19.1 Diversity of Protists
KEY CONCEPT
Kingdom Protista is the most diverse of all the
kingdoms.
19.1 Diversity of Protists
Protists are difficult to classify.
• Protista is one kingdom in the domain Eukarya.
19.1 Diversity of Protists
– Protista is the kingdom with the greatest variety (the
“junk drawer”) – organisms that are eukaryotes that do
not fit in the other kingdoms are placed here
19.1 Diversity of Protists
There are 3 types of protists:
- animal-like
- plant-like
- fungus-like
19.1 Diversity of Protists
• Animal-like protists (protozoa)
- consume other organisms
- are all unicellular, unlike animals, which are all
multicellular
- there are four main groups:
19.1 Diversity of Protists
1. zooflagellates
– flagella (tail-like structure) help them swim
Paranema
19.1 Diversity of Protists
2. pseudopods
- change shape as they move
- cytoplasm and plasma membrane extend outwards
to help it move & feed (phagocytosis)
Ex: amoeba
19.1 Diversity of Protists
19.1 Diversity of Protists
3. ciliates
– cilia help them swim and capture food
– Ex: paramecium
macronucleus
contractile vacuole
food vacuole
oral groove
micronucleus
cilia
19.1 Diversity of Protists
4. sporozoan
– are immobile
19.1 Diversity of Protists
- animal-like protists can be:
~ harmful – can transmit diseases
• Protists cause some well-known infectious diseases.
Protist
Causes
Transmitted by
19.1 Diversity of Protists
• Plasmodium – causes malaria; is transmitted by
mosquitoes
human liver
sporozoites
liver cells
developed
parasites
red blood
cells
is a sporozoan!
Malaria Infection
19.1 Diversity of Protists
• Trypanosoma
- causes African sleeping
sickness; is transmitted by
tsetse flies
is a zooflagellate!
19.1 Diversity of Protists
• Giardia – causes intestinal
disease; is transmitted by
drinking contaminated
water
is a zooflagellate!
19.1 Diversity of Protists
• Some animal-like protists can also be:
~ helpful - recycle nutrients in the oceans
~ mutualistic - can live inside other organisms
ex: Trichonympha lives
inside the gut of termites
– helps them digest the
cellulose in the wood
they eat
19.1 Diversity of Protists
• Fungus-like protists:
- decompose dead organisms
- recycle nutrients in an environment
- there are two main types of fungus-like protists:
19.1 Diversity of Protists
1. slime molds:
a) plasmodial slime mold - cells migrate together to form
one single mass that has multiple nuclei = a
plasmodia
19.1 Diversity of Protists
b) cellular slime mold – separate cells that live alone
or migrate together to reproduce
19.1 Diversity of Protists
2. water molds:
- feed on decaying matter in water
- plant parasites on land
19.1 Diversity of Protists
• Plant-like protists
19.1 Diversity of Protists
- most are photosynthetic; those that are are called algae
- unlike plants, they can be unicellular or multicellular
colony
daughter colony
19.1 Diversity of Protists
- all contain chlorophyll and accessory pigments to
absorb the greatest amount of sunlight available
19.1 Diversity of Protists
- unicellular plantlike protists:
1. Euglenoids - have one or two flagella
pellicle
contractile
vacuole
nucleus
flagellum
chloroplast
eye spot
19.1 Diversity of Protists
2. Dinoflagellates
– are mostly marine
– may be bioluminescent
(can produce a light)
– can cause red tide which
occur in polluted waters
~ is harmful because it
Dinoflagellates
kills fish and plants
19.1 Diversity of Protists
3. Diatoms
- have glasslike shells made of silica
- shells of dead diatoms are used in toothpaste
19.1 Diversity of Protists
- Multicellular plant-like protists are classified by their pigments.
1. green algae
- contain
chlorophyll a and b
19.1 Diversity of Protists
2. brown algae
- include giant kelp
- found in cool waters
(Pacific)
- contain chlorophyll c
19.1 Diversity of Protists
3. red algae
- found in warm waters near coral reefs
- contain chlorophyll a
19.1 Diversity of Protists
- reproduction:
- all algae can reproduce asexually (fragmentation)
19.1 Diversity of Protists
- some produce sexually through alternation of generation,
which means sometimes sexually and sometimes
asexually
- sexual reproduction can be triggered by environmental
stress
19.1 Diversity of Protists
KEY CONCEPT
Fungi are heterotrophs that absorb their food.
19.1 Diversity of Protists
• Kingdom Fungi:
– are eukaryotes
– are multicellular, except for yeast
– are heterotrophs
– digestion occurs outside of their bodies and then they
absorb it
– cell walls are made of chitin
19.1 Diversity of Protists
Fungi are adapted to absorb their food from the
environment.
• Plants and fungi have different traits.
– Fungal cell walls are made of chitin.
– Plant cell walls are made of cellulose.
– Plants have chlorophyll and photosynthesize.
– Fungi absorb food through hyphae.
19.1 Diversity of Protists
Fungi have three main parts to their structure:
* hyphae - individual fungal filaments
* mycelium - tangled mass of underground hyphae
* fruiting body - mass of hyphae above ground;
produce spores for reproduction
~ spores are powdery and can travel easily
through the air)
19.1 Diversity of Protists
19.1 Diversity of Protists
Fungi come in many shapes and sizes.
1. Primitive fungi are:
- the smallest and simplest group of fungi
- are mostly aquatic
19.1 Diversity of Protists
2. Sac fungi (Ascomycota)
- have a cup-shaped fruiting body (ascus ) where
zygotes form
19.1 Diversity of Protists
- Examples:
- yeasts (single-celled) – used to make bread
- Penicillium
~ used to make medicine (antibiotic)
~ used in Roquefort and blue cheese
19.1 Diversity of Protists
3. Club fungi (Basidiomycota)
* have a basidium = club-shaped fruiting body;
underside has gills that produce spores
* Examples:
- mushrooms
- rust
19.1 Diversity of Protists
gills
fruiting
body
19.1 Diversity of Protists
4. Bread molds (Zygomycota)
* are often found on spoiled food
* have sporangia are at the tip of hyphae that produce
spores
19.1 Diversity of Protists
* have rhizoids - rootlike hyphae that anchor fungus to
bread & take in digested material
19.1 Diversity of Protists
* have stolons – stemlike hyphae that grow on surface
sporangia
spores
rhizoids
19.1 Diversity of Protists
Reproduction
* Sexual
~ unfavorable/harsh conditions
* Asexual
~ favorable conditions
19.1 Diversity of Protists
* single-celled fungi reproduce asexually through budding
19.1 Diversity of Protists
•
All fungi form spores and zygotes.
19.1 Diversity of Protists
Fungi may be 1) decomposers, 2) parasites, 3) mutualists
* In their role as decomposers (helpful to ecosystems):
~ decay organic matter such as dead leaves, twigs,
logs, and animals = Saprobes
~ recycle nutrients in the environment
~ source of food (mushrooms) & medicine (antibiotic)
19.1 Diversity of Protists
• Fungi can act as parasites/pathogens (harmful)
– are parasitic to plants and animals human diseases
include ringworm, athlete’s foot, and jock itch
– spoils food
19.1 Diversity of Protists
• Fungi can act as mutualists.
a) lichens algae and fungus live together on trees or
rocks
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b) mycorrhizae = fungus living on plant roots helps plant
to fix nitrogen