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Protists and Fungi
Chapter 19
•Kingdom Protista
– Most diverse of all the kingdoms because its organisms are different from
one another. Difficult to classify because some protists are not closely
related.
– Nicknamed the “odds and ends” kingdom
– It is predicted that Protista classification will change as scientists find out
more about the molecular evidence of these mysterious organisms.
– Most unicellular, some multicellular
– Some autotrophs, some heterotrophs
– Cell walls of cellulose
– Protists are eukaryotes that are not animals, plants, or fungi, but Protists can
be animal-like, plantlike, or funguslike.
Animal-like protists consume other
organisms and can move.
• Heterotrophs
• Single-celled
• Animal-like protists are often called
protozoa.
• Move in various ways:
—Cilia help protists swim and capture
food
—Flagella help zooflagellates swim
—Pseudopod (“False Foot”) changes
shape as they move
Some animal-like protists cause wellknown infectious diseases.
•
Malaria is caused by Plasmodium and
spread by mosquitoes.
•
Review: Why does sickle cell anemia
play an advantage to those in third
world countries?
Plantlike protists are photosynthetic and are called algae.
– single-celled, colonial, or multicellular
– no roots, stems, or leaves
– 3 types of algae: Green, Red, and
Brown
Euglenoids are a large group of plantlike protists
–mostly photosynthetic
– some heterotrophic
– single-celled
– one or two flagella
Dinoflagellates are mostly marine
plantlike protists.
–can cause red tide, which
is toxic and causes fish kill.
Diatoms are plantlike protists with glasslike shells.
–shells made of silica. Used in toothpaste to help polish teeth.
–Provides Earth with oxygen.
Dinoflagellates
• Some algae produce sexually and asexually.
– Some species
alternate generations, which means they can do
both types of reproduction.
–Sexual reproduction can be triggered by environmental stress.
Funguslike protists decompose dead
organisms and organic matter.
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heterotrophs that absorb their food
can move like animals, whereas fungi (mushrooms) cannot
can be parasites of plants or fish
Examples:
– Slime mold that grows on trees and on forest floor. It can ooze its way around.
– Water molds are freshwater, funguslike protists. One type of water mold caused
The Great Potato Famine of Ireland in the 1800’s
•Kingdom Fungi
– Fungi are multicellular organisms, with
the exception of yeasts.
– Eukaryotes
– Heterotrophs because absorb their food
from the environment through hyphae
– Cell walls of chitin
– decomposers and pathogens
•
Fungi and bacteria are the main
decomposers in any ecosystem.
– decompose dead leaves, twigs, logs,
and animals
– return nutrients to the soil
– can damage fruit trees and wooden
structures
•Fungi can act as pathogens.
–human diseases include ringworm and athlete’s foot
– plant diseases include Dutch elm disease
• Fungi can act as mutualists. They can form beneficial
relationships with other organisms.
– Examples:
– Lichens: Algae feed fungus through photosynthesis, and fungal
mycelium provides habitat for algae. Can grow anywhere because
they are highly adaptive.
– Mycorrhizae: Hyphae of fungus colonize plant roots to boost plant
growth by absorbing nutrients. Plants give fungus sugar from
photosynthesis.
– Fungal gardens and insects: Leafcutter ants carry leaves back to nests
to provide food for fungi. The ants eat the growing fungi mycelium.