how do scientists use fossils to determine environmental change?

[j_sun]

for my science homework i have to describe two ways that scientists use fossils to determine environmental change? help, please! thanks!

[hummingbird]

continental drift (look it up) same fossils in south America and Africa

[ricki]

if in one plot of land you find sea life (clams, fish, sponges etc) and deeper in that same plot you find semi aquatic life (things like otters, seals, crocs, etc) and in deeper still layers you find fully terrestrial life (deer, bears, etc) you can safely say that the area was formerly terrestrial and changed into a semi- and then fully-aquatic environment

[Melanie]

1.  I was going to go with "the width of tree rings reflects the amount of water available during growing times, and also the ratio of 'cold' to 'warm', and this can be seen in both living trees and in petrified trees."

2.  Looking at layered strata from a fossil seabed, you may be able to see gradual changes, over time, of animals typical of cool water to animals typical of warmer water, and vice versa.