Each of them typically exists in igneous rock, or rock made from cooled magma.
Fossils, however, form in sedimentary rock -- sediment quickly covers a dinosaur's body, and the sediment and the bones gradually turn into rock.
Also used to describe the process of genetic change within a population, as influenced by natural selection.
adaptive landscape: A graph of the average fitness of a population in relation to the frequencies of genotypes in it.
Since there is no overturning, the rock at the bottom is older than the rock on the top by the Law of Superposition.
The American Heritage Science Dictionary Copyright 2002.
If such a behavior is even partly genetically determined, it will tend to become widespread in the population.
Dinosaur bones, on the other hand, are millions of years old -- some fossils are billions of years old.
To determine the ages of these specimens, scientists need an isotope with a very long half-life.
"Kinetics of amino acid racemization (epimerization) in the dentine of fossil and modern bear teeth".
The mass of water vapour present in the air expressed as a percentage of the mass that would be present in an equal volume of saturated air at the same temperature Compare absolute humidity Collins English Dictionary - Complete Unabridged 2012 Digital Edition William Collins.