No Island Fossils

The lack of transitional fossils

Evolutionary theory spent much of its early years embarassed about the lack of transitional forms in the fossil record.

This page presents a theory that helps explain why such fossils are rare.


Islands are important as crucibles for new species, and it seems reasonable to expect that much of the world's gradual evolution has taken place on them.

No Island Fossils

However islands leave relatively few fossils.

Many islands are volcanic - and fossils tend to prefer to take up residence in sedimentary rocks.

Many other islands are eventually eroded and crumble into the sea. This must be an extremely common fate of small islands. Such an island will leave no fossils.

Next, fossils tend to form in sediments in lakes. Islands are less likely to have lakes in the first place. Many lakes are high in the mountains - where the ground is rocky. Islands tend to form from more coastal land. Islands have large perimeters, and it is easy for the perimeter to intersect what was once a lake - and thus drain it. Even for lakes inland, the small scale of an island may reduce its drainage basin - and fewer animals will leave bones in smaller lakes.

These facts may help explain the relatively low frequency of transitional forms in the fossil record.

Tim Tyler | Contact |