For some, life is like a beautiful, endless symphony.
For others, it's more like the music
of an inebriated street busker just moments before he's arrested -
nasty, brutal and short.
Well, I'm here to tell you that it's actually both,
and through a series of fundamental biological questions, such as...
How am I related to a mouse?
War, what is it good for?
And am I hot or not?
Just some of the things you need to know about evolution.
We'll begin with biology's grand maestro - Charles Darwin.
And what's always bothered me is this.
Unless you live under a rock,
you'll have heard of Charles Darwin.
But before developing his revolutionary theory of evolution,
Darwin's life was somewhat non-biological.
First, he quit medical school
because it was always making him sick.
And then he very nearly entered the priesthood.
CHEERING
So, given that he was on course to become a servant of God,
it's perhaps not surprising that Darwin wasn't the first person
to suggest the notion of evolution.
The idea that evolution has occurred was not new.
Er, for example, Charles Darwin's own grandfather,
he had written about that evolution has occurred, organisms have changed,
and he talks about millions of ages, means the world is very old.
Carolus Linnaeus, a Swedish botanist,
in 1735 put humans and apes into the same group,
sort of into an organised taxonomy.
The person that's probably most important is Charles Lyell,
because Lyell was a geologist and he was interested in how
the surface of the earth changes and the fact that it's not static
but that mountains sort of arise and lakes and rivers move around
and the idea that these are very gradual slow changes
over a long period of time.
I think Darwin was really influenced by that, because he figured,
you know, this could be applied to organisms too.
Darwin really got into naturism...
sorry, I mean naturalism, at university,
but had to find his sea legs to make a career of it.
that rocked Darwin's world.
It began with Galapagos finches,
whose beaks all looked different across the island chain.
Each beak seemed to have adapted to whatever food was on offer,
be it seed, cactus,
or grub. Ugh.
Darwin saw this as no coincidence,
and began to investigate other adaptations.
His study took another 20 years to complete.
But his conclusions went against everything
the prevailing God-based theory said about life's origins.
Darwin's take was that useful adaptations existed in all living species
and were inherited through a process he called natural selection,
and that nature alone was the driving force
behind millions of years of evolutionary change.
With that, Darwin became the daddy of modern biology.
Not bad for a squeamish wannabe priest.
Uggghh!
Darwin's theory is now considered to be fact by most serious scientists.
But even he couldn't really explain how these adaptations came about.
These days, however, we know
that they are the work of ugly, hideous little things
that are normally the preserve of science fiction,
ie, mutations.
But this begs a rather difficult question.
Are we all mutants?
Think mutant, and you might think Godzilla.
But evolution's mutants are minute compared with him.
Our story begins in the 1850s,
when the Austrian monk Gregor Mendel discovered
how genetic traits were inherited, by breeding giant peas.
But this only scratched the surface.
He was breeding giant peas and dwarf peas
and instead of the offspring being sort of a blend of the parents,
they turned out to either be identical to the one parent
or the other parent.
But he didn't quite understand how it worked, the mechanism behind it,
because he didn't really know about things at the molecular level,
what was happening inside organisms, inside cells.
Then, in the 20th century, we discovered the hideous truth.
Molecular mutation.
Not caused by experimentation,
but microscopic errors in the genetic code
hidden within each species.
Mutations are entirely random events, and most of the time
they're agents of evil.
But occasionally they're forces for good, offering mini upgrades
like better vision,
faster flight, or, in the case of this monster, more bite.
Meet obtusacanthus, an extinct 400-million-year-old fish,
with a freaky face.
In 2011, scientists found teeth outside its mouth.
The theory is that the first teeth started out as fish scales
that randomly mutated.
But the randomness ends with natural selection or death.
If the mutation offers any kind of edge,
it gets passed on to the next generation.
Those without the mutation, well...
And, while mutations are random events,
the process of evolution through natural selection isn't,
because it's the ones with the beneficial mutations
that go on to survive and then reproduce.
Obtusacanthus' freaky face helped to hook its lunch.
But it took millions of years for teeth to become a total mouthful,
as seen in all the toothy mutants alive today.
And, yes, that includes you.
Let's just think about that for a second.
If we are all simply mutations of earlier species,
then we must all be connected -
humans, dogs,
cats, mice.
So, how am I related to a mouse?
At least 95% of the recipe book for Homo sapiens, that's you,
is the same for chimpanzee.
With mice, the figure is about 85%.
And cabbage, roughly 40%.
That doesn't mean we're 40% cabbage -
nobody could stomach that much green.
It means that some of the genetic instructions used during the cooking process
are shared across species of both meat and veg.
