Carbon 14 dating biology

17-Jan-2018 13:24

Carbon dating looks at the ratio of radioactive carbon, which is naturally present at low levels in the atmosphere and food, to normal carbon within an organism.

While a creature lives, eats and breathes, its ratio of radioactive to normal carbon will equal that of its environment.

In other words, we have a ‘clock’ which starts ticking at the moment something dies.

Materials that originally came from living things, such as wood and natural fibres, can be dated by measuring the amount of carbon-14 they contain.

In fact, the whole method is a giant ‘clock’ which seems to put a very young upper limit on the age of the atmosphere.

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Think of it like a teaspoon of cocoa mixed into a cake dough—after a while, the ‘ratio’ of cocoa to flour particles would be roughly the same no matter which part of the cake you sampled.So detecting the subtle change in the ratio of normal to naturally occurring radioactive carbon over just a few years is incredibly hard.But Jonas Frisén of the Karolinska Institute in Stockholm, Sweden, says it can be done if one takes advantage of the signal left by nuclear testing, which spewed high levels of carbon-14 into the air during the Cold War.By the time a halt was called to aboveground nuclear testing in 1963, levels of carbon-14 in the atmosphere had doubled beyond natural background levels, says Frisén. By taking this into account, one can see detectable changes in levels of carbon-14 in modern DNA, he says.

"Most molecules of the cell will turn over all the time.Carbon-dating Carbon dating, like other radiometric dating methods, requires certain assumptions that cannot be scientifically proved.