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									Kingdom Protista
20-1
           What is a protist
  • Protist- any organism
    not a plant, animal,
    fungus, or prokaryote
  • All are eukaryotes
    (have a nucleus)
  • Most are unicellular
  • some algae have many
    cells
         Evolution of Protists
• Protista- a Greek        Endosymbiosis

  word meaning the
  first.
• The first Eukaryotes
  on earth were protists
• Hypothesized to
  come from a
  symbiosis of several
  cells
                           Lynn Margulis
     Classification of Protists
• Classified based on the way they obtain
  nutrition:
  – Heterotrops with internal digestion- animal-
    like protists (Protozoa)
  – Heterotrophs with external digestion-
    fungus like protists
  – Autotrophs- plant-like protists (Algae)
    20-2 Animallike Protists: Protozoans

•   Protozoa classified based on movement
•   Zooflagelates- by flagella
•   Sarcodines- by pseudopods
•   Ciliates- by cillia
•   Sporozoans- do not move on their own
Phylum Zoomastigina
          Zooflagelates- animallike
            protists that swim with
            flagella

          Can reproduce
            asexually- by binary
            fission
            or
            sexually- gametes
            produced through meiosis
            (gametes fuse during
            fertilization)
     Phylum Sarcodina
           • Sarcodines- animallike protists
             that move and feed with
             pseudopods

           • Pseudopod- a temporary
             projection of cytoplasm

           • Amoeboid movement-
             movement by pseudopod

           • Eat by surrounding a meal with a
             pseudopod creating a food
             vacuole
Amoeba
           • Food Vacuole- small cavity in the
             cytoplasm that stores food
            Phylum Sarcodina
• Sarcodines reproduce asexually by binary
  fission


  Amoeba binary fission
             Phylum Ciliophora
                   • Ciliates- use cillia for movement
                   • Internal anatomy:
                      – Trichocysts- small bottle
                         shaped structures used for
                         defense. Release stiff
                         projections that protect the
                         cell
                      – Two nucli present:
                          • Macronucleus- contians
                            the main genetic material
                            used every day
Paramecium                • Micronucleus- smaller
                            nuclei that has a reserve
                            copy of the cells genet
             Phylum Ciliophora
                   • Internal anatomy cont.:
                      – Gullet- where food enters the
                        cilliate. Food entering creates
                        food vacuole.
                      – Anal pore- where waste
                        materials leave the cilliate
                      – Contractile vacuole- Cavities
                        in the cytoplasm specialized
                        to collect water and pump
                        water out of the cliilate

Paramecium
             Phylum Ciliophora
                 Reproduce sexually through
                  conjugation

                 Conjugation- an exchange of
                  genetic material




Paramecium
         Phylum Sporozoa
• Sporozoans do not move ad are parasitic
• Plasmodium that causes malaria is an
  example
• Reproduce by sporozytes
    Animallike protists and disease
• Malaria- caused by a Plasmodium sporozoan.
   – Plasmodium infects the liver and red blood cells
   – 300 to 500 million suffer from this and 2 million die annually.
   – Carried by the female Anopheles mosquito

• African sleeping sickness- caused by a Trypanosoma
  zooflagellate
   – Carried by the tsetse fly.
   – Causes chills, rashes, and infects nerve cells.
   – Severe damage to the nervous system causes individuals to loose
     consciousness and fall into a deep fatal sleep

• Amebic dysentary- Severe diarrhea Caused by the
  Entamoeba a sarcodine

• Giardia- Severe diarrhea Caused by the Giardia a
  zooflagelate
  Ecology of Animallike protists
• Some live symbiotically with other
  organisms
  – Ex. Trichonympha live in the digestive system
    of termites and allows them to digest wood
• Some recycle nutrients
     Plantlike Protists (Algae)
Seven major phyla of algae
• Tour phyla contain unicellular organisms
  – euglenophytes
  – dinoflagellates
  – chrysophytes
  – diatoms
• Three phyla include multicellular
  organisms
  – red algae
  – brown algae
  – green algae
• Algae classified based on photosynthetic
  pigments they contain