I laugh when I read in the newspaper
and somebody says, you know, "Mr Smith, no relation to Bob Smith,"
and I always say, "Of course we're related.
"I'm related to a mouse, I'm related to a bacterium." We're all related.
We may have different genes and different sequences,
but the basic biochemical machinery hasn't changed.
What has changed is how we make the body.
You can see that a group of different species might be closely related
because they share 90% of the genes with each other.
And so that would suggest that they've diverged from each other relatively recently.
This information can be found in a vital chapter
of the evolutionary cookbook.
It's called Common Ancestry.
The living world is like a very large 3.8-billion-year-old tree,
with today's organisms at the top.
Go back in time, and you'd see where each species branches off.
The earliest known human recipe is possibly Homo gautengensis,
which is about two million years old.
There's evidence that those guys may actually have used fire,
which would make them amongst the world's first chefs.
Go back 160 million years
and you'll find the recipe for Juramaia sinensis.
Found in China in 2011,
it's believed to be the oldest common ancestor of mice and humans,
because they're the first known placental mammals,
that gave birth to live young.
We're not really sure what the first ever recipe consisted of,
but we've named it LUCA.
The Last Universal Common Ancestor.
But I wouldn't try it if I were you - it's 3.8 billion years old.
Bleeeuurgh!
Of course, when we talk about things that are millions of years old,
we are talking primarily about fossils.
And it is, unfortunately, quite difficult to get them to talk.
There is however, a more dynamic way of making the connection
between the living and the dead,
using an age-old biological conundrum.
Which came first, the dinosaur or the egg?
There will always be a big market for fossils, but their value
in trying to understand evolution does have a limit.
If you really want to see evolution at work,
you can't just rely on fossilised dinosaurs.
But you might find eggs very useful.
Or rather, what's inside them -
embryos.
Embryos possess all the biological knowhow
that species need to develop.
And we've found they also contain information that can connect
creatures alive today to their distant ancestors.
Scientists in the division of evolutionary developmental biology,
or evo-devo, have been tinkering with
certain genes in chicken embryos, exposing un-chicken-like traits,
like teeth, and tails.
These traits are evidence that chickens contain dinosaur DNA
that's no longer needed.
In fact, redundant DNA is pretty common.
In humans, for example, only about 5% has confirmed employment.
We're now trying to figure out what jobs, if any, the rest have.
Because a lot of it no longer appears to be doing anything.
One idea is that a lot of genes have become silent.
So the information is there embedded, but it's not used,
it's switched off or partly destroyed.
And that, in a way, is evidence that organisms are related
and evolution has occurred.
But the jobless workforce doesn't just disappear.
What scientists have discovered is that there is
a sort of genetic hierarchy, with a senior management
that can re-employ, or switch back on, dormant genes.
And this can have some quite unusual consequences.
Inactive DNA can sometimes return to work, which can lead to atavisms,
evolutionary throwbacks like whales with tiny legs.
The evo-devo scientists did a similar thing, deliberately,
but whether they'll actually put dinosaurs back in business,
full time, is largely speculation at the moment.
So the bottom line
is that within every living thing is proof of its own evolution.
Which makes you feel sort of warm, really.
Well, unless you're cold-blooded.
And actually, speaking of things that are cold-blooded,
it does seem that, despite everything we have in common,
we can't help fighting each other.
Planet Earth has been a war zone for millions of years.
It's an arms race between predators and prey.
Predators developed lethal weaponry like semi-automatic teeth.
So prey evolved evasion strategies, like mimicry.
Predators returned fire with protractile claws,
only for prey to hit to back with hi-tech camouflage.
But some species have gone further - chemical warfare.
Pit vipers are cutting-edge killers.
Their venom is haemotoxic, preventing blood from clotting,
and evolves very quickly.
This should make them unrivalled assassins.
But some viper species have a sworn enemy -
the possum.
In 2011, a blood-clotting gene from the Virginia possum
was found to be evolving incredibly quickly,
strengthening its resistance to the viper's bite,
which explains why it can make such a dangerous opponent its prey.
Both creatures are now locked in mortal combat,
because without the possum,
the viper would not have evolved as it did, and vice-versa.
Strategists call this co-evolution,
which sees sworn enemies evolving together.
The prey is getting better at escaping,
and the predator responds in a sort of complementary way
to become better at catching the prey.
So co-evolution is this sort of tit-for-tat
where evolutionary changes in one organism
are going to create evolutionary changes in another.
So, no cheetahs, no gazelles.
No foxes, no hares.
At least, not as they appear today.
War is hell, but good luck trying to evolve as a pacifist.
So, you're born a mutant,
you grow into adulthood,
and you stave off death, at least temporarily,
through natural selection.
