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Project: Creatures of Light
Exhibit: iPad
[iPad features-]
What Is Bioluminescence?
Introduction, illustration of a firefly with glowing abdomen
What Is Bioluminescence?
Bioluminescent organisms make their own light by
mixing chemicals. Although all bioluminescence
involves the same three broad types of chemicals,
the exact chemicals differ from species to species.
[Instructions]
Slide to see how organisms make light by mixing
chemicals.
First slide, text pointing to glowing firefly abdomen
1
Fireflies produce light in their abdomens.
Second slide, showing intracellular chemicals
2
They do it by mixing two chemicals in the
presence of oxygen.
Third slide, new text identifies specific chemicals
2
They do it by mixing two chemicals in the
presence of oxygen.
[labels]
Oxygen
Luciferin, the light producer
Luciferase, the helper
Fourth slide, luciferin locks into luciferase
3
Luciferin and luciferase fit together like a lock and
key.
Luciferase [this label remains]
Fifth slide, oxygen reacts with luciferin to produce light
3
Luciferin and luciferase fit together like a lock and
key.
Project: Creatures of Light
Exhibit: iPad
Luciferase [this label remains]
Sixth slide, reaction become brighter, more light emitted
4
And then luciferin reacts with the oxygen to produce
light.
Luciferase [this label remains]
How do Fireflies Switch Off and
On?
Introduction, cutaway illustration of firefly light producing cell
How Do Fireflies Switch Off and On?
Producing light takes oxygen. But in fireflies– as in
all insects– 02 naturally seeps slowly and steadily
into the body. If a firefly’s cells are always supplied
with oxygen, why aren’t the insects lit up all the
time?
[Instructions]
To see what happens in a light-producing cell during
one flash, move the slider.
First slide, cutaway illustration of firefly light producing cell
1
Light production happens in specialized cells.
[Label]
Light producing cell
Second slide, zoomed in cutaway illustration of firefly light
producing cell
2
All cells, including those that generate light, are
constantly supplied with 02.
[Label]
Oxygen
Third slide, oxygen in mitochondria in cutaway of light
producing cell
Project: Creatures of Light
Exhibit: iPad
3
When the cell’s energy producers – its
mitochondria (MY-toe-CON-dree-ah) – are using
the oxygen, the firefly stays dark.
[Label]
Oxygen
Energy Producers (mitochondria)
Fourth slide, same as before, but with nitric oxide cloud
4
When a firefly starts flashing, nerve endings trigger
production of tiny nitric oxide molecules.
[Label]
Nitric poxide
Fifth slide, nitric oxide molecules attach to mitochondria
5
These molecules attach to the cell’s energy
producers, acting as a barrier to oxygen.
[Label]
Nitric oxide barrier
Sixth slide, the light-producing structure in the cells, and the
cell itself, emit light
6
The cell’s available oxygen can be taken up by the
light-producing structures.
[Label]
Light-producing structure
Oxygen
Seventh slide, same image as slide 3
7
When the nitric oxide breaks down, oxygen can get
to the energy producers again. The firefly goes dark.
[Label]
Oxygen
Energy producers (mitochondria)
Project: Creatures of Light
Exhibit: iPad
Night And Day
Introduction slide, illustration of a dinoflagellate
Night And Day
Like many animals that live in the ocean, some
dinoflagellates are commuters. They move up and
down in the water, doing different jobs at different
hours of the night and day.
[Instructions]
Slide to see a dinoflagellate in action.
First slide, illustration of dinoflagellate near the surface, during
the day
1
In the morning, they rise to the surface to soak up
sunlight.
Second slide, orange border around dinoflagellate
2
They spend the day storing energy from the Sun in
carbon compounds– the process known as
photosynthesis.
Third slide, yellow border around dinoflagellate, particles in
water
3
In the evening, they sink down to waters richer in
nutrients.
Fourth slide, same pic as slide 3
4
All night long, they produce light-making chemicals
and flash brightly when they are disturbed.
Day In, Day Out
Introduction slide, illustration of a squid
Day In, Day Out
Some bioluminescent bacteria form relationships
with animals, receiving shelter and nutrients in
exchange for their light. The species Vibrio fischeri
Project: Creatures of Light
Exhibit: iPad
lives in the light organ of the Hawaiian bobtail squid.
[Instructions]
Slide to see how the squid and bacteria cooperate
every day.
First slide, close up illustration of the squid by the ocean floor
1
In the daytime, the squid hides in the sand of the
ocean floor.
Animations of the squid burying itself in the dirt, followed rthe
second slide, a cutaway pick of the buried squid
2
Bioluminescent bacteria multiple inside its light
organ.
[Label]
Light organ
Third slide, same as second slide, but dark
3
By nightfall, the bacteria have reached a quorum–
that is, a high concentration– and their light turns
one.
[Label]
Vibrio fisheri
Fourth slide, glowing squid floating in the water
4
With its belly glowing, the squid rises to the surface
to hunt.
