Africa has vital evolution data

Joel Avni

Joel Avni

The history of life's evolution is written in Earth's rock and scientists today are finding that Africa has one of the most complete records on the planet.

Africa, and South Africa in particular, is already acknowledged as the most complete source of human evolution. This is from a string of related hominids, by way of the apes from which we diverged about 10million years ago.

But that is a minute fraction of the 4billion-year history of life on this strange planet. Unlike the billions of other chunks of rock swirling around in the universe, planet Earth revolves around our nuclear-powered sun in just the right condition to support life.

And by another fortuitous twist of fate, Africa's rocks have survived the rigours of geological calamities better than anywhere else on Earth as continents broke up and then crashed together throughout our planet's almost 15-billion year history.

Scientists recognised the complexities of the process only when Charles Darwin published his theory of evolution in 1859.

His model provided a framework on which to piece together this 4billion-year history of evolution from simple single-celled organisms to complex mammals such as ourselves.

Many of the first records were deciphered from the rocks of Europe and North America, especially for the age of dinosaurs, 300million or so years when these reptiles roamed the Earth.

This is before mammals took their place after a mass extinction 65million years ago.

Only now are scientists recognising that Africa's rocks contain as important a record of this period as is found anywhere on Earth.

Paul Serano, a US palaeontologist, stumbled across his first fossil of an African dinosaur in an expedition through the Sahara.

Ever since then, he has been leading one expedition after another, to uncover the secrets of Africa's distant past and how central a role this continent has played in the history of dinosaurs.

Serano has uncovered a monster 13m ancient crocodile that weighed 8 tons and terrorised the dinosaurs of the Sahara when they came to drink at rivers 110million years ago. Back then the Sahara was a moist environment with wide flood plains, lush vegetation and verdant conifer forests.

He has also discovered a host of carnivorous dinosaurs that preyed on the herds of herbivores that grazed the vegetation of the day. Neither the common flowering plants we know today nor the grasses had evolved then.

The lion of the times was the 11m Suchomimus, a predator that sported a thumb nail large enough to open a modern car like a tin can.

Flying dinosaurs, called pterosaurs, dominated the skies on wings that spanned almost 5m. All around on the plains vast herds of dinosaurs grazed the early plants that then covered the world.

Guess what? Serano has found they were as different from the northern hemisphere plant-eating dinosaurs as modern African antelopes are from the deer that now graze in Europe and America.

Serano and his team are scientists unlike the stereotypical dreary lab-coated fuddy-duddies.