Radiocarbon dating of fossils
As these changes have occurred, organisms have evolved, and remnants of some have been preserved as fossils.A fossil can be studied to determine what kind of organism it represents, how the organism lived, and how it was preserved.When isotopes are to be designated specifically, the chemical symbol is expanded to identify the mass (for example, C is not stable.As a result it is always undergoing natural radioactive decay while the abundances of the other isotopes are unchanged.Carbon-14 is most abundant in atmospheric carbon dioxide because it is constantly being produced by collisions between nitrogen atoms and cosmic rays at the upper limits of the atmosphere.Despite seeming like a relatively stable place, the Earth's surface has changed dramatically over the past 4.6 billion years.Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.
The period of time that it takes for half of a sample to decay is called a "half-life." Radiocarbon oxidizes (that is, it combines with oxygen) and enters the biosphere through natural processes like breathing and eating.Darwin and his contemporaries could never have imagined the improvements in resolution of stratigraphy that have come since 1859, nor guessed what fossils were to be found in the southern continents, nor predicted the huge increase in the number of amateur and professional paleontologists worldwide. Along with hydrogen, nitrogen, oxygen, phosphorus, and sulfur, carbon is a building block of biochemical molecules ranging from fats, proteins, and carbohydrates to active substances such as hormones.These skeptics do not provide scientific evidence for their views.
Current understanding of the history of life is probably close to the truth because it is based on repeated and careful testing and consideration of data.
The rejection of the validity of fossils and of dating by religious fundamentalists creates a problem for them: Fossil sequences were recognized and established in their broad outlines long before Charles Darwin had even thought of evolution.