Protists

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Protists

• 7th Grade

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Whats a protist?

• Its a eukaryotic (many celled) organism which
  lives in moist or wet environments.
• Some are plant-like and contain chlorophyll
• Some are animal-like and can move.

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How do you classify them?

• They are difficult to classify.
• They are usually grouped based on characteristics
  shared with plants, animals, or fungi.
• We can study the evolution of protists through
  fossils and genetic material.

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Plant-Like Protists

• Are called ALGAE
• All contain chlorophyll
• Chlorophyll is the green stuff that helps them
  make food.

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Diatoms

• Found in fresh and salt water
• Make glasslike boxes which can form fossils

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Dinoflagellates

• Use flagella
• Remember? Those long, thin, whiplike structures
• Helps them move in their saltwater environment.

FLAGELLA
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Euglenoids

• Have characteristics of both plants and animals
• When light is present, they can make their own
  food (they have an eyespot to help them find
  light)
• When there is no light, they can eat bacteria or
  other protists

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Red Algae

• Also called seaweed
• Usually many celled
• Can live at depths of 175 meters
• Contain chlorophyll large amounts of red pigment

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Green Algae

• Contain large amounts of chlorophyll
• Can be one-celled or many-celled
• Some scientists think that plants evolved from
  green algae

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Algae

• Its a source of food for ocean organisms
• Called the grasses of the ocean

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Who cares about algae?

• Algae have an environmental impact
• They produce oxygen through photosynthesis
• Sometimes, if there is too much, you can have an
  algal bloom

Would you want to swim in that??
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What else?

• Some people eat algae
• Algae are also used in many cosmetic and food
  products.

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Brown Algae

• Called kelp
• Is many celled
• Lives in saltwater
• Is an important source of food and shelter for
  aquatic organisms

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Animal-like protists

• Called protozoans
• Classified by how they move

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Ciliates

• Have threadlike structures called cilia that
  extend from their cell membranes.
• A Paramecium has two nuclei. The micronucleus is
  involved in reproduction while the macronucleus
  controls other cell functions.
• Ciliates usually eat bacteria.

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CILIA
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Flagellates

• Move by whipping their long flagella
• Many live in freshwater
• Some are parasites
• Proterospongia grow in cell colonies and have
  structures like sponges.

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FLAGELLA
PROTEROSPONGIA
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Another flagellate called Euglena
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False feet

• Some protozoans move and eat using false feet
• They are called pseudopods
• They look like a blob, and a pseudopod is an
  extension of their cytoplasm (blob stuff)
• One type is an amoeba.

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Amoebas use their pseudopods to trap their food.
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Shelled Protozoans

• Can push a pseudopod through a hole in the shell.
• This one is called Difflugia.

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I CANT MOVE!

• One group of protozoans has no way to move on its
  own.
• These protozoans are parasites in humans and
  other animals.
• Their complex life cycle may have them living
  part of their life in one animal and another part
  in a different animal.

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Leishmania is a relative of trypanosomes which
infects more than 10 million people in tropical
regions. Life cycle goes from the midgut of a
sandfly to a mammal when the sandfly bites the
mammal to get a blood meal.
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What else?

• Protozoans are important food sources for many
  animals.
• Shelled protozoans can become a part of the
  sediment layers geologists can use them as an
  indicator species to help locate petroleum
  reserves.
• Some parasites can cause diseases in humas.

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Funguslike Protists

• Produce spores
• Must consume food
• Many move using pseudopods like the amoeba

Physarum polycephalum is a plasmodial slime
mold. 
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Slime Molds

• Are often found on decaying vegetation in moist,
  cool areas.

IS THAT DOG PUKE???
NOPE. ITS SLIME MOLD.
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Water molds

• Live in wet places
• Downy mildews can weaken or kill plants.