The beginning of the human race was caused by changes in the currents in the ocean, audiences at Bermuda Underwater Exploration (BUEI) will hear tonight and tomorrow.

Renowned science author Deborah Cramer will cite the evolution of human beings as one example of how the oceans are life-giving entities that need to be protected. She has just published to rave reviews Great Waters: An Atlantic Passage, which is based on a three and a half week journey from Woods Hole Oceanographic Institute in Massachusetts to Barbados.

Ms Cramer explained yesterday how the joining together of North and South America when the Isthmus of Panama rose from the sea cut off the free flow of water between the Atlantic and the Pacific.

But warm winds blew over, heating up the water which blew northward in the Gulf Stream. When this water reached Labrador and the Greenland Sea, it released moisture which caused snow, and started the Ice Ages. As the ice descended from the poles, Ms Cramer explained, Africa cooled and woods disappeared giving way to grass, forcing an ape species known as Australopithecus, which had been untouched by evolution for one and a half million years, to come down from the trees and walk.

Their babies, who did not need their limbs to climb, grew their brains at an unprecedented rate. In her book, which she says calls on a number of respected scientific publications, Ms Cramer notes that the slow moving Australopithecus fell prey to swift meat eaters, while the newly evolved Homo, used its larger brain to survive.

“Within a split second of geologic time, in little more than 100,000 years, Australopithecus died out. Homo survived, filling a niche created by a change wrought by the sea. The sea brought us here,” she wrote.

She told The Royal Gazette: “I will be talking about what the sea has given us because most people don't really understand it. The waters are truly life-givers and this (the birth of humankind) is an example of it.

“If you think of the sea, it is very big and all the waters are connected together. If people could understand what we have been given, they wouldn't tolerate what we are doing.

“Most people don't really understand what we are doing, and if they do understand, they don't know why it matters. Global warming is going to alter the flow of the Gulf Stream and change the patterns of currents.

“There will be a restructuring of the food webs in the ocean and that is dangerous because we eat fish. Most people think we get oxygen from trees, but we get 40 percent of our oxygen from invisible plants in the ocean.”

Tickets for Ms Cramer's talk, which begins at 7 p.m., are still available from BUEI.