--fungi can be decomposers, parasites, or mutualists (benefits the host also: fungi gives nitrogen and phosphorus in
exchange for photosynthetic products/sugars)
Why do biologists study fungi?
Fungi feed land plants
-fungi that live in close association to plant roots
Without these fungi, plants
grow much slower
Fungi speed the Carbon Cycle on land
Lack of fungi: Carboniferous period has few
—fungi that live by digesting
dead plants—and coal was formed because of the buildup of dead plants.
absent because the present coal-forming-swamps were too acidic.
Abundance of fungi: The end of the Permian period had a mass extinction. During that
time, fungi numbers spiked because there was so much dead matter/food for them.
Fixation of carbon by land plants—carbon in atmospheric CO
is converted to cellulose,
lignin, etc and stored in plants.
Fungi digest lignin and cellulose so the carbon can be recycled into glucose and CO
feed others so they can perform cell respiration. (They make the cycle turn rapidly if
fungi were absent, carbon would be trapped in plants and the cycle would be slow).
Release of CO
from plants, animals, fungi due to cellular respiration—the oxidation of
glucose and ATP production.
Fungi’s economic impacts
Fungi are generally more helpful than harmful and affect many species
Harmful: Parasitic fungi in humans—athlete’s foot, ringworm, etc. But, only a few
fungi species make humans sick, compared to bacteria.
Helpful: Antibiotics for bacterial infection
Harmful: infects crops
Wheat, corn, barley, and other grain crops infected by fungi called rusts, smuts,
Saprophytic fungi spoil crops, esp. fruit and veggies.
Helpful: Fungi needed to make bread, soy sauce, cheese, beer, etc. and fungal enzymes
used to make some foods better.
Chestnut and elm species important from elsewhere had fungi species on it. These fungi
infected local elm and chestnut that had no resistance to it, so they all died.
How do biologists study fungi?—morphology, phylogeny
Millions of fungal species. Many are undiscovered
Fungi only have 2 growth forms:
small and easy to manipulate, so used in labs a model organisms
—multicellular, filamentous structures
most fungi are this type, so used for morphological studies
Fungal mycelium traits
Can grow really big if it has nutrients. It is one of the oldest and biggest living things.