Carbon dating age fossil
However, these “molecular clocks” are sometimes inaccurate and provide only approximate timing.
For example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved, and estimates produced by different approaches to this method may vary as well.
If a fossil is found between two layers of rock whose ages are known, the fossil’s age is thought to be between those two known ages.
Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is difficult to match up rock beds that are not directly adjacent.
Carbon-14 is also passed onto the animals that eat those plants.
After death the amount of carbon-14 in the organic specimen decreases very regularly as the molecules decay.
Love-hungry teenagers and archaeologists agree: dating is hard.
This rate is represented by the half-life, which is the time it takes for half of a sample to decay.
For example, if fossils of B date to X million years ago and the calculated “family tree” says A was an ancestor of B, then A must have evolved earlier.
It is also possible to estimate how long ago two living branches of a family tree diverged by assuming that DNA mutations accumulate at a constant rate.
There are several different methods for estimating the ages of fossils, including: Paleontologists rely on stratigraphy to date fossils.
Stratigraphy is the science of understanding the strata, or layers, that form the sedimentary record.