Plant Evolution – Algae to Angiosperms
Excerpt 1 from the book Science for the gardener to be published 2017
It all started with a bang – a very big bang – nearly 14 billion years ago, or so we are told.
9 billion years later, a mere 4.6 billion years ago, planet earth an immensely hot magma blob was created, steamy and foul smelling, a mixture of dust and gasses.
Evolution had begun – a time line of such gigantic proportions the figures are almost impossible for us to comprehend. To think that we, the human race, and everything we see and know around us on our planet earth evolved from a smelly mixture of dust and gasses.
First things first, the earth needed to cool down. It took another billion or so years for this to happen and a crust to form around the earth (rather like the skin on custard).
The figures are mind boggling I know, but bear with me things do get more interesting.
As the outer layer began to cool a little, volcanoes began to appear from the depths of the still very hot planet. Volcanoes produce water vapour, lots of it, from hydrogen and oxygen. And, surprise, surprise, that made water. Good old H2O the one scientific formula we all know. Water; we cannot have living matter without water.
The atmosphere at that time was full of very ‘pongy’ and noxious volcanic gases made from the elements of carbon, hydrogen, nitrogen and oxygen. I am sure you are all familiar with some of these gasses such as methane CH4, (smelly) and ammonia NH3 (even more smelly).
These gasses combined with the water vapour produced by the volcanoes and became what we call a primordial soup (don’t suppose it tasted very good!). Just as well we humans were not around at the time; we wouldn’t have been able to breathe because there was no available oxygen. It was all stuck in the soup.
NEXT EDITORIAL CONTINUES WITH PLANT EVOLUTION