Applied Biology 19.1

many organisms are completely buried in volcanic ash

fossils do not preserve accurately the once-living animal

most fossils are formed in sedimentary rock

many organisms die without leaving fossils

is easy to recognize

had a wide geographic distribution

lived for a short period of time

is very rare

lived for a long period of time

fossils found in a layer of rock estimated to be between 15,00 & 25,000 years old

fossil estimated to be over 200,000 years old

sedimentary rock with a leaf imprint of undetermined age

an index fossil known to have lived int eh oceans 1 million years ago

equal periods of time

major changes in teh fossil record

historic fossil discoveries

major events in human history

natural selection

plate tectonics

geologic time

continent displacement