Whatever can be next?
Well, you're probably ready to achieve your evolutionary climax -
reproduction.
And, as you go through the world seeking a suitable mate,
the question you'll be asking yourself is this.
Hotness is in the eye of the beholder.
But looks aren't part of the package for all species.
Some creatures measure hotness intra-sexually,
like those who fight for the right to procreate.
Others compete inter-sexually,
attempting to dance... sing...
or buy their way into the arms of the opposite sex.
Mating calls are a very popular approach.
In 2011, a species of water boatman called Micronecta scholtzi
was found to have, pound for pound, the loudest mating call on Earth.
Despite being just 2mm long, it can hit 99 decibels,
proving that size isn't everything.
That's loud enough for humans to hear,
and it illustrates just how dedicated life is to reproduction.
It's how the genes are passed on from one generation to the next,
it's how the gene pool deepens,
and it's how natural history programmes
are able to get away with showing those sex scenes.
You'd think the boatman's vocals would be a dead giveaway to predators,
but he could be what's called a Fisherian runaway.
Named after the biologist RA Fisher, the theory is that his call,
or other traits like the peacock's plumage,
don't seem to help with survival and might even get them killed.
But it's exactly what their partners are looking for.
This leads to a positive feedback loop,
whereby the more pronounced the trait,
the more it's favoured by the opposite sex in each new generation.
A vicious evolutionary circle, with the occasional happy ending.
But you don't have to have sex to reproduce. Yeah.
You could be a simple organism that just...divides.
I can't do that myself, but bacteria can do that, and it's asexual.
Similarly, there are certain organisms like earthworms.
You can chop an earthworm and produce different earthworms.
So we have asexual reproduction, which happens in many organisms,
and in fact in large parts of the tree of life,
they're the rule rather than the exception.
Whatever your strategy, though,
the ultimate evolutionary measure of hotness isn't looks,
or charm, or bruises.
It's if you've got one of these.
BABY SUCKS DUMMY
That of course explains why there are so many of us,
but it doesn't explain why there is such a great variety of organisms.
The world had a lot to do with that, or rather its geography did.
Next question.
What has geography got to do with evolution?
Animals first made landfall hundreds of millions of years ago, sort of.
We now cover the face of the planet.
But this wasn't just the result of our love of travel.
Land masses divide, mountains rise, rivers become lakes,
and when geography gets in the way, it interrupts the gene flow.
Fold in other factors, like an erratic climate,
and you get speciation - new species.
Geographical isolation is the basic and minimum necessity
for a speciation to occur.
The environment here's not going to be identical to here,
so the best traits for surviving here aren't necessarily the best traits for surviving here.
Eventually those changes are significant enough
for us to say those are two different species.
Some creatures disappeared underground.
Many became tree-dwellers. Others went airborne.
A handful returned to the life aquatic,
with some becoming dolphins and whales.
Millions of years of geographical change
has led to a diverse population
that today includes over 5,000 mammals,
10,000 birds and a million-plus insects.
That's out of an estimated 8.7 million species,
and we've only recorded about 1.7 million of those.
And those figures don't take into account all the countless
microscopic bacteria and viruses littered all over the place.
The world truly is a zoo.
But Earth's geography also brought some species back together,
sort of, through convergent evolution.
Sometimes, different creatures can face similar conditions, even in
different parts of the world, and as a result can evolve similar traits.
Insect, bird and bat wings evolved over millions of years,
and at different points in geological time.
But it isn't always that obvious.
Humpback whales and pelicans
both feed by gulping masses of water into their mouths.
This behaviour evolved independently,
but led to a structurally similar expandable lower jaw.
Incredible, for two creatures that are worlds apart...
..sort of.
So that's 8.7 million species,
and of those we know about 1.7.
I mean, obviously it would take
a very, very long time to count them all,
although I wonder, how long did it take for life to become that diverse?
In other words, is life a marathon or a sprint?
According to Darwin, evolution runs at a steady pace,
known as gradualism.
And the track is inclined,
with species evolving over marathon periods.
But anyone trying to use the fossil record to prove this
would find there were obstacles in the way.
One of the main obstacles is the record itself.
Because so much of it is missing, it's very difficult
to determine the speed over a particular period of history.
There is even evidence that, on the face of it at least,
seems to contradict the marathon theory.
Take, for example, the Cambrian Explosion,
a sub-aqua event held about 550 million years ago.
Before this, ocean creatures were primarily soft-bodied,
like sponges, and barely set any records at all.
Then came the explosion, in which all manner of competitors
seemed to burst forth in record time,
perhaps less than 20 million years,
with hardened skeletons and bi-lateral physiques.
