Take a look around. Look high and low. How many living things do you see? Grass covers the yard, flowers bloom, trees shade with their leaf-covered branches. Can you hear the buzz of insects? Did a critter scuttle by? The longer you look, the more you see. The world is a busy place.
But what about all the living things you cannot see? A whole other world lives under your feet. How many different animals live underground? Believe it or not, one-third of all the animals in the world live underground! Some are so small you can’t see them without a microscope, but they are alive and thriving.
Think about scooping a spoonful of ice cream. Yum! Now imagine that same size spoon holding a scoop of soil. How many species do you think are in that one scoop? More than 100? More than 1,000? That spoon can hold 10,000 different species. That equals 1 billion microbes! Now imagine holding a handful of soil. Or go outside and grab one if you can. That handful of soil can hold more microbes than there are humans in the whole world! Wow! Another world held right in your hands!
A dragonfly zooms over a pond. A lightning bug flashes as it flies by. Cicadas buzz loudly in trees. These insects live above the ground. Or do they?
We see them zooming and flashing and hear them buzzing once they are adults. But they spend their time as eggs and larvae underground. In fact, they spend longer below ground than above it! Can you think of any other creepy crawlies that spend most, or all, of their lives below the ground?
How about worms? Sometimes they wriggle above ground when heavy rains fall. Or when a robin yanks them out for dinner. But mostly they live below, eating decomposing material and pooping it out as nutrients for plants to absorb. They burrow through soil making pathways for air and water that help plants grow while trying to avoid hungry moles.
Have you ever seen a mole? How about a long trail of raised soil, like a thick dirt hose winding through the grass? Moles rarely, if ever, venture above ground. Instead, they dig tunnels underground searching for food, like worms. They dig burrows — different rooms to live in (bedroom) and keep their babies safe (nursery) and store food (kitchen). What other animals live in burrows below the ground? Do they spend more time above or below?
Words to know
Absorb: To take in or soak up by physical or chemical action.
Burrow: A hole or tunnel dug by an animal.
Decompose: To decay or become rotten.
Larva: The immature form of an insect.
Microbe: A microorganism.
Microscope: An instrument for viewing view small objects.
Mycelium: The vegetative part of a fungus that consists of a network of fine white fibers.
Can you think of anything besides animals that live above and below the ground? Plants! Stems, branches, leaves and fruit wave in the wind in every direction we look. Above the ground, blades of grass tickle feet, tree canopies shade the sun and flowers scent the air. But the parts of the plant you can see, no matter how big, are really just a small portion of that plant.
Below the ground, roots stretch deep and wide. Many plants grow as big below ground as above. In the case of native plants, their roots can reach far deeper into the soil than their stems stretch to the sky. For example, black-eyed Susan, a native plant, can grow 2 feet to 3 feet tall, but their roots can extend more than 6 feet deep!
Separate from plants and animals, fungi also live above and below. Mushrooms pop out of the ground, especially in the fall. You can see them for a while, but, like the fruit of plants, they often only last for a short time.
Below the ground, a different story unfolds. Mycelium is the main part of the fungus. Like the roots of plants, it branches out underground. The spiderweb-like strands form a mat as they spread. They absorb nutrients to feed the fungus. Often the roots of plants and mycelium of mushrooms are sharing food, like visiting a potluck dinner.
Action unfolds above the ground right before your eyes. But remember below your feet another world grows and thrives unseen. Next time you go exploring, look for signs of life below. Imagine yourself burrowing deep tunnels through the soil or tracing the network of roots and mycelium.
Below the ground is not the only hidden place full of life. Register for one or more sessions of the “Underneath” series happening at different preserves this summer to learn all about it!
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