Kingdom Protista (2)

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Kingdom Protista (2)

• Biology 11
• Mr. McCallum

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REVIEW TIME
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Animal-like Protists (Protozoa)

• Heterotrophs
• Must consume to gain nutrition
• Holozoic
• Engulf their food
• Saprozoic
• Absorb pre-digested or soluble nutrients through
  membrane
• 4 phyla
• Sarcodina
• Mastigiphora
• Ciliophora
• Sporozoa

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Animal-like Protists (2)

• Larger population numbers, and larger number of
  species overall than bacteria
• Occupy a diverse range of moist habitats
• Huge range/variability in size (micrometers to
  centimeters)
• Small red blood cell can contain a dozen
• Usually undergo asexual reproduction
• Binary fission
• Can form cysts (hard protective covering over
  cell membrane resting/dormant cells)

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Classification

• Distinguished by their modes of locomotion
• Cilia, flagella, pseudopodia, etc.
• Also
• Types of organelles
• Life cycle
• Mode of reproduction
• Free-living or parasitic

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1. Phylum Sarcodina

• Free-living
• Few parasitic species in animal intestines
• Thrive in fresh water, salt water, and soil
• Use pseudopods (false feet finger-like
  projections)
• Provide motility through extension and retraction
• Allow organism to feed by engulfing food
  particles
• E.g. Amoebas, foraminiferans, radiolarians,
  heliozoans

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E.g. Amoeba

• Largest and least complex protozoan
• Two layers of cytoplasm
• Ectoplasm thin, semi-rigid layer under plasma
  membrane
• Endoplasm more fluid, fills the inside of the
  cell
• Named chaos chaos by Linnaeus
• Continuous movement of endoplasm causing amoeba
  to constantly change shape

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E.g. Amoeba (2)

• Feeds by phagocytosis
• Pseudopods flow around and engulf food particles
• Food then enclosed in food vacuole
• Contractile vacuole collects excess water
  discharges it through pore in plasma membrane
• Asexual reproduction
• Binary fission
• Typically 1 division a day

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2. Phylum Mastigophora

• Motile
• Move through use of flagella (one or more!)
• Free-living forms found in both fresh and salt
  water
• Majority are parasitic
• Live within other organisms
• Causing disease in animals
• Asexual reproduction
• Longitudinal fission
• Flagellates also form cysts
• Way in which many parasitic forms are spread from
  host to host
• E.g. Giardia lamblia

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Giardia lamblia Beiber fever
NOT QUITE. BEAVER FEVER
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E.g. Giardia lamblia (Beaver Fever)

• Parasite that causes stomach upset and diarrhoea
• Can have more severe effects in some individuals
• Cattle and wild animals often have the parasite
• Infection occurs when we drink or eat food
  tainted with the feces of these infected animals
• BOIL WATER if consuming directly from a stream

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3. Phylum Ciliophora

• Most complex and advanced of the protozoans
• Characterized by cilia
• Hair-like projections
• Shorter and more abundant than flagella
• Can cover the entire organism
• Motile organisms have cilia synchronized for
  swimming
• Non-motile (sessile) organisms use cilia for
  attachment
• Can undergo asexual (binary fission) or sexual
  reproduction (conjugation)
• Live in both freshwater and marine habitats
• E.g. Paramecium

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REVIEW TIME
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E.g. Paramecium

• Most commonly studied ciliate
• Oral groove contains mouth
• Connects to gullet
• Cilia in gullet sweep bacteria and food particles
  into the cavity
• Digestion takes place in food vacuole
• Waste expelled through anal pore
• Excess water collected in contractile vacuole

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E.g. Paramecium (2)

• Two nuclei
• Large macronucleus controls majority of cell
  activities
• Smaller micronucleus involved with reproduction
• Reproduction often asexual (binary fission), can
  undergo sexual (conjugation)
• After conjugation, daughter cells undergo binary
  fission
• Defence mechanism
• Hundreds of poison-laden barbs (trichocysts) can
  be discharged to drive away predators and capture
  prey

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4. Phylum Sporozoa

• Lack means of independent locomotion
• Some have flagella while maturing
• Display complex life cycles
• Exclusively parasitic
• Depend exclusively on body fluids of host for
  movement
• Simple structure with fewer organelles and
  specialized structures
• Characterized by a spore-like stage
• Reproductive cells that can produce a new
  organism without fertilization (sporozoites)
• In cases where two hosts are involved
  reproduction is sexual in one host, asexual in
  the other host
• Insects are frequently vectors responsible for
  transmission

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E.g. Plasmodium

• Notorious P.R.O.T.I.S.T.
• Responsible for causing malaria in humans, other
  mammals, and birds
• Malaria is a disease caused by the plasmodium
  parasite (phylum Sporozoa)
• Transmitted by the female anopheles mosquito
• Nearly half a billion people get Malaria each
  year nearly one million die of the disease
• Sub-Saharan Africa suffers 90 of all Malaria
  deaths

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3 reasons why we still havent gotten rid of
malaria

• List the three reasons Sonia Shah believes are
  responsible for the prevalence of malaria in
  modern day society
• Be PREPARED to discuss these, along with any
  other questions/facts relating to malaria!

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Fungi-like Protists

• Heterotrophs, decomposers, and external digesters
• Exhibit complex life cycles and exist in various
  cellular forms

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1. Gymnomycota (Slime Moulds)

• Prefer cool, shady, moist places
• Often under rotting logs, fallen leaves
• Leave slimy trail as they move along the ground
• At some point in life cycle resemble protozoans
  (amoeba-like, have flagella, etc.)
• At other points, they produce spores
• Do not always remain as single celled organisms
• Becoming multicellular is a TREMENDOUS
  advancement!
• Lays groundwork for cell specialization

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2. Oomycota (Water Moulds)

• Found notably in fresh water environments
• As well as upper surface of moist soil
• E.g. Downey mildews and white rusts
• Produce filamentous hyphae
• Decomposers

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• Create a table to COMPARE/CONTRAST the three
  groups of PROTISTS that we have examined as a
  class (plant-like, animal-like, and fungi-like).
• Be sure to include EXAMPLES OF ORGANISMS that we
  have discussed, as well as the MAIN SIMILARITIES
  and the MAIN DIFFERENCES between and within these
  groupings.