What do the ginkgo (a tree), the nautilus (a mollusc) and the coelacanth (a fish) all have in common?
They don’t look alike, and they aren’t biologically related, but part of their evolutionary history bears a striking resemblance: these organisms are referred to as “living fossils”. In other words, they appear to have escaped the transformations that normally come about over time, through evolution.
For the past 85 years, the coelacanth has been dubbed a “living fossil” because it evokes a bygone era, the age of dinosaurs. These fish belong to the sarcopterygians, a group that also includes lungfish (fish with lungs) and tetrapods, a group to which humans also belong. Tetrapods are vertebrates (animals with a backbone) that share specific anatomical features, including the presence of a humerus (forelimb bones), a femur (hindlimb bones) and lungs.
