Journey of Life - Seas of Life 4
Steve travels back 3.8 billion years to when life began. Journeying round the oceans, he explores life's first laboratory and discovers how the incredible variety of sea creatures arose, from the first microbes to hagfish and dolphins.
"And that is the greatest oxygen breather of them all, the largest animal that’s ever existed- the blue whale."
They can be as long as a 737 passenger jet and weigh as much as thirty bull elephants. Their massive lungs are four hundred times bigger than my own. And when they return to the surface for air, they blow a water spout 12 meters high. Every year migrating blue whales gather here off the coast of California to feed on tiny little shrimp-like creatures called krill. Blue whales have huge appetites. They can take in fifty tons of water in one gulp, and eat forty million krill a day. Here in Californian waters there are more than 2,000 of these giants. This is the greatest gathering of blue whales anywhere in the world.
"But how could evolution take such a gigantic leap? Could a blue whale really evolve from a single cell? With teamwork and cooperation, yes."
Cooperating cells. Sounds a simple solution, but the journey of life took almost 3 billion years to get there. Among the first sea creatures to benefit from cells pulling together were jellyfish.
These ancient animals were the first to have muscle fibers and a simple nervous system, which allowed the first coordinated movement. But unlike us, the jelly doesn't know its front from its back. It just reaches out in all directions.
"With the jellyfish, there was no front end, no brain, and no great sense of direction. The alternative strategy was to grow a head, and with that life could now move forward."
Would you believe this is one of the most important creatures in the whole journey of life, the first ever to grow a head-the flatworm? |
