We all understand the twings of discomfort
at the thought that we share a common ancestor
with the apes.
No one can embarrass you, like a relative.
Our closest one, the chimpazees frequently
behave inappropriately in public.
Theres an understandable human need to distance
our selves from them.
The central premise of traditional belief
Is that we are created seperately from all
the other animals.
It's easy to see why this idea has taken hold,
it makes us feel... special.
But what about our kinship with the trees?
How does that make you feel?
Okay, heres a segment of the oak tree's DNA.
Think of it like a barcode, the instructions
written in the code of life, tell the tree
how to metabolize sugar.
Now lets compare it with the same section
of my own DNA.
The DNA doesn't lie, this tree and me... are
long lost cousins.
It is not just the trees, if you go back far
enough you will find, we share a common ancester
with: the butterfly, the grey wolf, mushroom,
shark, bacterium, sparrow, what a family!
Other parts of the barcode differ from specie
to specie, thats what makes the difference
between an owl and an octupus.
Unless you have an identical twin, there's
no one else in the universe with the exact
same DNA as you.
Within outher species, the genetic differences
provide the raw material for natural selection
the environment selects which genes survive
and multiply.
When it comes to the genetic instructions
for life's most basic functions, say, digesting
sugar we and other species are almost identical.
Thats because those functions are so basic
to life, they evolved before the various lifeforms
branched off from the tree.
This is the Tree of Life, science has made
it possible for us to construct this family
tree for all the species of life on Earth.
