Protozoa Protists

Single-cell eukaryotes

Single-cell "microbial eukaryotes".

Or colonies (as individuals)

Linnoean Classification System

Domain > Kingdom > Super Group (Phyla) > Phylum > Class > Order > Family > Genus > Species > Sub-Species

Speciation

Endosymbiotic Theory

Horizontal gene transfer via eukaryotes engulfing mitochondria and chloroplasts.

Reproduction w/o Sex

Binary Fission

Asexual, Clones

Sex w/o Reproduction

Gene shuffling between micronuclei in ciliates.

Protozoa Phyla

Aveolates

Membrane 'aveolar' sacs just under cell membrane.

• Dinoflagellates
• Apicomplexan
• Cillates

Stramenopiles

• Diatoms - photosynthetic, silicon dioxide glass shells
• Brown algae - photosynthetic.

Rhizarians

Excavates

Kinetoplastids

Amoebozoans

True amobeas, slime molds, cellular slime

Study Guide

• Notice:

  • Kingdom PROTISTA (simple eukaryotes) is an outdated term.
  • The MICROBIAL EUKARYOTES are a mixed bag of traits.
    • Some traits are similar to those seen in prokaryotes.
    • Many are new traits arising in more complex cells.
  • Throughout the slides:
    • Click/watch the videos (blue hyperlinks – hover over and click to follow link).
    • You may need to control-click or right-click to open hyperlinks.
• 1. Taxonomy & Diversity
  • Would a Phylum encompass more diversity as a large diverse group or a small focused group of organisms?
  • What are the two smallest, most specific taxonomic classification groups?
  • What is more inclusive/broad: species or genus?
• 2. Protists Today
  • How are Protists (Protista) defined today?
    • Microbial eukaryotes, usually single-celled.
  • What do they all have in common?
    • What eukaryotic traits distinguish protists from prokaryotic cells?
      • Organelles, linear DNA, and no peptidoglycan.
• 3. Clades & Phylogeny
  • Note the five microbial eukaryote clades.
    • Are they monophyletic? Why or why not?
  • What is monophyletic vs. polyphyletic?
• 4. Reproduction
  • Are microbial eukaryotes asexual or sexual in replication?
    • Either or both
• 5. Motility
  • Notice different forms of motility in microbial eukaryotes (or if not mobile).
  • What do eukaryotic flagella and cilia have in common?
    • They're both contained in the cell membrane.
  • How are eukaryotic flagella different from prokaryotic flagella?
    • Hint:
      • Type of protein
        • Eukaryotic flagella use dynein proteins, prokaryotic flagella use flagellin.
      • Enveloped or not by cell plasma membrane
        • Eukaryotic flagella are enclosed in a membrane, prokaryotic flagella aren't.
      • Movement direction
        • Eukaryotic flagella wave side to side, prokaryotic flagella rotate circularly.
      • Energy source
        • Eukaryotic flagella use ATP, prokaryotic use proton gradients.
• 6. Alveolata Superphylum
  • a. Apicomplexans
    • Name a couple of Apicomplexans.
      • Toxoplasma and plasmodians
    • What organelle is special to them?
      • Alveolar sacks
    • Which major lethal human disease is carried by mosquitoes?
      • Malaria
    • What are its two animal hosts?
      • Mosquitoes and humans (red blood cells)
    • Is it sexual or asexual?
      • Sexual in mosquitoes, asexual in humans
    • Where in the world are these diseases common?
      • Where there are mosquitoes and the lack of sickle cell heterozygous traits.
    • What hints tell us that they cause selective pressure in humans?
      • Sickle cell
  • b. Malaria
    • What is malaria?
    • What are its hosts?
    • How does it invade host cells?
    • Where does it replicate?
  • c. Ciliates
    • What structure is special to ciliates? Name one.
      • Cilia
    • What enables them as predators? What “cool weapon” do they use?
      • Trichocysts act as harpoons.
    • How do they move?
      • Hundreds of little tiny cilia as like flagella like a viking rowboat.
    • What is interesting about Paramecium sex and reproduction?
      • They can reproduce without sex or have sex without reproduction.
    • What are the roles of the two different nuclei of Paramecium?
      • Which one is for genetic reshuffling (sex)?
        • The micronucleus.
      • What is the purpose of the other (macro) nucleus?
        • It's focus is gene expression.
  • d. Dinoflagellates
    • Notice dinoflagellates are not diatoms.
    • What is so important to Earth’s food chain and animal health regarding dinoflagellates?
      • They produce bioluminescent pigments, and they produce oxygen.
• 7. Stramenopile Supergroup
  • a. Diatoms
    • What is significant about diatoms in the environment?
    • What is in their shells making them so refractile to light?
    • Notice diatoms are not dinoflagellates.
  • b. Brown algae
    • Name some types of brown algae.
    • Where are they found?
• 8. Rhizaria Supergroup
  • a. Foraminifera
    • What is significant about the Foraminifera phylum?
    • How are their cell surfaces unique vs. other groups?
  • b. Remnants
    • Where do we see remnants of Foraminifera organisms today?
• 9. Excavata Supergroup
  • a. Human parasites
    • Describe at least two parasites that infect humans from this phylum:
      • Mode of infection
      • Hosts
      • How one contracts the parasite
  • b. Euglena
    • What is unique about the Euglena phylum?
• 10. Amoebozoan Supergroup
  • a. Shared traits
    • What two traits do all Amoebozoans have in common that differentiate them from other motile unicellular eukaryotes?
  • b. Differences
    • How are the three amoeboid-like organisms shown different from each other?
• 11. Cytoskeletal-based motility
  • What are the two major types of cytoskeletal-based motility in eukaryotes?
  • a. Details
    • Know the different proteins involved.
    • What types of movements exist?
    • Which microbial eukaryotes are sessile?
      • What does sessile mean?
• 12. Life cycles & genetics
  • a. Genetic states
    • What does haploid and diploid mean?
    • What do haplontic, diplontic, and haplodiplontic life cycles mean?
  • b. Reproduction
    • What distinguishes sexual reproduction from asexual reproduction?
  • c. Major genetic state
    • What is the major genetic state of haplontic vs. diplontic organisms?
  • d. Examples
    • Name some organisms classified as:
      • Haplontic
      • Diplontic
      • Haplodiplontic
    • If you see a microbial eukaryote lifecycle on the slides, which of these three types does it resemble?
• 13. Phylogeny
  • Notice where the microbial eukaryotes sit on a large phylogeny.
  • How are they positioned relative to plants, fungi, and animals?