Bacteria
Characteristics:
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prokaryotic
unicellular
usually have locomotion
reproduction:
o sexually – conjugation (2 bacteria exchange DNA)
o asexually – binary fission (most common) – splits in two
• nutrition: autotrophic or heterotrophic
• respiration: aerobic or anaerobic
Classification:
 Kingdom Archaebacteria – “ancient bacteria”
o able to live in extreme environments (thick mud, hot springs, salty environments)
 Kingdom Eubacteria – “true bacteria”
o many are pathogenic (disease causing)
-ex: E. coli
Importance:
• Beneficial:
o decomposers
o produce antibiotics
o break down sewer waste
o used in research
o used in food making (ex: yogurt)
o form symbiotic relationships with humans (E. coli in intestine)
o nitrogen fixation
• Harmful:
o cause disease in humans, livestock, and crops
Protists
Characteristics:
• eukaryotic
• mostly unicellular
• may be plant-like, animal-like, or fungus-like in mode of nutrition (how they get food)
Animal-Like Protists:
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known as protozoans – “first animals”
heterotrophic
classified by locomotive structures (how they move)
Examples: Amoeba, Paramecium, Plasmodium (causes malaria), Trypanosoma (causes African sleeping sickness)
Plant-Like Protists:
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known as algae
autotrophic by photosynthesis
contain chlorophyll
Examples: diatoms, dinoflagellates (cause red tide), kelp
Fungus-Like Protists:
• heterotrophic
• decomposers
• absorb food
• Examples: Physarum (plasmodial slime molds), Dictyostelium (cellular slime molds)
Importance:
• Beneficial:
o decomposers
o major food source in aquatic food chains
o used as abrasives in toothpaste
o food source
o used in many foods
• Harmful:
o cause disease (malaria, African sleeping
sickness)
o cause red tide
o kill crops
Fungi
Characteristics:
• eukaryotic
• multicellular (except yeasts)
• heterotrophic by absorption
o contain hyphae – rootlike structures for absorbing nutrients
• reproduce sexually & asexually
• no locomotion
• cell walls made of chitin
• decomposers
Examples:
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Rhizopus (black bread mold)
Yeast
Mushrooms, puffballs
Cup fungus
Importance:
• Beneficial:
o make antibiotics (penicillin)
o used in cheese-making (bleu cheese)
o used in baking industry (yeast)
o used in alcohol industry (yeast)
o used as a food source
o decomposers
• Harmful:
o cause disease in humans and in crops
o cause allergies
o spoil food
• Ringworm fungus
• Athlete’s foot fungus
• Truffles, morels