Before you read any further, STOP and look outside. Notice all the life that exists around you from the grass and trees to the insects and animals. How did it get here? When and how was life able to thrive here in the biosphere? Well, it was all made possible by an organism you likely see all the time: lichen!
What on earth is a lichen anyway? Lichen are the result of a symbiotic relationship between a fungi and an algae. This means that both the fungi and algae benefit each other and actually need each other to live. Algae cannot live outside of the water, so the fungi provides a protective capsule by hugging the algae. The algae helps the fungi by using photosynthesis to turn sunlight into food, providing the fungi with energy. This is a relationship where both partners benefit.
Lichen were one of the first living things to begin life outside of the oceans and they helped to lead the way for all other life on land. The Canadian shield around 250 million years ago was rocky and bare when the lichens started to slowly climb on. Lichens create acidic enzymes that break rock down and this allowed for minerals and nutrients inside the rocks to create soil over a very long time. This allowed mosses, grasses, and other vegetation to appear next on the Canadian shield and eventually larger trees and shrubs.
There are over 20,000 different species of lichen in the world and it is estimated they cover 6% of the Earth’s surface! Their relationship between fungi and algae allow them to live almost anywhere. You can find lichen living in the scorching hot deserts all the way to the frozen tundra. Lichen never move and they are super slow growing, but this allows them to live a very long time. The oldest lichens, found in the Arctic, are estimated to be 8,600 YEARS OLD! Since they grow so slowly and live so long scientists can use lichen to estimate the age of geological and man-made structures.
Though lichens are able to exist in so many places, like all superheros, they have their weakness too: air pollution. There are some species of lichen that cannot live in areas with poor air quality. This makes some lichens a great bioindicator, a living organism that can help scientists determine if an ecosystem is healthy or not. When there are few lichen living in an area, it is a good sign there is air pollution in that area.
So let’s listen to lichen!
Activity: Lichen Abstract Art
Lichen come in many beautiful patterns and colours. Let’s re-create some of them through abstract art! You will need:
- A sponge and/or tissue paper
- A rock or paper to display your lichen art
The two lichen shapes you can make are called crustose and foliose lichen.
Crustose: These lichens grow flat to rocks and trees and have a spotty rough texture. To make this type of lichen:
- Dip your sponge in paint and dab it on your rock or paper.
- Try layering your lichen art with different colour paints, different shades of the same colour, or use different sponges with larger or smaller holes.
Foliose: These lichens are raised higher off of rocks and tree branches, they look more lobbed. To make this lichen:
- Rip or cut out strips or pieces of tissue paper to represent the lichen.
- Glue your tissue paper on your canvas of choice in a “fingery” shape like lichen.
- Do this until your satisfied with how your lichen looks. Try scrunching or layering the tissue paper after the first layer dries.
- You might want to paint your lichen to add shadows or more colours.