A. MUSHROOMS: PARTNERS AND RECYCLERS
Mushrooms do more than make a good pizza topping! Some glow in the dark; some are deadly poisonous. Some turn blue when you cut them; some smell like dead animals. Some are star-shaped; some are flat. Some provide nutrients for plants while other mushrooms are parasitic and take nutrients from plants. Not all mushrooms are decomposers, but almost all mushrooms are habitat for other organisms.
The best time to find mushrooms is just after a rainy spell during warm weather. In Florida, you're guaranteed to see mushrooms almost anytime!
Some mushrooms can be deadly if eaten. However, this is not a good reason to avoid studying them. Make sure your students wash their hands after handling mushrooms and keep all wild mushrooms away from their mouths!
Mushrooms aren't plants or animals, but have their own classification-the Kingdom Fungi. Because they lack chlorophyll (the green pigment that absorbs energy from sunlight and uses it to make food), mushrooms get the food energy they need in other ways. Some kinds of mushrooms break down dead animal and plant matter for nourishment while other mushrooms absorb nutrients from living plants.
We usually see only a small fraction of a mushroom's body. The part we see is the reproductive part, like a seed-containing fruit on a tree. The rest of the mushroom's body is made up of hundreds of tiny, branching threads. The individual threads, or hyphae (pronounced HI-fee), grow at an incredible rate. As the hyphae branch, the threads form a network called the mycelium (pronounced my-SEEL-ee-um). The densely branched mycelium spreads out through the sand or dead matter and the hyphae absorb needed nutrients. If the hyphae cross each other and fuse together, small buttons are created that can become fruiting bodies almost overnight. For most of the year, a mushroom remains completely underground. After a good rain, the mycelium enlarges rapidly and will send up fruiting bodies with spores.
Spores are almost weightless and can float long distances on a light breeze. But not all spores travel with the wind. Flies, attracted to mushrooms that smell like rotten meat, carry spores to a variety of locations. Animals such as flying squirrels and the Florida mouse will eat mushrooms and the spores will pass, unharmed, through their digestive tracts. Spores can also travel in water.
Some mushrooms have a cooperative, mutually beneficial relationship with tree roots. This relationship is called mycorrhizal symbiosis (pronounced MY-ko-RY-zal SIM-by-O-sis). The hyphae attach themselves to the roots and absorb sugars and amino acids stored by the tree. The tree roots, with the help of the attached hyphae, are able to absorb more water and minerals, such as phosphorus and nitrogen. Approximately 2/3 of plant species in the world have a fungus association. This cooperative relationship is essential for plants in the Florida scrub. Without it, many plants could not survive in the nutrient poor sand.
Mushrooms that are mycorrhizal are not decomposers. Mycorrhizal mushrooms seem to pop up out of the ground. If a mushroom is a decomposer, you will normally see it attached to a dead tree or on rotting leaves. The decomposer mushroom stretches thin filaments throughout the decaying material and sends out a chemical that helps break the soft wood into nutrients. The decomposing mushroom plays an important role in any habitat by helping to keep dead matter from accumulating. Without decomposers, the world would be overwhelmed by a sea of waste!
Mushrooms are food for many kinds of animals and insects. Over time, some species of mushroom have developed poisons that protect them from being eaten. Their poisons are mostly effective against eager vertebrates, such as mice, gray squirrels, and flying squirrels, but some poisons may also protect a mushroom from snacking insects. If the mushroom is mycorrhizal, the poisons do not affect the associated tree.
|III.A.1-Part 1 Part 2 mushroom
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III. LIFE IN THE LEAF LITTER LAYER
A. Mushrooms: III.A.1 III.A.2 III.A.3
B. Life in a Microhabitat III.B.1
C. Glossary D. Questions for Student Evaluation