Size Matters
Giant Eucalyptus Trees
Size Matters?
Giant Eucalyptus Trees
Our world is covered in Giants. The largest things that ever lived on this planet weren't the dinosaurs. They are not even blue whales. They're trees.
These are Mountain Ash - Eucalyptus, the largest flowering plant in the world. They grow about a metre a year and these trees are 60, 70, even 80
metres high. But to get this big, you need to face some very significant physical challenges.
These giants can live to well over 300 years old. But they don't keep growing for ever. There are limits to how big each tree can get. As with all
living things, the structure, form and function of these trees has been shaped by the process of evolution through natural selection. But evolution doesn't
have a free hand. It is constrained by the universal laws of physics.
Each tree has to support its mass against the downward force of Earth's gravity. At the same time, the trees rely on the strength of the interactions
between molecules to raise a column of water from the ground up to the leaves in the canopy.
Professor Brian Cox
Kangaroo
And it's these fundamental properties of nature that act together to limit the maximum height of a tree, which theoretically lies somewhere in the
region of 130 metres.
With its forests and mountains… Oceans and deserts… I've come to Australia to explore the scale of life's sizes. I want to see how the laws of physics
govern the lives of all living things. From the very biggest… to the very smallest.
The size of life on Earth spans from the tallest tree, over 100 metres tall and with a mass of over 1000 tonnes, to the smallest bacterium cell,
with the length less than 1 millionth of a millimetre and a mass less than a million millionths of a gram. And that spans over 22 orders of
magnitude in mass.
I want to see how size influences the natural world. How do the physical forces of nature dictate the lives of the big and the small? Do organism's
face different challenges at different scales? And do all experience the world differently, based on our size?
The size you are profoundly influences the way that you live your life. It selects from the properties of the natural world that most affect you.
So, I suppose that whilst we all live on the same planet, we occupy different worlds.