Fifth slide, the squid is dimmer, floating in the water
5
The squid can expand or contract tissues around its
light organ, adjusting its light to match the downwelling moonlight.
Sixth slide, same picture as the 5th slide
6
The squid is well camouflaged against predators
Project: Creatures of Light
Exhibit: iPad
below.
Seventh slide, the squid is glowing again
7
At sunrise, the squid pumps out about 95 percent of
its bacteria, and the light turns off.
Eighth slide, the squid is buried in the sand again
8
The squid drops back down to the bottom, and
buries itself in the sand.
Hiding in Light
Introduction slide, illustration of down-welling light
Hiding in Light
Many creatures use bioluminescence to blend into
the dim sunlight that comes from above. Called
counterillumination, this trick lets the organisms
hide in plain sight.
[Instructions]
Slide to see how creatures hide with
counterillumination.
First slide, black silhouettes of fish
1
In the ocean, dim sunlight filters down from above.
To a predator looking up from below, the view
overhead is like our view of the evening sky.
Second slide, more silhouettes of fish
2
Prey can be spotted as dark shapes against this
lighter background.
Third slide, counterilluminated fish with glowing belly
3
But some animals have a solution: spots of light on
their lower bodies.
Fourth slide, same as 3rd slide, but with dimmer light
Project: Creatures of Light
Exhibit: iPad
4
which they can adjust to blend in with the downwelling light.
Fifth slide, shark silhouette from below
5
Predators also use counterillumination for deception.
Sixth slide, darker shark silhouette
6
Lights on the belly of the cookie cutter shark shrink
its silhouette, so the shark appears small and
harmless to potential prey.
What Is Quorum Sensing
Introduction slide, illustration of a squid
What Is Quorum Sensing?
Some bacteria colonies live in special light organs of
animals. They begin glowing in unison when the
colony reaches a certain size. The bacteria can
calculate the size of the colony through a process
called quorum sensing.
[Instructions]
Slide to see how quorum sensing leads to glowing.
First slide, illustration of bacterium and a particle of messenger
chemical
1
Individual bacteria release a messenger chemical
that sends a signal to neighboring bacteria.
[Label]
Messenger chemical
Second slide, more bacteria, more messenger chemical
2
As the number of bacteria in a small area goes up,
levels of the messenger chemical also rise.
Third slide, even more bacteria and messenger chemical
Project: Creatures of Light
Exhibit: iPad
3
Eventually, when the population of bacteria reaches
a big enough size, or quorum, the amount of
messenger chemical reaches a tipping point.
Fourth slide, ever more bacteria and chemical, and they start
emitting light
4
At this tipping point, all the bacteria finally get the
message, and begin to glow all at once.
What Is Fluorescence?
Introduction slide, illustration of fluorescent coral
What Is Fluorescence
Instead of bioluminescence, many organisms use a
process called fluorescence to glow. This involves
special pigments that make low-energy light out of
high-energy light
[Instructions]
Slide to see how organisms use light to glow.
First slide, illustration of bioluminescent reaction
1
While bioluminescent creatures like fireflies make
light with chemical reactions…
Second slide, fluorescent coral getting irradiated by UV light
2
… fluorescent creatures make light out of other
light.
Third slide, illustration of fluorescent pigment
3
In fluorescence, pigments become excited when
they absorb high-energy light.
Fourth slide, same as the 3rd slide, but the pigment is glowing
4
As the pigments calm down, they release the
leftover energy as low-energy light.
Project: Creatures of Light
Exhibit: iPad
Fifth slide, illustrations of multiple fluorescent items: jellyfish,
insect, crystals
5
Since light fuels fluorescence, fluorescent pigments
only glow when they are under high energy
radiation– like ultraviolet light.
Sixth slide, illustration of a phosphorescent t-shirt with a
“peace” sign
6
Rather than emitting the new light right away, some
pigments store the energy, and release the lower
energy light slowly. This kind of glowing is called
phosphorescence.
Light Shift
Introduction slide, illustration of a jellyfish
Light Shift
How does the crystal jelly make its light?
[Instruction]
Move the slider to see.
First slide, illustration of aequorin and calcium ions
1
The jelly’s light-making chemicals form a molecule
called aequorin, which emits light when it mixes
with calcium.
[Labels]
Aequorin
Luciferase
Luciferin
Calcium ions
Second slide, illustration of aequorin reacting with calcium
ions, glowing flask
2
When aequorin and calcium are mixed in the lab,
they make blue light.
Project: Creatures of Light
Exhibit: iPad
Third slide, same as 2nd slide, but with an illustration of
jellyfish glowing green
3
But in the crystal jelly, the light comes out green.
Why?
Fourth slide, illustration of aequorin interacting with GFP
4
In the jelly, aequorin’s light-making energy is
transferred to another molecule, called the green
fluorescent protein, or GFP.
[Label]
GFP
Fifth slide, same as 4th slide, but with GFP glowing
5
GFP absorbs the energy and emits lower-energy
light, which is green.