We all dream from the time
we're little kids about
being able to fly, right,
and what that would be like.
While humans can fly,
it's still a work in progress.
Insects, birds and bats
have had millions of years
to work out the kinks.
So how did flight evolve in nature?
And how can our understanding
of its evolution and mechanics
improve our aerial abilities?
Let's take flight to find out.
Insects evolved flight
about 400 million years ago.
When insects began to fly
there was nothing else in the air.
Flight was an incredible
evolutionary innovation
that really led to insects'
success on the planet.
How flight evolved in insects
is one of the biggest unknowns
in evolutionary biology.
It's huge mystery.
One way to approach the question is
to look at wingless insects today
and ask: Can they fly?
And that's an odd question, right?
How can a wingless insect fly?
But are they capable of
controlled aerial behavior?
In the last ten years we've done
a lot of experiments
in tropical rainforests,
climbing trees,
grabbing primitive kinds of insects,
and throwing them out of trees.
We want to see what they do
while they're in midair.
And the amazing thing is
for a whole range of things,
if you drop them upside-down,
they right themselves in mid-air,
like a falling cat.
And then they start to glide.
They have targeting and gliding
and very sophisticated aerodynamic
control and maneuverability
in the complete absence of wings.
So this is an amazing discovery.
Researchers call this
the "tree down" hypothesis.
It's an aerial origin.
They are also competing
terrestrial origins and these hypotheses
are not just true for insects,
but for birds,
and their ancestors, dinosaurs, as well.
There's quite a bit of discussion
and debate about exactly how
flight evolved in dinosaurs.
There are a couple different hypotheses.
One, we like to think of as
the "ground up" hypothesis,
where birds might run
along the ground
and be able to open their wings
and take a couple flaps
and maybe move a little bit
and get airborne.
And flight evolution in these
larger creatures seems to have
something to do with these things.
Probably the most important characteristic
that birds would have had to evolve
for flight is feathers.
And we now believe,
looking at fossils,
that feathers evolved even before flight,
probably for keeping them warm
and for insulation against cold
or for temperature changes,
in sexual selection,
and to wow their mates.
Even though the origins of flight
are a bit fuzzy, we understand
a lot more about how these
magnificent creatures fly now.
The primary ways that birds fly
is that they have a downstroke,
which gives lift,
but then they have to get
the wing back up,
without getting too much resistance,
so that they can be ready
for the second stroke.
Now some birds fly very differently,
for example, hummingbirds.
And in hummingbirds, they actually
get lift on both strokes,
and that's why they're able to hover.
Because they can get lift
when they flap forward,
but then they can actually
turn the wing and flap backward
and get lift when
they're flapping backward.
And if you watch our penguins
up in the penguin tank,
they kind of do the same thing
when they're swimming.
So they're flying like this
through the water.
And we're still learning about flight.
We do behavioral and
aerodynamic work on birds
and then we release all birds
that we capture.
Anything that the hummingbird
can do in the air,
we are interested
in figuring out what it's doing,
describing it,
and then mechanistically trying
to figure out how it's doing it.
The work Robert and his team
do in their lab influences engineering
for better manmade flight.
There is an entire emerging
field of technology called
micro air vehicles, whereby
people are seeking to miniaturize
flying platforms for the purposes
of surveillance, or pizza delivery,
and many other kinds of
interesting services.
Who knows how human flight
might evolve.
Insects have been flying
for probably 400 million years,
and we've been flying
for about 100 years.
So in some ways
they can do so many things
better than we can.
So we still have a lot to learn
from the ways that they've evolved
to overcome the obstacles
in dealing with the same kind
of natural forces and physical forces
that we have to overcome to fly.
So we have a lot to learn
from the insects.