A glowing world… Our natural world has many amazing phenomena. One of the most intriguing has to do with light. Some living things are able to produce their own light, without electricity. And they don’t just do it one way, but two! This unit is a great way to teach students ages 9 to 12 about the difference between bioluminescence and biofluorescence, and get started learning about glowing animals.
Bioluminescence happens when a living thing is able to create light within its own body because of chemical reactions. One of the best-known examples of this is the lightning bug or firefly.
Fireflies use bioluminescence to communicate. They have two chemicals inside their abdomens: luciferin and luciferase. When these two chemicals and some other enzymes interact with oxygen, they produce light. Fireflies take in oxygen through a series of small holes in their abdomen called spiracles and tracheoles. They are also able to control how much oxygen enters their body in order to make the light last longer or burn brighter.
The interesting part is that this light is very efficient and bio-friendly. It is called “cold light” because it does not create heat. This is really important because the firefly’s body would burn up and die if the light were to burn hot. It’s gentle enough that even firefly eggs and larvae are bioluminescent.
But why do they light up? Communication is key. Fireflies may glow to warn away predators. Different species of fireflies also have their own unique blinking pattern so that they can identify others like themselves. And some males use their light patterns to attract females.
But the ecosystem with the most bioluminescent organisms is the ocean. In the deeper layers of the sea where sunlight does not penetrate, fish and other organisms use bioluminescence to communicate and to hunt. Perhaps one of the best examples is the Deep-Sea Dragonfish.
Dragonfish have a long eel-like body. They also have special organs called photophores where they produce light through chemical reactions. These photophores are located along the sides of their bodies and beneath their eyes. The fish use them by blinking a series of light patterns to attract mates, disorient prey, or warn predators. There is also a photophore at the tip of their barbel, which they use to lure prey close to their jaws before ambushing them.
By contrast, biofluorescence is when ultraviolet light or blue light (light with higher energy wavelengths) gets absorbed by a living thing and then is reemitted as a different, lower energy wavelength light. Usually, this is a different color, such as red, orange, or green.
Salamanders and frogs are excellent examples of animals that are biofluorescent. In the deep woods where they live, direct sunlight has a difficult time penetrating the trees. But blue light is abundant. Scientists aren’t sure how they use biofluorescence, but possibilities include communication or to locate each other at night.
Amphibians are more likely to be biofluorescent, while fish are more likely to be bioluminescent. Many insects can glow using one or the other method.
Activities for Learning About Glowing Animals
Here are some of our printable resources for helping your child learn more about how light is produced by living organisms.
Explore fluorescence by creating your own animal art using glow-in-the-dark art supplies.
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- Supplies: black or dark blue construction paper, glow-in-the-dark paint or paint pens
- Directions: Draw a frog or salamander on the paper using your paints. Allow it to dry. “Charge” under lights, then view your scene in a dark room!
- Supplies: an empty mason jar or shoebox, black paint or black construction paper, and glow-in-the-dark play-doh or clay
- Directions: Paint the inside of the shoebox black. If using a jar, you can wrap the back half of it in dark construction paper, or just leave it open. Carefully craft a frog or salamander using your clay/play-doh inside your jar. “Charge” it under lights, then view it in a dark room!
Puerto Rico is home to the brightest bioluminescent bay in the world. Mosquito Bay is found on the island of Vieques, off the east coast of Puerto Rico’s mainland.
Activity: Print our Mosquito Bay/Dinoflagellates map & writing sheets. Use an atlas to help you find Puerto Rico and help you label the places listed on our map worksheet.
Then have your children research and learn about Mosquito Bay and the dinoflagellates that make it bioluminescent. Use our writing pages to describe its location and the conditions that make this phenomenon possible.
A LOT of sea life is bioluminescent. Especially organisms that live in the Midnight and Abyss Zones. These organisms use light to hunt, warn, and attract other sea life.
Activity: Print our Bioluminescent Sea Life Coloring Page then find the glowing creatures listed and color them in.