Journey of Life - Seas of Life 2
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 where did it all begin? In the sea --home to the most extraordinary variety of creatures. And I'm going to meet them. ("Blue whales! Flying fish! Huh ha ha")The bizarre and the brainy ("you're beautiful...") and the downright scary. ("Ok, fellows, you'll get your chance to bite")
It's time to start my journey and explore the living seas.
The sea is life's laboratory where many solutions to the challenges of living were first developed and tested. It might be hard to believe, but every living thing today can trace its ancestry back to the sea.
"And that includes us humans. For this journey is also a personal story as many of our own features first evolved down here. Even today our own heads and bodies hint at our aquatic origins."
This is you or me, just 24 days after conception. Every one of us was bathed in a warm, salty sea of amniotic fluid inside our mother's womb. Here on the embryo's head are gill slits called pharyngeal pouches. Fish embryos have them too. In fish they do turn into gills. But in humans they become parts of the face, ear and jaw. This long tail is another echo of our evolutionary past. We humans are a tiny shoot on one branch of a giant family tree- the tree of life. We're just one of tens of millions of living tips, each representing different species. And the way they all connect reveals how each and every life form is related. But why did this dazzling diversity start in the sea and not on the land? Let’s travel back to life's very beginning--3.8 billion years ago.
Back then, planet Earth was an unpleasant place. |
