The Protists

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The Protists
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What are Protists?

• Name means the very first
• Most are single-celled, but some are composed of
  hundreds of cells (colonies).
• 200,000 or more species
• Many are producers, liberating oxygen
• Some are decomposers
• Some are causes of disease
• They are eukaryotes unlike the blue-green algae
  and bacteria.

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Protist Phyla

• Chlorophyta Sarcodina
• Rhodophyta Zoomastigina
• Chrysophyta Sporozoa
• Pyrrophyta Ciliophora
• Euglenophyta Myxomycota
• Phaeophyta Oomycota Acrasiomycota

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Euglenophyta

• Named after the euglena.
• Mostly fresh water (aquatic)
• They possess chloroplasts and an eyespot.
• They have a pellicle, not a cell wall.
• They can absorb small food particles through
  their pellicle when light is not available.
• Euglenoid movement is used when water is
  insufficient.
• Reproduction is by binary fission.

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The euglena

• The typical euglena has two flagella one is
  longer than the other and pulls the organism
  through the water.

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Sarcodina

• Have pseudopodia (false feet) they use them for
  movement and feeding.
• The ameba is the best known the name means to
  change.
• Amebas feed by engulfing their prey.
• Foraminifera are also in this group they produce
  calcium carbonate shells.
• Heliozoans produce silica shells.

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The Ameba
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Forams - Planktonic
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Forams - Benthic
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The Heliozoans
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Zoomastigina

• Flagellates
• Some are saprophytes some are parasites.
• Trychonympha lives in the termites digestive
  tract it breaks down cellulose.
• Trypanosomes cause African Sleeping Sickness in
  humans.

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Trypanosomes
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Trichonympha
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Sporozoans

• Do not have structures for movement
• All are parasites
• They produce spores.
• They live in multiple hosts to complete their
  life cycles.
• Malaria is caused by Plasmodium.

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Plasmodium
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Ciliophora

• They have cilia for propulsion.
• They are very complex for one cell.
• Paramecia are the best known examples.
• They have macro and micro nuclei.
• They reproduce by cell fission or by conjugation.
  Micronuclei are exchanged in this sexual process.

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Paramecia
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Ciliates
Didinium
Strobilidium
Spirostomum
Chondylostoma
Coleps
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Pyrrophyta

• The dinoflagellates the fire plants
• Most are photosynthetic but some are
  heterotrophs.
• Most are marine but some are aquatic.
• If disturbed they may phosphoresce.

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Pyrrophyta fire algae
Ceratium
Peridinium
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Fire algae
Gymnodinium
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Chrysophyta

• They are the golden plants.
• This phylum includes yellow-green and golden
  algae as well as diatoms.
• Their cell walls contain pectin rather than
  cellulose.
• Diatoms are the most abundant member of this
  phylum. They produce silica shells that are made
  of two halves resembling a Petrie dish.

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Chrysophyta - Diatoms
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Chlorophyta

• The green algae
• Most are aquatic.
• Their cell walls contain cellulose.
• They have chloroplasts with chlorophylls a b
  the storage product is starch.
• They are unicellular, filamentous and some form
  leaf-like sheets.

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Green algae
Micrasterias
Spirogyra
Ulva
Oedogonium
Closterium
Volvox
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Green algae - Desmids
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Phaeophyta

• These are the brown algae dusky plants.
• Principle pigments include chlorophyll,
  carotenoids, xanthophylls fucoxanthinins.
• All are multicellular and form kelps such as
  Fucus (rockweed).

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Brown algae
Macrocystis
Fucus
Ectocarpus
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Rhodophyta

• The red algae they possess phycoerythrin.
• Red algae also can be green, purple, and reddish-
  black.
• These are deep, cold water algae and are much
  shorter than the brown algae.

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Red algae
Polysiphonia
Batrachospermum
Chondrus
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Acrasiomycota

• Cellular slime molds
• Begin their life cycles as ameba-like organisms.
• It sends out signals to other cells to mass
  together. The mass migrates for several cm. then
  forms a fruiting body which produces spores.

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Cellular slime molds
Dictyostelium
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Myxomycota

• Acellular slime molds
• A single cell with thousands of nuclei
• Move and eat organic matter then they form a
  fruiting body and produce spores. They then form
  cells that are flagellated and which fuse to form
  ameba-like cells to begin the cycle again.

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Acellular slime molds
Physarum
Trichia
Dydimium
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Oomycota

• The water molds and downy mildews
• Thrive on dead and decaying matter
• Their cell walls are made of chitin.
• Their spores swim rapidly.
• Most live in water but some are parasites of some
  crops like grapes, avocados and potatoes.

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Water molds downy mildews
Saprolegnia
Plasmopara grape mildew