Eight body plans of the animal kingdom: Tierney Thys at TEDxKids @SMU 2011

Tierney Thys is ardent ocean scientist, conservationist, media producer and National Geographic Emerging Explorer. She made films for National Geographic Television for more than ten years. In this talk, she details eight of the basis body plans in the animal kingdom that cover the vast majority of the world's fauna.

Wow! It's so great to be here!

I'm so happy to see you guys.

Arguably, one of the most disruptive
events in the history of the planet

has got to be the rise
of the animal kingdom.

Definitely.

I mean, here is Earth, simmering along,
minding its own, single-cell business

for nearly four billion years,
and some group of restless cells

comes together and decides
to become multi-cellular metazoa and well...

the neighborhood's
never been the same since, has it?

And we have a remarkable
diversity of animals

with whom we share the planet, don't we?

Millions of species swimming,
scurrying, slipping around,

seemingly endless forms,
most beautiful.

How do you make sense of it all?

Well, it may just help to know
that 99% of all animal life

fall into just eight major groups.

Eight body plans.

Scientists call these "phyla".

And if you know these eight plans,
you've got an incredible grasp

of the constraints and freedoms
of the animal world.

And there's something special
about these eight phyla.

While species go extinct every day,
these phyla have prevailed and persisted

for over 550 million years.

Every mass extinction
the planet has mustered,

they've managed to make it through.

So who are these amazing methuselahs?

Let's look at plan 1: the sponges.

These are Earth's first
true blue animals.

They scripted that vital language
for single cells to work together

with other cells for a common cause,
in this case, pumping.

So hail Mother Sponge!

It sucks, it pumps,
it's a mother of us all.

And you know, some of us have a problem
being descendants from apes. Well...

So, plan number 2: the cnidarians:
anemones, jellies and corals.

These were the first guys to put muscle
and nerve together into a body plan,

and with that, we get animal behavior.

They're characterized by a round body,
radially symmetric,

and little stinging cells called "cnidae".

If any of you have been
stung by a jellyfish,

you know what I mean,
they pack a punch.

So these were the first guys
to coin animal behavior.

Okay, our next body plan –
look at those little anemones –

– are the platyhelminthes.
Very contemptuous phylum,

many biologists don't feel
it's a true phylum,

but comprised of many different phyla,

and so right now the animal tree
is being shaken right at its roots.

But what you need to take home
from this representative body plan is that,

here we see the first representation
of a left-right symmetry.

Bilateral symmetry,
which all complex animals have.

And a concentration of sense organs
right at one part of the body.

The makings of a head,

and with a head you can have
directed animal behavior,

and hunting.

This is also where we think
animals first started

to get a threshold level
of genetic complexity

and pole body patterning genes
called Hox genes.

And that, coupled with the right
environmental conditions,

and serendipitous fossilization,

catalyzed its incredible
radiation of animal diversity

best known from the Cambrian explosion.

Also in this group is, we think,
the appearance of the first penis.

And as I've raised that subject,

I have to talk about one modern
representative, the turbellarians.

These guys have not one,
but two penises that are hypodermic.

And they joust with them.

And the first one to jab its sperm
into the other gets to be the boy,

while the jab-ee gets to be the girl.

And this remarkable behavior
is aptly called penis-fencing.

Go figure.
(Laughter)

OK, moving on to the fourth:
we have the annelids.

These animals have
a body cavity called the coelom.

And they're known by having these
little rings running down their bodies.

What these guys brought
into the animal world

was the ability to penetrate into the soil,
bring oxygen in and release carbon dioxide.

And releasing carbon dioxide
actually helped

to heat the planet up and make it
more livable for other life.

Now we've got too much CO2,
but at the time,

this was really an important thing
that the annelids brought to the planet –

Bioturbation. Okay.

Our next plan we've got are the mollusks.
Amazing phylum.

Tiny little shelled animals to giant squid.

All characterized by a single slimy foot.

And what the mollusks show us,
most of them are shelled.

