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66.39.52.159glarsonProtists_2009.ppt

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									Protists

 KEY CONCEPT
   Kingdom Protista is the most diverse of all the
   kingdoms.
Protists

Protists can be animal-like, plantlike, or funguslike.
 • Protists are eukaryotes that are not animals, plants, or
   fungi.
Protists

• Animal-like protists consume other organisms.
   – heterotrophs
   – single-celled
Protists

 • Plantlike protists are photosynthetic.
     – single-celled, colonial, or multicellular
     – no roots, stems, or leaves
Protists

 • Funguslike protists decompose dead organisms.
    – heterotrophs
    – can move, whereas fungi cannot
Protists

Protists are difficult to classify.

• Protista is one kingdom in the domain Eukarya.
Protists

 • Protist classification will likely change.
    – Some protists are not closely related.
    – Molecular evidence supports reclassification.
Protists

 KEY CONCEPT
   Animal-like protists are single-celled heterotrophs
   that can move.
Protists

Animal-like protists move in various ways.
• Animal-like protists are often called protozoa.

                                                         macronucleus


                                                             contractile vacuole
                         food vacuole


                               oral groove
                                        micronucleus

                                                 cilia
Protists

 • Protozoa with flagella are zooflagellates.
     – flagella help zooflagellates swim
     – more than 2000 zooflagellates
Protists

 • Some protists move with pseudopods.
    – change shape as they move
    – amoebas
Protists

 • Some protists move with pseudopods.
    – change shape as they move
    – amoebas
    – foraminifera
Protists

 • Some protozoa move with cilia.
    – cilia help protists swim and capture food
    – more than 8000 ciliates

                                                   macronucleus


                                                       contractile vacuole
                   food vacuole


                         oral groove
                                  micronucleus

                                           cilia
Protists

   Paramecia have contractile vacuoles to expel excess
   water.
   To avoid an obstacle, they back up, and move away in
   an avoidance reaction.
Protists
Some ciliates remain attached to a surface.
Stentor is an example.
Protists

Some animal-like protists cause disease.
• Protists cause some well-
                                  human liver             sporozoites
  known infectious diseases.
• Malaria is caused by
  Plasmodium and spread by                                     liver cells

  mosquitoes.
• Sleeping sickness is caused
  by Trypanosoma and spread
                                                               developed
  by flies.                                                    parasites

• A giardia infection is caused                         red blood
                                                        cells
  by Giardia and spread
  through water.
                                           Malaria Infection
Protists

Trypanosoma
Protists

Giardia
Protists

Trichonympha lives with termites, digests wood.
• Both species benefit, so this is called mutualism.
Protists
Algae are plantlike protists.
Plantlike protists can be single-celled or multicellular.

 • Photosynthetic plantlike protists are called algae.




                                           colony




                                  daughter colony
Protists

Volvox daughter colonies leaving the mother colony.
Protists

 • Euglenoids are a large group of plantlike protists.
    – mostly photosynthetic
    – some heterotrophic
    – single-celled
                           pellicle
    – one or two flagella                      contractile
                                               vacuole
                                   nucleus                       flagellum




                                        chloroplast


                                                      eye spot
Protists
 • Euglena moves toward the light, which is known as a
   positive phototropism.
 • Has a red eyespot, which is light sensitive
Protists

 • Dinoflagellates are mostly marine plantlike protists.
    – have two flagella
    – may be bioluminescent
    – have stiff protective plates
    – can cause red tide


                                 Dinoflagellates
Protists
  Noctiluca scintillans
Protists

 • Diatoms are plantlike protists with glasslike shells.
    – shells made of silica
    – produce large amounts of oxygen
Protists

More diatoms
Protists

 • Multicellular algae are classified by their pigments.
     – Green algae contain
       chlorophyll a and b.
     – Brown algae contain
       chlorophyll c.
     – Red algae contain
       chlorophyll a and
       phycoerythrin.
Protists
Red algae is used to make agar, food thickener, and
medicine capsules.
Protists

Spirogyra : a type of green algae
Protists

 Slime molds and water molds are funguslike protists.
• Slime molds have both funguslike and animal-like traits.
    – decomposers, like fungi
    – can move, like animals
Protists

 • Slime molds can be plasmodial or cellular.
   – Plasmodial slime molds are giant cells with many nuclei.
   – Cellular slime molds contain independent cells.
Protists

 • Water molds are freshwater, funguslike protists.
    – one type of water mold caused Great Potato Famine
      of Ireland in the 1800’s
    – made of branching
      strands of cells
    – can be parasites of
      plants or fish

								
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