Living Fossils

evolution · ancient creatures · biology

Ancient body plans. Living fossils have body shapes that stayed almost the same for millions of years, even though the world changed completely around them. Examples include horseshoe crabs and coelacanth fish, which look nearly identical to their ancestors from hundreds of millions of years ago.

Never truly the same. Even though a living fossil looks like its ancient relative, it is never actually the same species because its DNA slowly changes over time through genetic drift. This means that under the microscope, a modern horseshoe crab is genetically different from its prehistoric ancestor, even if they look almost identical.

Survivors of time. Living fossils usually come from species groups that have very few members today, suggesting they survived in special environments where they didn't need to change much. They are like nature's winners in the game of staying the same for an incredibly long time.

Scientists debate the term. Scientists now avoid using the term 'living fossil' because it can be misleading about how evolution actually works. The term is still popular with regular people because it perfectly describes creatures that seem frozen in time.