And we can see in the mollusk phylum
is this arms race escalation,

with shells becoming
more increasingly complex

in response to more complex predation
from other phyla,

so they kind of exemplify
an arms race escalation,

with some of them actually
doing away with the shell completely,

trading it for smarts and psychedelic skin
that we see in the squid and the octopus.

And these are the guys
who can change color

and texture of their skin
in split-seconds,

the rockstars of the mollusk phylum.
Gotta love these guys. (Laughter)

And they can even be bipedal!

Okay, our next phylum are
the echinoderms, the spiny-skinned guys.

The sea stars, sea urchins,
and sea cucumbers.

And they're characterized by
an internal skeleton of little plates

that can lock together with
very little energy expenditure.

And underneath are these tube feet
that allow them to move

and shuttle food to their central mouth.

Now, these are a complex animal,

but they decided to do away
with bilateral symmetry,

they have a five-part symmetry.

And they have no brain.

And they seem like they don't do much,
they just sit there on the sea floor.

But you speed them up in timelapse and
you see that they're incredibly industrious.

And they actually comprise the bulk
of the biomass in the deep sea environment.

Very successful body plan.

Our next one, the true rulers
of the planet, the arthropods.

Now, if you look at all the animals,
the arthropods comprise the bulk.

Eighty percent are arthropods.

If you added up the biomass of humans,
they are 300 times the biomass of all humans.

And most of them are insects!

Did you know that four out of five
animals have six legs?

So, these are the first guys
that walked out of the ocean

and started to explore at land.

They were the first ones
that took to the skies.

100 millions of years before the birds
ever thought of doing such a thing.

So, what is the secret to their success?

How are they able to be in
every environment imaginable?

Well, it has something to do
with that outside skeleton,

their exoskeleton.

And their diversity of appendages
down their body,

like a little Swiss army knife.

They can have multiple antennae,
multiple legs, multiple wings,

multiple reproductive organs,
it's just an amazing attribute

that allows them to infiltrate
every habitable space on the planet.

And the last phylum, the chordates.

This is, of course, where we originated
over 550 million years ago.

And it's characterized
by having a spinal cord,

right there you see in pink,
that blossoms into a brain in vertebrates,

and underneath a notochord,

which turns into a bony spinal column
in the vertebrates as well.

And this is all the guys that
make the silver screen all the time.

The mammals, and the amphibians,
and the reptiles, and of course, the fish.

The bulk of the chordates are the fishes.

And these are all the guys
we know and love.

And of course, the fish –

that's one of my favorite fish,
the mola mola.

And it includes our kin,
our land-loving hominids.

These are my little ones.

So that's the basic eight,

and, I think, to recap,
why don't we do that with a song?

Alright, you guys ready? Okay.

And now, a song.

The sponges started everything,
pumping up a storm,

...among the ruckus,
the rest of us was born.

Cnidarians muscled up,
mixed nerves into the potion,

and with that quick addition
got us brand-new locomotion.

The flattish worm-like hunters
got a head and then some traction,

and with some senses and a penis – 
Oooh! – scored some action.

The shape of life, yeah.

And here we have penis fencing
in flagrante delicto.

The shape of life, yeah...

Now, being male and female,
that just works out great,

anybody in the world
can double as your date.

Then all hell broke loose
and the other plans appeared.

The Cambrian exploded,
launched the world into high gear.

The annelids took to the dirt
and bioturbatin'.

The mollusks took to fighting
and arms race escalating.

Echinos said, "The heck with this,
we're better off instead

taking life into the slow land,
lopping off that head."

Arthros stepped onto the land
and ruled, that ain't no mystery,

till bonehead chordates followed
and soon would rewrite history.

The shape of life, yeah...

Okay, very good!
(Applause)

So why study these mostly
slimy, spineless critters

with whom we co-pilot spaceship Earth?

Well, were it not for them,

none of us would be strutting and
fretting our ten minutes upon this stage.

It's the animal life and
all the life that came before us

and with whom we share this planet
that not only set the stage,

but created the very stage for all life
to flourish in the future.

And I can't put it any more eloquently
than E. O. Wilson, who says:

"Humanity is exalted, not because
we are so far above every thing living,

but because knowing them well
elevates the very concept of life."

Thank you.

(Applause)