What is a fungus?

• Fungi were once considered members of the Kingdom Plantae.

• Further study however shows that fungi are more closely related to animals than they are plants.

• They now have their own kingdom.

How do you define a fungus?

• A fungus is a heterotrophic, eukaryotic organism.

• Most fungi are multi-cellular, but there is a very important type which is uni-cellular.

• Fungi (plural form) exhibit both sexual and asexual reproduction based on the species.

Fungi nutrition

• Most types of fungus are decomposers. • Fungi are the principal decomposers in

every ecosystem, capable of breaking down the toughest organic substances.

• Some fungi are parasitic. You may have been a host to a fungus at one time or another.

• Athlete’s foot is a fungus, so is ring worm.

• Some types of fungi live symbiotically with other organisms.

Fungi symbiosis

• Mycorrhizal fungi are found in the soil around tree roots. They help supply the tree with phosphorous and nitrogen while getting carbohydrates from the tree in return.

• A lichen is a symbiotic organism consisting of an algae and a fungi.

Fungal cell structure

• Fungi lack chloroplasts and are unable to photosynthesize, but they do have a cell wall.

• Their cell walls are not made of cellulose, like those of a plant, but chitin.

• Chitin is also found in the exoskeleton on insects.

Spores• Fungi reproduce asexually by means of

spores.• Spores are similar to seeds, but contain fewer

nutrients.• Spores are designed stay dormant for a long

period of time before developing.• They are able to withstand unfavorable

conditions, and then become active when conditions change.

• Some bacteria, plants and algae also produce spores.

Spore shapes

So, what good are fungi?

Kingdom Fungi

• More than just More than just mushroomsmushrooms

• Food! There are thousands of edible mushroom species.

• They are low in fat and provide many important minerals.

• Only 3% of mushrooms in the world are safe to eat.

Enjoy, but beware…

• Many species of mushroom are extremely toxic to humans.

• Symptoms of mushroom poisoning include abdominal pain, vomiting and swelling.

• Hundreds of people die from eating wild mushrooms though with prompt medical care most recover.

Deadly galerina

Two billion dollar industries

• Rely on the biological processes of a unicellular fungi.

• Baker’s yeast is an important ingredient in bread and other baked goods.

• Brewer’s yeast is used in the production alcoholic beverages.

Other members of the kingdom fungi.

• Molds are fungi. Several types can be dangerous to humans, such as black mold.

• Truffles. A delicacy from France.

Review

• Fungi are heterotrophic. True or False?• Fungi are eukaryotic. True or False?• Fungi have cell walls. True of False?• Name some roles fungi play in the

environment.• What are spores?• Should you eat wild mushrooms?• What two industries rely of fungi?• Are there any unicellular fungi?