Protists vs. Fungi: Key Differences, Examples & Roles in Ecosystem
Protists are a grab-bag kingdom of mostly single-celled organisms with a nucleus—algae, amoebas, slime molds—while fungi are a separate kingdom of multicellular (except yeasts) organisms that build cell walls from chitin and absorb food externally.
People often lump “fungi-like” slime molds with mushrooms because both sprout spore structures, yet slime molds are actually protists hunting bacteria on your garden mulch—leading hikers and students to mislabel them in field guides and classroom labs alike.
Key Differences
Protists run on flagella, cilia, or pseudopods; fungi grow filamentous hyphae and reproduce via spores. Protists photosynthesize, engulf, or absorb; fungi only absorb dissolved nutrients. Their cell walls differ—cellulose vs. chitin—placing them in entirely different evolutionary branches.
Examples and Daily Life
Bread mold (Rhizopus), portobello mushrooms, and antibiotic-producing Penicillium are fungi. Seaweed in miso soup (brown algae), pond scum (Euglena), and the malaria agent Plasmodium are protists. Each silently powers ecosystems: fungi recycle forest litter, while protists feed aquatic food webs and produce half of Earth’s oxygen.
Can a slime mold be both?
No—slime molds are protists despite their fungus-like fruiting bodies; true fungi never have amoeboid feeding stages.
Why do antibiotics target fungi but not protists?
Antibiotics like penicillin hit fungal-specific chitin walls and enzymes; protists lack these, so antiparasitics instead disrupt their unique cell membranes or metabolism.
Which kingdom causes athlete’s foot?
Fungi—specifically dermatophytes such as Trichophyton—thrive on keratin in skin and nails, not protists.