Protists

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Protists
Diatoms make up part of the diverse group of
protists
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What is a Protist?

• Classified in Kingdom Protista
• Protista means very first
• Loosely related group of micro orgs.
• Believed to evolved 1.5 million years ago
• Symbiosis of bacteria?
• Ex Mitochondria and Chloroplasts
• Why is this name fitting?
• Protists are the simplest Eukaryotes
• Nucleus and Membrane Bound Organelles
• Evolutionarily could have been ancestor
  eukaryote organism

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Endosymbiosis Evolution from Bacteria
Proposed by Lynn Marguilis endosymbiosis/Gaia
Theory Proof separate DNA and extra membranes
around mitochondra and Chloroplasts
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Examples of Protists
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Classification
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What is a Protist? Cont.

• Unicellular, Colonial, or Multicellular
• NOT a plant, animal or fungi

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Classification

• Kingdom Protista All Protists
• Problem to classify because of diversity
• Classified further by mode of nutrition
• Animal Like Protists - Heterotrophic
• Must EAT their food
• Move around like animals
• Plant Like Protists - Autotrophic
• MAKE their own food
• 3. Fungal Like Protists Decomposers/Parasites
• ABSORB their food externally.

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Animal-Like Protists

• Once called Protozoans First Animals
• Make up 70 Percent of all Human Parasites
• 4 Types of Animal-Like Protists
• Based on how they move
• 1. Zooflagellates use flagella to move
• 2. Sarcodines move by extension in cytoplasm
• Called pseudopodia (false feet)
• 3. Ciliates use cilia to move
• 4. Sporozoans do not move at all

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Zooflagellates(Phylum Zoomastigina)

• Swim using flagella
• Whiplike tails
• Eat food through cell membranes
• Ex Trypanosoma African Sleeping Sickness
• Parasitic or free living
• Can use asexual and sexual life cycles

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2. Sarcodines(Phylum Sarcodina)

• Obtain food and moves by projections of cytoplasm
  called pseudopods
• Ameoboid movement streaming movement of
  cytoplasmic projections
• Contractile Vacuole controls water in cell
• Food vacuole holds food
• Ex Ameobas
• Ex Entameoba causes amebic dysentery

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Sarcodine AnatomyEx Ameoba
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3. Ciliate(Phylum Ciliophora)

• Use cilia to move and obtain food
• Very organized anatomy
• 2 nuclei macronuclei and micronuclei
• Oral Groove mouth-like structure
• Gullet stomach like structure
• Anal pore waste release
• Contractile vacuole store, pump water
• Pellicle rigid protein cover, anchors flagella,
  cilia
• Trichocysts projections that protect the cell
• Ex Paramecium

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Cilliate AnatomyParamecium
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Conjugation in Ciliates

• Typically use Asexual Binary Fission
• If stressed can use Conjugation
• Sexual recombination of genes
• NOT Reproduction (No NEW individuals)
• Actually produces clones!!! Why?
• Meiosis of one micro nucleus in each org
• Two orgs swap new micronuclei
• Macro nuclei dissolve and micro becomes
  macronuclei
• New Macronucleus is part self and part other org
  in both

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4. Sporozoans(Phylum Sporozoa)

• Cannot move on their own
• Obligate parasites
• Complex life cycles that involve many hosts
• Reproduce using sporozites
• Ex Plasmodium, Causes Malaria

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Ecology of Animal Like Protists

• Not so Good Can be parasitic/cause disease
• Malaria, African Sleeping Sickness,
  Cryptosporidium
• Good Symbiosis
• Termites have beneficial animal like protist
  called Trichonympha in their stomachs
• Break down cellulose in wood so termites can use
  it as food