> Pb dates are referenced against a geochron which was taken from meteoritic dates of IIRC three stony meteorites of different compositions and two iron meteorites. If you want detail look up the Holmes-Houtermans method for Pb -> Pb dating. Basic chemistry tells us that the iron-nickel troilite alloy of iron meteorites is depleted in uranium so it will not contain radiogenic lead derived from uranium decay. So the ratios of lead isotopes in iron meteorites are those of the primeval solar system.
C-14 in diamonds? If you're talking about the Baumgardner and RATE work, it has been heavily criticised for not following proper procedures in handling carbon isotopes. Anomalous radiocarbon readings are occasionally found in studies of carbonates, but the fact the vast majority of geological samples do not show radiocarbon forces us to conclude that the problem is either with instrumentation or with the way samples are prepared for analysis.
Ocean salinity? Really? Seriously? You're still using that one. Look Edmond Halley didn't know how evaporite deposits form or how widespread they are. T. Mellard Reade, John Joly and George Becker didn't know about plate tectonics - they didn't know that ocean waters (containing salt) are in intimate contact with magma at mid-ocean ridges; that a volume of water equivalent to the entire ocean passes through the oceanic crust every 10 million years; or that salt water is subducted into the Mantle in ocean plates and sediments.
In short, a lot of science has happened.
This discovery probably means that the date of the first porn needs to be updated as well.
Re: But but...
The scientists "guesses" get promoted when they become useful tools to describe and predict things. If those guesses are unsuccessful at describing and predicting, they get thrown out or overthrown by "guesses" that do a better job. That is the scientific method. Why does it scare people?
Kids wouldn't have bias, but kids also would not have enough information and context to accurately weigh the position of each side of the argument.
Still, are you suggesting that we present two options to otherwise uninformed kids:
1 - over billions of years, ruled by these forces between particles and energies, we have all this.
2 - A few thousand years ago, some untestable omnipotent thing got bored and Poofed everything into existence, including elaborate fossil histories. Just trust us. Don't question it. Want some candy?
Did you ever see your great great great grandparents? If not, do you therefore think that they did not exist?
Why are so many people afraid or unable to think?