Plants take in atmospheric carbon dioxide by photosynthesis, and are ingested by animals.
So, every living thing is constantly exchanging carbon-14 with its environment as long as it lives. The carbon in its body will remain until it decomposes or fossilizes.
In the following article, some of the most common misunderstandings regarding radiocarbon dating are addressed, and corrective, up-to-date scientific creationist thought is provided where appropriate. Radiocarbon is used to date the age of rocks, which enables scientists to date the age of the earth.
Radiocarbon is not used to date the age of rocks or to determine the age of the earth.
So, using carbon dating for fossils older than 60,000 years is unreliable.
Carbon dating was developed by American scientist Willard Libby and his team at the University of Chicago.
The field of radiocarbon dating has become a technical one far removed from the naive simplicity which characterized its initial introduction by Libby in the late 1940's.