This episode is supported by Curiosity Stream.
For centuries, humans have been harnessing chemistry to create explosive awe inspiring
light shows.
But our celebrations aren’t Earth’s only dazzling light displays.
Nature’s got fireworks of its own…
[OPEN]
Nearly all life on Earth is ultimately powered by light.
But some special species have figured out how to make light for themselves.
Our planet is full of creatures with the ability to bioluminesce.
Not every animal that glows is bioluminescent.
Animals like these jellyfish are fluorescent.
They only glow after absorbing and emitting other light.
But bioluminescent species carry their own light factories.
Inside their bodies, chemicals called luciferins, along with oxygen and some ATP, react together
with the help of an enzyme called luciferase to give off light.
And you can see this chemistry in action right before sunset on a summer night.
Fireflies aren’t really flies at all, they’re beetles.
Their nightly dances are stunningly beautiful, but that light show is really one big mating
display.
It’s usually male fireflies that do the flying, while females sit and enjoy the show.
Firefly bioluminescence is a form of sexual selection.
Like a peacock’s feathers or an elk’s antlers, brighter and more intense light signals
you’re a healthy mate with good genes.
Of course, like any dance, you have to get the timing right too, and each species has
their own rhythm.
Males of the species Photinus pyralis always flash while flying up.
If she sees his signal, two seconds later, the female blinks in return.
The male glides down then blinks again, homing in on the female’s response and hoping there’s
a mating opportunity waiting for him when he gets there.
But the line between love and death is a fine one.
Females of the genus Photuris have earned the name “femme fatale” fireflies.
They mimic the flash timing of other species’ females, luring in unsuspecting suitors, and
eating them.
They harvest chemicals from the males’ bodies to repel their main predator: spiders.
From fungi to worms, this ability to create chemical light has evolved independently many
times, but to really appreciate nature’s firework show, we have to take a plunge.
Oceans contain 99% of the habitable space on the planet, and most of Earth’s bioluminescence
happens down there.
It’s hard to believe, but researchers estimate three-fourths of all species in the ocean
produce their own light, and at every depth.
Only they don’t just use it to find mates.
These are dinoflagellates, tiny marine plankton found throughout Earth’s oceans.
You can’t see them right now, but watch this.
If they’re disturbed at night, they light up!
They make a different luciferin molecule than fireflies, one that emits blue light.
This blue glow can be seen in crashing waves and in the wakes of ships, but why would a
creature too small to swim from a predator want to advertise its location?
Ever heard the saying “the enemy of my enemy is my friend”?
If a shrimp or other predator disturbs the dinos, light can attract the attention of
things that eat shrimp.
It’s like a chemical burglar alarm.
Ocean species put bioluminescence to use in dozens of ways!
Some prey species, like this shrimp, spew luminescent clouds, escaping behind a shiny
smoke screen.
Some squid even sacrifice entire limbs so the rest of them can escape, like light-up
lizard tails,
Bioluminescence is even used for camouflage, matching the color and brightness of sunlight
to mask a silhouette from below.
Of course, hunters have mastered the light game too.
Some use it as a lure, while some flash to stun their prey.
Some, like this deep sea drag onfish, even use bioluminescent patches as searchlights
in the dark.
What’s incredible is that even in habitats where the sun almost never reaches, light
has become an essential part of life.
Whether you’re at the bottom of the ocean or your back porch, you can appreciate some
of nature’s brightest ideas.
Stay curious.