Suppose I said

that, with just a few changes in your genes,

you could get a better memory --

more precise,

more accurate and quicker.

Or maybe you'd like to be more fit, stronger,

with more stamina.

Would you like to be more attractive and self-confident?

How about living longer with good health?

Or perhaps you're one of those

who's always yearned for more creativity.

Which one would you like the most?

Which would you like, if you could have just one?

(Audience Member: Creativity.)

Creativity.

How many people would choose creativity?

Raise your hands. Let me see.

A few. Probably about as many as there are creative people here.

(Laughter) That's very good.

How many would opt for memory?

Quite a few more.

How about fitness?

A few less.

What about longevity?

Ah, the majority. That makes me feel very good as a doctor.

If you could have any one of these,

it would be a very different world.

Is it just imaginary?

Or, is it, perhaps, possible?

Evolution has been a perennial topic

here at the TED Conference,

but I want to give you today

one doctor's take on the subject.

The great 20th-century geneticist,

T.G. Dobzhansky,

who was also a communicant

in the Russian Orthodox Church,

once wrote an essay that he titled

"Nothing in Biology Makes Sense

Except in the Light of Evolution."

Now if you are one of those

who does not accept the evidence for biological evolution,

this would be a very good time to turn off your hearing aid,

take out your personal communications device --

I give you permission --

and perhaps take another look at Kathryn Schultz's book on being wrong,

because nothing in the rest of this talk

is going to make any sense whatsoever to you.

(Laughter)

But if you do accept

biological evolution,

consider this:

is it just about the past,

or is it about the future?

Does it apply to others,

or does it apply to us?

This is another look at the tree of life.

In this picture,

I've put a bush with a center branching out in all directions,

because if you look at the edges

of the tree of life,

every existing species

at the tips of those branches

has succeeded in evolutionary terms:

it has survived;

it has demonstrated a fitness

to its environment.

The human part of this branch,

way out on one end,

is, of course, the one that we are most interested in.

We branch off of a common ancestor

to modern chimpanzees

about six or eight million years ago.

In the interval,

there have been perhaps 20 or 25

different species of hominids.

Some have come and gone.

We have been here for about 130,000 years.

It may seem like we're quite remote

from other parts of this tree of life,

but actually, for the most part,

the basic machinery of our cells

is pretty much the same.

Do you realize that we can take advantage

and commandeer the machinery of a common bacterium

to produce the protein of human insulin

used to treat diabetics?

This is not like human insulin;

this is the same protein

that is chemically indistinguishable

from what comes out of your pancreas.

And speaking of bacteria,

do you realize that each of us carries in our gut

more bacteria

than there are cells in the rest of our body?

Maybe 10 times more.

I mean think of it,

when Antonio Damasio asks about your self-image,

do you think about the bacteria?

Our gut is a wonderfully hospitable environment

for those bacteria.

It's warm, it's dark, it's moist,

it's very cozy.

And you're going to provide all the nutrition that they could possibly want

with no effort on their part.

It's really like an Easy Street for bacteria,

with the occasional interruption

of the unintended forced rush to the exit.

But otherwise,

you are a wonderful environment for those bacteria,

just as they are essential to your life.

They help in the digestion of essential nutrients,

and they protect you against certain diseases.

But what will come in the future?

Are we at some kind of evolutionary equipoise

as a species?

Or, are we destined

to become something different --

something, perhaps, even better adapted

to the environment?

Now let's take a step back in time

to the Big Bang, 14 billion years ago --

the Earth, the solar system,

about four and a half billion years --

the first signs of proto-life,

maybe three to four billion years ago on Earth --

the first multi-celled organisms,

perhaps as much

as 800 or a billion years ago --

and then the human species,

finally emerging

in the last 130,000 years.

In this vast unfinished symphony of the universe,

life on Earth is like a brief measure;

the animal kingdom,

like a single measure;

and human life,

a small grace note.

That was us.

That also constitutes the entertainment portion of this talk,

so I hope you enjoyed it.

(Laughter)

Now when I was a freshman in college,

I took my first biology class.

I was fascinated

by the elegance and beauty of biology.

I became enamored of the power of evolution,

and I realized something very fundamental:

in most of the existence of life

in single-celled organisms,

each cell simply divides,

and all of the genetic energy of that cell

is carried on in both daughter cells.

But at the time multi-celled organisms come online,

things start to change.

Sexual reproduction enters the picture.

And very importantly,

with the introduction of sexual reproduction

that passes on the genome,

the rest of the body

becomes expendable.

In fact, you could say

that the inevitability of the death of our bodies

enters in evolutionary time

at the same moment

as sexual reproduction.

Now I have to confess,

when I was a college undergraduate,

I thought, okay, sex/death, sex/death, death for sex --

it seemed pretty reasonable at the time,

but with each passing year,

I've come to have increasing doubts.

I've come to understand the sentiments of George Burns,

who was performing still in Las Vegas

well into his 90s.

And one night, there's a knock at his hotel room door.

He answers the door.

Standing before him is a gorgeous, scantily clad showgirl.

She looks at him and says,

"I'm here for super sex."

"That's fine," says George, "I'll take the soup."

(Laughter)

I came to realize,

as a physician,

that I was working toward a goal

which was different from the goal of evolution --

not necessarily contradictory, just different.

I was trying to preserve the body.

I wanted to keep us healthy.

I wanted to restore health from disease.

I wanted us to live long and healthy lives.

Evolution is all about passing on the genome

to the next generation,

adapting and surviving

through generation after generation.

From an evolutionary point of view,

you and I are like the booster rockets

designed to send the genetic payload

into the next level of orbit

and then drop off into the sea.

I think we would all understand the sentiment that Woody Allen expressed

when he said, "I don't want to achieve immortality through my work.

I want to achieve it through not dying."

(Laughter)

Evolution does not necessarily

favor the longest-lived.

It doesn't necessarily favor the biggest

or the strongest or the fastest,

and not even the smartest.

Evolution favors

those creatures best adapted

to their environment.

That is the sole test

of survival and success.

At the bottom of the ocean,

bacteria that are thermophilic

and can survive at the steam vent heat

that would otherwise produce, if fish were there,

sous-vide cooked fish,

nevertheless, have managed

to make that a hospitable environment for them.

So what does this mean,

as we look back at what has happened in evolution,

and as we think about the place again

of humans in evolution,

and particularly as we look ahead

to the next phase,

I would say

that there are a number of possibilities.

The first is that we will not evolve.

We have reached

a kind of equipoise.

And the reasoning behind that would be,

first, we have, through medicine,

managed to preserve a lot of genes

that would otherwise be selected out

and be removed from the population.

And secondly, we as a species

have so configured our environment

that we have managed to make it adapt to us

as well as we adapt to it.

And by the way, we immigrate and circulate

and intermix so much

that you can't any longer

have the isolation that is necessary

for evolution to take place.

A second possibility

is that there will be evolution of the traditional kind,

natural, imposed by the forces of nature.

And the argument here would be

that the wheels of evolution grind slowly,

but they are inexorable.

And as far as isolation goes,

when we as a species

do colonize distant planets,

there will be the isolation and the environmental changes

that could produce evolution

in the natural way.

But there's a third possibility,

an enticing, intriguing and frightening possibility.

I call it neo-evolution --

the new evolution

that is not simply natural,

but guided and chosen

by us as individuals