Biology: fossil changes?

Question

The fossil record extends over millions of years. Looking at the different fossils found over time, what sorts of changes occur?

Answer 1

Evolution and extinction.....the fossil record lets you see how the ecosystems of an area are changing over time.....this includes how organisms evolve and also when they go extinct.

When looking at a fossil bed the older layers are obviously on the bottom.  By tracing one lineage throughout you can see how it evolved over millions of years.  Also once that lineage is found in one layer and not in the next you can conclude that it went extinct at that time.  By dating the rock layers that the organisms are found in you can recreate entire ecosystems and really understand what our planet was like before humans came around.  

Another amainzing thing that you can see is a mass extinction event where there would be a lot of organisms in one layer and none in the next which means somehting huge like a metorite impact had to occur.....

Answer 2

Size and adaptability change, usually to fill a food gathering niche.