Professor Bruce Rubidge, a man who often thinks about time in terms of eons rather than 24-hour news cycles, has a problem: He needs to discuss the 4.6- billion-year history of the origins of earth and life – and he has to do it over lunch.
"Yes, I have 25 minutes over the break," he says, laughing about preparing for his luncheon talk at the upcoming AAPG International Conference and Exhibition in Cape Town, South Africa.
His talk is called “The Four-Billion-Year Existence of Life – Africa’s Role in Understanding This Remarkable Story,” and Rubidge says he already can feel your eyes glazing over.
"One cannot get too serious in a time like this – people will want something light-hearted and fun."
Obviously, he'll have to skim over a few billion years or so – but that shouldn’t be a problem for Rubidge, who is with the Bernard Price Institute for Palaeontological Research at the University of the Witwatersrand in Johannesburg, South Africa.
"I will try to present a very brief and interesting overview, do the history of life from a Southern African perspective, look at some of the exciting new fossil discoveries from Africa, and concentrate on important evolutionary and biodiversity issues in the ongoing development of life,” he said.
Rubidge, who along with Terence McCarthy, professor of mineral geochemistry at Witwatersrand, co-wrote The Story of Earth and Life, a Southern African Perspective on a 4.6-Billion-Year Journey, believes that one cannot fully understand the earth's pedigree without first understanding the contribution of Africa's role, generally, and South Africa's role, specifically.
"From our very ancient fossil record it is well known that Africa is the place of origin of humans,” Rubidge says, “and much of this story of human origins is based on three-million-year-old or younger fossils discovered in South Africa by noted paleontologists such as Robert Broom, Raymond Dart, Phillip Tobias and Bob Brain."
The Perfect Setting
But Rubidge says that's just one aspect of the story.
"While the human story is one which tends to make the headlines, it is only a very small part of the development of life on earth,” he said. “Because South Africa has a geological history that extends back 3,600 million years, and has younger rocks of all different ages that bear fossils, it is an ideal country to study the development of life.
“In particular,” he added, “the rocks of the Karoo Supergroup, which cover more than two thirds of the total surface area of South Africa, preserve a remarkable history of the origin and diversification of various reptile groups (including mammals, dinosaurs and turtles) from 180-300 million years ago."
More fascinating to Rubidge is that South Africa is " ... the only single country which records such an extended history of ‘reptile’ diversification." Specifically, he notes how the Karoo Region is noted for its rich record of therapsids, the most distant ancestors of mammals, and ultimately, humans.
"South Africa has the most primitive therapsids – and then through the Karoo succession there are progressively more advanced forms – with mammals in the youngest rocks on top,” he said. “By traveling through the Karoo and viewing its fossils one can thus trace the ancestry of mammals."
A Love For Rocks
Rubidge grew up on a farm in the town of Graaff-Reinet, which is situated in the Karoo. He credits much of his enthusiasm and passion for this study to his grandfather.
"My grandfather (Sidney Rubidge), who was a keen observer of nature, developed a great interest in fossils that resulted in him amassing a large collection of fossil 'reptiles' collected from the rocks in the vicinity of his farm during the 1930s," he said.
His grandfather developed “a profitable working relationship with Dr. Robert Broom, then the renowned palaeontologist from South Africa,” Rubidge said, “whereby Grandpa collected fossils and Dr. Broom did the scientific descriptions."
This was pioneering stuff, Rubidge said, and the findings resulted in many of the fossils being described as type specimens (the first specimens discovered of a new species). As a result, the collection – comprising over 800 fossil skulls, containing 118 type specimens – became a very important scientific collection.
Just as important to Rubidge is that his grandfather did this work as a hobby – and on weekends.
If only The Story of Earth and Life could have been completed in his spare time.
"Putting together this book was great fun, but it was also quite a challenge,” he said, adding that “geology, evolution and the progression of life are complex subjects and are not always easy to present to a general audience."
As a result, he says, they asked numerous people to read drafts of the book, including scientists, laymen, children and wives.
Calling his co-author, McCarthy, "the most versatile and knowledgeable geologist I know, who always seems to know everything," Rubidge says the book was written for a simple reason: the two simply love rocks.
"He and I shared a passion to write a story on the remarkably diverse South African rock and fossil record which would have appeal to a general readership."
Saying that while bookstores in South Africa had offerings on insects, birds, reptiles and plants, "there was nothing on geology.
“We set out to write a book that people could take in their car on journeys around the country, which they could read at night while in bed, but which would also be useful for university undergraduate earth and life-science courses."
And apparently for anyone with a few minutes to spare during lunch.