What are the sources of pressure that change and influence the development of gaap?

GAAP (generally accepted accounting principles) is a group of commonly observed accounting rules and standards used for financial reporting. GAAP is designed to make sure that financial reporting is clear, and accurate from one organization to another.  

The sources of pressure that change and influence the development of GAAP are numerous, and they include academicians, governmental agencies, private companies, practicing accountants, professional accounting bodies, and public opinion.

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

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primary succession begins with a bare rock and ends with a forest secondary succession begins after a natural disaster where there is a temporary setback after a forest fire or local destruction, but the surrounding area can fill in