• This is an adaptation to conditions of limited light

• Each form of chlorophyll—chlorophyll a,
  chlorophyll b, and chlorophyll c—absorbs
  different wavelengths of light.
• The result of this evolution is that algae can use
  more of the energy of sunlight than just the red
  and violet wavelengths.
20–3 Plantlike Protists: Unicellular Algae
• Plantlike protists are called algae

• Contain the green pigment
  chlorophyll and carry out
  photosynthesis

• Many also have accessory
  pigments- pigments other than         Euglena
  chlorophyll that absorb light

• Many unicellular ones can move
 Plantlike protists (unicellular algae)

• Types of plantlike unicellular protists
   –   Euglenophytes
   –   Dinoflagellates
   –   Chrysophytes
   –   Diatoms
            phylum Euglenophyta
• Euglenophytes
   – plantlike protists- have chloroplasts
   – have two flagella- for movement
   – no cell wall.
   – reproduce asexually by binary fission
• Interesting features
   – Eyespot- group of cells that can detect changes in the
     amount of light in the environment
   – Pellicle- cell membrane in euglenas
Euglena
         Phylum Pyrrophyta
• Dinoflagelates
• some photosynthetic and
  some are heterotrophs
• Reproduction: most
  asexually by binary
  fission
• Many are luminescent
  when agitated
• pyrrophyta- means “fire
  plants”
       Phylum Chrysophyta
• Chrysophytes
• Yellow-green and
  golden-brown algae
• Chysophyta- means
  “golden plants”
• Reproduce sexually and
  asexually
      Phylum Bacillariophyta
• Diatoms
• Produce cells walls
  of rich silicon- the
  main ingredient in
  glass
• Reproduce sexually
  and asexually
• Used in things like
  toothpaste and other
  grainy products
        Ecology of Unicellular Algae
                                        Algae Bloom
• Plantlike protists make up
  much of the phytoplankton.
   – Phytoplankton- small
     photosynthetic organisms at the
     surface of oceans
      • The producers in aquatic food
        chains

• Algae blooms- rapid growing
  of algae where nutrients are
  rich.
   – Usually around sewage
                                          Red Tide
     discharge.
   – Most nontoxic but deprive water
     of nutrients killing organisms

• Red tides are toxic algae
  blooms of Gonyaulax and
  Gymnodinium
 Plantlike Protists: Red, Brown, and
             Green Algae
• Largely multicellular algae
• Sea weeds
• Autotrophs
  – Named based on their
    photosynthetic pigments
• Similar reproductive cycles
  to plants
  – Mostly sexual reproduction
        Phylum Rhodophyta
• Red Algae
• Contain
  – Chlorophyll a
  – Phycobilins- a red accessory pigment
• Example: Chondrus crispus
        Phylum Phaeophyta
• Brown Algae
• Giant kelp is the largest- can grow more
  than 60 meters
          Phylum Chlorophyta
•   Green Algae
•   Can be unicellular
•   Colonial
•   Or multicellular




                     Green Algae
            Volvox
                                   Ulva
     Characteristics of Fungi-like
               protists
• Like Fungi:
  – Absorb food of dead/decaying organisms
  – Look like fungi


• Unlike Fungi:
  – Lack chitin in cell walls
  – Have centrioles
   3 Broad Groups of Fungi – Like
              Protists
*Cellular Slime Molds- phylum Acrasiomycota
  --Found in damp, organic soils
  --Play key role in recycling matter
  --Distinct cell membranes during all life stages
*Acellular Slime Molds- phylum Myxomycota
  --Enter stage where many cells fuse to form one large
      cell with many nuclei – can’t tell where one starts
      and another begins
*Water molds- phylum Oomycetes
   --Thrive on dead or decaying matter in water or can be
     plant parasites on land in times of heavy rainfall
Acellular Slime Mold
Water Mold
  Ecology of Fungi Like Protists
• Slime molds and water molds are MOST important
  recyclers of organic material

• Some can be harmful
   – Plant diseases ex. Irish Potato Famine – water mold
              Phytophtora infestans
      *overgrowth of water mold caused by wet and cool
              conditions

• Why is the earth not littered with dead orgs?
   – Tissues broken down by Fungi Like Protists and other
              decomposers

								
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