Information

Living fossils


Coelacanth, anteater, gingko ...

A living fossil is understood to mean recent species that have already lived in similar form in another period of Earth history. The term "living fossil" in itself is misleading because the term assumes that living fossils have not undergone evolutionary development since their emergence. However, this is not the case since evolutionary factors have also permanently affected living fossils. In contrast to other species, however, the morphology has changed only slightly, to hardly any.
At first glance, living fossils are more of a proof that evolution is not happening. This particular form of species groups is explained by the existence of extremely stable ecological niches that provide for constant environmental conditions (such as in the deep sea), so that species remained virtually unchanged over millions of years, since adaptation was not necessary from the point of view of stabilizing selection.

The coelacanth

The first found fossilized coelacanths date back to about 400 million years to the Devonian Era. Until its rediscovery in the late 40 'years, the coelacanth was even considered extinct. The particularity of living fossils is often that they combine characteristics of two different groups. In the case of the coelacanth, in addition to the typical characteristics of fish in the form of scales and gills, the presence of amphibious features, e.g. Walked over and a lung. This fact makes the coelacanth a bridgehead and thus provides evidence for the evolutionary change of species, so that it can be assumed that species have not developed side by side, but apart.
The following cladogram shows the evolution of the different groups (terrestrial vertebrates):
If they had developed side by side, there would be no nodes, so no organisms would have the characteristics of two groups. But the existence of such bridge animals as the coelacanth (fish and amphibian), anteater (reptile and mammal) but also the archaeopterix (reptile and bird) prove an evolutionary evolution from the previous species.