Specific conditions must be met for a plant or animal to fossilize. For example, almost no fossil record exists for jellyfish or worms. This is because soft tissues
were rarely preserved, but hard tissues, like bones and shells, fossilized much
more frequently. Also, while fossils can form in a number of ways, most are formed
when a plant or animal dies in a watery environment and is buried in mud and silt.
Plants and water creatures are thus more often fossilized than land creatures.
Which factor likely contributed most to limiting the number of fossils of land
creatures?
Most land creatures were almost entirely made up of softer tissues
that decayed too quickly to fossilize.
2
Plants and water creatures fossilized in the most common way, while
land creatures fossilized in other ways.
3
Most land creatures probably died away from watery environments
where they would be covered in silt.