Microbial Diversity

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Microbial Diversity

• Chapt. 28 The Origins of Eukaryotic Diversity

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What are microbes?

• Single-celled organisms and some non-cellular
  parasites

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Kinds of microbes

• Non-cellular, parasitic molecules
• Viruses
• Viroids
• Prions
• Prokaryotes
• Domain Bacteria
• Domain Archaea
• Eukaryotes
• Several Kingdoms in Domain Eukarya

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Carl Woeses 3 Domains of Life
Based primarily on genetic sequence datae.g.,
small subunit ribosomal RNA present in all
organisms
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Eukaryotes

• Kingdoms of Protists within the Domain Eukarya

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Eukaryotes

• Protists
• Complex cellular structure cells with
  nucleus and other organelles

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Eukaryotic cell
Many membranous organelles
including mitochondria, which are common to all
eukaryotes
and chloroplasts (found only in
photosynthesizers)
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Eukaryotes

• Protists
• Complex cellular structure cells with
  nucleus and other organelles

E.g., cilia flagella aid motility these
cytoplasmic extensions are not homologous with
pili or flagella of prokaryotes
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Eukaryotes

• Protists
• Complex cellular structure cells with
• nucleus and other organelles
• Nutrition Absorption, Photosynthesis, or
  Ingestion

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Eukaryotes

• Protists
• Complex cellular structure cells with
• nucleus and other organelles
• Nutrition Absorption, Photosynthesis, or
  Ingestion
• Reproduction mostly asexual, but some
  exchange genetic material

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Asexual cell division (mitosis)
Conjugation exchange of some genetic material
across a cytoplasmic bridge
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Sexual reproduction via the formation and union
of gametes or other haploid cells (requires
meiosis)
Sexual, spore-forming cells of a slime mold
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Eukaryotes

• Protists
• Complex cellular structure cells with
  nucleus and other organelles
• Nutrition Absorption, Photosynthesis, or
  Ingestion
• Reproduction mostly asexual, but some
  reproduce sexually
• Cysts resting stages through harsh
  conditions

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Eukaryotes

• Protists
• Arose from endosymbiosis

Compelling evidence for Lynn Margulis theory is
found in the genetic material of mitochondria
plastids
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Eukaryotes
Ancestral prokaryote
Macroevolutionary timeline
Figure 26.13
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Eukaryotes
Infolding of plasma membrane to form endoplasmic
reticulum and nuclear envelope
Ancestral prokaryote
Macroevolutionary timeline
Figure 26.13
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Eukaryotes
Infolding of plasma membrane to form endoplasmic
reticulum and nuclear envelope
Ancestral prokaryote
Engulfing of heterotrophic prokaryote
Macroevolutionary timeline
Figure 26.13
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Eukaryotes
Infolding of plasma membrane to form endoplasmic
reticulum and nuclear envelope
Ancestral prokaryote
Engulfing of heterotrophic prokaryote
Mitochondrion
Macroevolutionary timeline
Figure 26.13
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Eukaryotes
Infolding of plasma membrane to form endoplasmic
reticulum and nuclear envelope
Engulfing of photosynthetic prokaryote
Plastid
Ancestral prokaryote
Engulfing of heterotrophic prokaryote
Mitochondrion
Macroevolutionary timeline
Figure 26.13
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Eukaryotes
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
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Eukaryotes
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
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Eukaryotes
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
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Eukaryotes
Plastid
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
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Eukaryotes
Plastid
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
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Eukaryotes
Plastid
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
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Eukaryotes
Plastid
Dinoflagellates
Apicomplexans
Secondary endosymbiosis
Cyanobacterium
Ciliates
Red algae
Primary endosymbiosis
Stramenopiles
Heterotrophic eukaryote
Plastid
Euglenids
Secondary endosymbiosis
Figure 28.3
Green algae
Chlorarachniophytes
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Eukaryotes

• Protists
• Arose from endosymbiosis
• Various lineages gave rise to all modern
  unicellular colonial protists, as well as
  all multicellular organisms (some protists, as
  well as all plants, fungi, and animals)

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Paraphyletic distribution of protists within a
tentative phylogeny of Eukarya
Choanoflagellates
Diplomonadida
Parabasala
Euglenozoa
Chlorophyta
Rhodophyta
Cercozoa
Radiolaria
Animalia
Plantae
Fungi
Alveolata
Stramenopila
Amoebozoa
Ancestral eukaryote
An ancestor and only some of its descendents
Figure 28.4
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Hypotheses for the earliest stages of biological
diversification
Last Universal Common Ancestor
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Hypotheses for the earliest stages of biological
diversification
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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Fungus-like protists
• Heterotrophic
• Absorption

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Fungus-like protists
• Heterotrophic
• Decomposers
• E.g., slime molds

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Fungus-like protists
• Heterotrophic
• Parasitic
• E.g., water molds

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Plant-like protists
• Autotrophic
• Photosynthesis

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Plant-like protists
• Autotrophic
• Unicelluar
• E.g., Euglena

Phytoplankton (unicellular algae cyanobacteria
prokaryotes 70 of all photosynthesis)
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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Plant-like protists
• Autotrophic
• Multicelluar
• E.g., Many
• seaweeds

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Animal-like protists
• Heterotrophic
• Ingestion

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Animal-like protists
• Heterotrophic
• Free-living
• E.g., Some amoebae

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Animal-like protists
• Heterotrophic
• Parasitic
• symbionts
• E.g., Giardia

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Animal-like protists
• Heterotrophic
• Mutualistic symbionts
• E.g., protists of termite guts

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Eukaryotes

• Protists
• Highly diverse genetically and
• phenotypically
• Animal-like protists
• Heterotrophic
• Exhibit slightly more complex behavior
  than prokaryotes

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Predator-prey interaction between
ciliates Didinium preys upon Paramecium