Half-life is defined as the time it takes for one half of a radioactive element to decay into a daughter isotope.
As radioactive isotopes of elements decay, they lose their radio activity and become a brand new element known as a daughter isotope.
Different isotopes have different half-lives and sometimes more than one present isotope can be used to get an even more specific age of a fossil.
There are two main methods determining a fossils age, relative dating and absolute dating.
The fossil record may be incomplete and may never fully completed, but there are still many clues to evolution and how it happens within the fossil record.
One way that helps scientists place fossils into the correct era on the Geologic Time Scale is by using radiometric dating.
Can yield environmental evidence as far back as 3mya`Based on observation that the annual growth rings of a few tree species vary in width according to differences in seasonal growing conditions (esp. Successful means of calibrating or correcting radiocarbon dates2.
Perhaps the most widely used evidence for the Theory of Evolution through Natural Selection is the fossil record.
Geologic research and mapping requires the determinations of the ages and composition of rocks.
Also called absolute dating, scientists use the decay of radioactive elements within the fossils or the rocks around the fossils to determine the age of the organism that was preserved.
This technique relies on the property of half-life.
Reliability of age = reliability of technique Two artifacts are buried at the same time within the same archaeo.
deposit and can be no alter (no more recent) than the deposit itself Allows to date a field site by dating an artifact because of association Nitrogen, fluorine, uranium, collagen content, gradually reduced by process of chemical decay. Very variable, depends on site's chemical content as well.