The Cambrian Explosion was a period of time when we see
incredibly rapid diversification of animal bodies in particular.
A lot of new species emerged very rapidly in a short period of time.
And there appear to be sudden big changes
in characteristics that the organisms possess.
Suddenly creatures have eyes where they didn't have any eyes at all,
or, you know, some major structure that wasn't seen before suddenly emerges.
We don't fully understand how life became so diverse so quickly.
It could have been the result of an evolutionary arms race,
or an environmental change
that led some species to develop bony skeletons,
which might explain why their records were so well kept.
It was evidence like this, though,
that led scientists to suggest a different pace -
punctuated equilibrium,
in which evolution combines huge leaps forward
together with long periods of rest.
So, which is it?
Well, there might not be an outright winner.
It could have been long steady runs for some,
a faster rate for others and a variety of speeds in-between.
The ultimate fitness workout. Sounds exhausting.
But no matter how fast you live life,
sooner or later, death is going to catch up with you.
And I don't mean on an individual basis.
I'm talking now about species extinction.
Why do species go extinct?
Statistically speaking, you're lucky to be here,
because 99% of all species that have ever lived are extinct.
The dinosaurs folded 65 million years ago,
the last of five mass extinctions,
killing off 75% of life each time.
Man eliminated the dodo,
one of almost 900 recorded species
who've lost big since the year 1,500.
Invasive species are another serious problem,
like the pet Burmese pythons we've let loose in Florida,
who are now threatening several endangered populations.
But however deadly we've become, in terms of geological time
the biggest killer is evolution itself.
It's nothing personal, neither is it in any way pre-meditated.
It's a simple matter of the hand you're dealt, or, if you like,
the inability of species to adapt to the world around them.
One of the worst hands a species can be dealt
is a change in environment.
When that happens, the large, slow-breeding ones are normally the first to go.
Lack of genetic diversity can also be an issue,
especially for small populations.
The smaller the population gets, just from a purely statistical
point of view, the less likely they are to be different form each other.
For example, if you're on an island, you can only mate
with other members of the population on the island
and they may all have similar characteristics,
so your offspring are all going to have similar characteristics.
There's little raw material for natural selection to work with,
and so this can lead to extinction.
These natural causes have generated an estimated background extinction rate
of roughly one species per million,
per year, for the last 3.5 billion years.
Thanks to us, the rate may now be more than 1,000 times that.
But we'd do well to remember two things -
when it comes to extinction, luck has very little to do with it,
and the house always wins.
Extinctions, it seems,
are simply a fundamental part of the evolutionary process.
But modern science has gone beyond
just trying to understand that process.
And one area of research in particular
has thrown up something of a blockbuster question.
Can we create life?
In 2011, Japanese and Russian scientists
announced a plan to resurrect the woolly mammoth,
attempting to turn science fiction into science fact.
The plan, broadly speaking, is to inject DNA from a frozen mammoth
into the egg of its closest living relative, the elephant.
Then, they'll insert the egg into a female elephant's womb,
where, fingers crossed, it will develop as a baby mammoth.
Sounds complicated...because it is.
If the DNA isn't perfectly intact,
they'll be back to the drawing board.
But even if they get things right,
there's still no guarantee it will work.
Stay tuned, though,
because the scientists say mammoths could be returning to Earth by 2016.
Not all attempts to create life are quite so, well, mammoth.
In 2010, US scientists produced the world's first synthetic life form,
a copy of a bacterial species, using man-made DNA.
They essentially took an empty bacterial cell,
took the DNA that existed in it, flushed it out,
and replaced it with synthetic strands of DNA that essentially
have been sort of stitched together to produce a functional DNA molecule.
When they did that, what happened was that the cell acquired
all the characteristics that were coded for by the new DNA that had been put in,
which is pretty amazing.
OK, it doesn't look like much, and it wasn't really NEW life.
Like any copy, it was based on an original.
And, like the mammoth project,
the artificial element required an organic host.
In this case, an empty bacterial cell.
Producing something totally original,
self-replicating molecules, with a novel genetic code,
that doesn't require a host organism,
is still science fiction at the moment.
But if it ever becomes science fact, it'll be an instant classic.
Evolution 2.0.
Of course, the big difference is, in part two,
it'll be scientists wanting to create life.
And that brings us to the final thing you need to know -
evolution does not in itself have a goal, and it never has.
Animals, plants, even bacteria - they're not trying to be perfect,
they're just trying to make the best
of whatever the world throws at them.
And when you think of it like that,
it sort of takes the stress out of life, doesn't it?
So why not just sit back, relax...
..and try not to get eaten.
Subtitles by Red Bee Media Ltd