Protist and Fungi
Adaptations
Bio.2.1.2 Analyze the survival and reproductive success of organisms in
terms of behavioral, structural, and reproductive adaptations.
Protists
• Protists are unicellular or simple
multicellular eukaryotic
organisms that are not plants,
fungi, or animals.
• Protists are classified by the
characteristics that make them
fungus-like, plant-like, or animallike.
Protist Structural Adaptations - Nutrition
• Many protists are autotrophs,
organisms that make their own
food.
• Other protists are heterotrophs,
organisms that must get their
food by eating other organisms
or their byproducts.
Protist Structural Adaptations - Motility
• Protists use flagella, cilia, or
pseudopodia for locomotion.
• Flagella are long whip like cell
extensions.
• Cilia are short, hairlike,
cytoplasmic projections that line
the cell membrane.
• Pseudopodia are large, rounded,
cytoplasmic extensions used for
movement and feeding.
Protist Behavioral Adaptations
• Taxis – movement towards or
away from a stimulus
• Phototaxis – moving towards or
away from light
• Chemotaxis – moving towards a
chemical, such as food, or away
from a chemical, such as a poison
Protist Reproductive Adaptations
• Protists reproduce either asexually, sexually, or both.
• They reproduce asexually by binary fission or multiple
fission.
• The advantage of asexual reproduction is they don’t need a
mate.
• The disadvantage is you don’t get variety in the offspring.
• They often reproduce sexually by conjugation.
Protists that impact humans
• Red tides produce harmful toxins that kill organisms
living in the surrounding water.
• Algal blooms reduce the oxygen content of water,
killing the organisms in the area.
• We eat seaweed and use it to make agar (and jelly).
• Protists cause malaria (kills 3 million annually),
giardiasis (backpackers diarrhea), and
cryptosporidiosis (more diarrhea).
Fungi
• Fungi are eukaryotic,
nonphotosynthetic
organisms that can
be unicellular or
multicellular in form.
Fungi Structural Adaptations - Nutrition
• Fungi are among the most
important decomposers of
organic matter.
• Fungi obtain nutrients by
secreting enzymes and
absorbing simple organic
molecules from their
environment.
• This makes them saprotrophs.
Fungi Structural Adaptations
• Fungi are made up of short
filaments called hyphae.
• Mats of hyphae are called
mycelium.
• Fungal cell walls contain
chitin rather than cellulose,
which is found in plant cell
walls.
Fungi Reproductive Adaptations
• Most fungi reproduce both asexually and
sexually.
• Asexual Reproduction
• Asexually, fungi produce thousands of
genetically identical haploid spores.
• When these spores are placed in favorable
environmental conditions, they germinate
and grow new hyphae, each of which can
form a mycelium and produce thousands of
new asexual spores.
Fungi Reproductive Adaptations
Sexual Reproduction
• Fungi occur in mating types that are
sometimes called minus and plus.
• When two different mating types of the
same species encounter one another, the
hyphae of one mating type fuse with the
hyphae of the opposite mating type.
• These fused hyphae give rise to a specialized
structure, which produces and scatters
genetically diverse spores.
Fungi and Plants
• Mycorrhizae are symbiotic structures
that form between plant roots and a
fungus.
• The fungus provides certain ions and other
nutrients to the plant and, in turn, the
fungus gets sugars from the plant.
• Lichens represent symbiotic
relationships between fungi and
photosynthetic organisms, such as
cyanobacteria or green algae.
Fungi and Humans
• Common fungal infections include ringworm,
athlete’s foot, and yeast infection.
• Fungi are used in the production of cortisone,
penicillin and other antibiotics, and some
genetically engineered drugs.
• Fungi are used in the production of familiar
foods such as cheeses, bread, beer, wines,
and soy products.