When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to nitrogen 14 changes the ratio of carbon 12 to carbon 14.
Experts can compare the ratio of carbon 12 to carbon 14 in dead material to the ratio when the organism was alive to estimate the date of its death.
We thank you in advance for partnering with us in this small but significant way. All methods of radioactive dating rely on three assumptions that may not necessarily be true: It is assumed that the rate of decay has remained constant over time.
This assumption is backed by numerous scientific studies and is relatively sound.
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. 1979, 1986 © Harper Collins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cite This Source (rā'dē-ō-mět'rĭk) A method for determining the age of an object based on the concentration of a particular radioactive isotope contained within it.
For inorganic materials, such as rocks containing the radioactive isotope rubidium, the amount of the isotope in the object is compared to the amount of the isotope's decay products (in this case strontium).
Please remember that all dating methods, even those termed "absolute," are subject to margins of error. That is a very small amount of possible error range. Modern studies almost always use two or more methods to confirm dating work and to build confidence in the results obtained.
Dating is not necessary to demonstrate that evolution is a fact.
Chronological sequence is all that is really required.
The field relationships, as they are called, are of primary importance and all radiometric dates are evaluated against them.
For example, a geologist may examine a cutting where the rocks appear as shown in Figure 1.