Pairing Up In a lichen, the fungus is the bigger partner. It builds a shelter for the alga. I can really see this when I look at a lichen under a microscope. Strands of the fungus almost look like the bars of a cage. Hiding inside the fungus, I can see specks of algae. T e alga is the smaller partner. Yet it has a


huge job. It makes food. Like a plant, the alga is packed with chlorophyll. T e chlorophyll captures energy from the sun. It turns the sun’s energy into food. T is food then feeds both the fungus and the alga.


Helping Out T e teamwork between the fungus and alga is a kind of symbiosis, or partnership. It’s called mutualism. Both partners benefit. Here’s how. Some kinds of fungus can make their own


food. T e kind of fungus in a lichen, though, can’t. It would starve on its own. It needs the alga to get food. T e alga can survive by itself, but it can


only live in humid, or damp, places. Most algae live in water. When an alga teams up with the fungus, though, it can live almost anywhere. I’ve found lichens growing on cactus spines.


I’ve spotted them growing on plastic bottles and rusting cars. In the Galápagos, they even grow on the backs of giant tortoises. Lichens also can live in the most extreme


places. T ey grow in the hottest deserts. T ey also grow in the coldest ones, like in the Arctic. Some lichens have even survived being launched out into space.


Fun Fact: Some lichens in the Arctic may be 9,000 years old.


Strands of a fungus hold a speck of algae. Together, these two organisms form a lichen.


Lichens can live in unusual places. This one grows on the paint of a truck.


JANUARY–FEBRUARY 2014 21


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