Key evolutionary fossils uncovered

FOSSILS of some of the first life forms to make the pivotal jump from the oceans to land have been found on the edge of a remote Scottish loch.

Rocks around Loch Torridon, on Scotland’s west coast, contain the preserved remains of organisms that once lived at the bottom of lakes a billion years ago.

They mark a key moment in evolution when simple bacteria started to become more complex collections of cells capable of photosynthesis and sexual reproduction.

“These new fossils show that the move toward complex algal cells living in lakes on land had started over a billion years ago, much earlier than had been thought,” said Professor Martin Brasier, from Oxford University’s Department of Earth Sciences.

His research is reported in the journal Nature.

Unlike their bacterial ancestors, the cells had specialised structures including a nucleus, as well as machinery vital for photosynthesis.

They also reproduced sexually, which helped to speed up evolution.

Experts believe the organisms ultimately gave rise to green algae and land plants.

About 500 million years after the appearance of the life forms, the land surface began to be colonised by simple vegetation such as lichens, mosses and liverworts, said the scientists.

At about the same time the first simple animal organisms began to migrate out of the sea.