we don't typically ponder the elegance
of bugs especially the annoying ones
but scientists and engineers have come
to realize they are actually mechanical
marvels
nothing we humans have ever built even
comes close
in fact a growing field of engineering
called biomimetics is making
breakthroughs by mimicking biology
for example
studying the eyes of flies
led to the development of advanced
optical sensors
the physics of dragonfly wings allowed
increased efficiency of wind turbines
cockroach mechanics paved the way for
increased agility in robots
a honeybee algorithm helped to optimize
the internet
and the tiny planthopper is helping
scientists to maximize the strength and
rotation of
gears
what
gears
in a bug
that one got my
attention i thought humans invented
gears
those perfectly precise
interconnected drivers that have
transformed machinery for centuries
well it turns out that biology is far
ahead of our engineering
the plant hopper launches like a rocket
and can jump more than a hundred times
its body length
that's like an olympic long jumper
hurtling across not one but two football
fields
using special cameras
scientists at cambridge university
discovered that the planthopper
coordinates the motion of its legs with
these incredibly precise gears
making long leaps accurately requires
that the legs be in perfect sink if one
leg flexed even a fraction of a
millisecond before the other the insect
would lose power and tumble erratically
as one leg begins to move the
interacting gears start the other leg
too with the teeth engaged the gears
spin at a whopping 50 000 teeth per
second and the bug is propelled with
maximum power and coordination
as science learns more about the
structures of living organisms
we seem to be finding limitless examples
of mechanisms that are both precise and
purposeful
both remarkably configured and
beautifully functional
so what accounts for the stark
purposiveness of the machinery of life
for over 150 years evolutionary
biologists have thought they had an
explanation
darwin's theory of evolution
darwin proposed that all life evolved
simply by variation
that occurred within a species
then
natural selection determined which one
survived
for example let's look at bear evolution
scientists believe the polar bear in the
arctic evolved from ancestral brown
bears in adjacent regions
here's a possible scenario
many thousands of years ago a bear cub
was born with a mutation in its dna
the change gave the lucky bear the
ability to eat a high fat diet
like seal blubber
so the mutant bear and its descendants
could hunt seals for food
generations later a baby bear was born
with another mutation that altered its
color
the subsequent change from brown fur to
white was useful in the snowy
environment for sneaking up on prey
more such helpful mutations followed
so variation in the ancestral species of
the brown bear followed by natural
selection for the harsh snowy
surroundings
were responsible for building the
magnificent polar bear in small steps
we can see fascinating evolutionary
changes in species
but modern science now knows something
that darwin didn't know
that the changes in a species that we
can see
are driven by molecular changes in genes
and dna that we can't see
at least not with our eyes
now for a few sixty four thousand dollar
questions
what precisely are those helpful
mutations in dna
how exactly do genes change
if brown bears can give rise to polar
bears does that mean we'll see future
genetic changes making new species
will we humans mutate into super-powered
x-men
[Music]
we'll open that box in our next episode
on the effects of mutation
[Music]
you