Protists Outline

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Protists - Outline

• Reading Chap. 28, Chap. 13 pp.234-239
• I. Introduction
• A. Diversity of life styles
• B. Functional classifications
• C. Kingdom Protista?
• II. Ecological importance
• III. Life cycles
• A. Meiosis and mitosis
• B. The three basic types

IV. Evolutionary history A. How did they
arise? B. How are they related to each other? C.
How are they related to plants and animals?
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I.A. Diversity of life styles
1. Size 2. Morphology 3. Motility 4. Energy
sources
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Size
10 mm
6 orders of magnitude!
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Morphology
Filamentous (Golden algae)
Unicellular (Euglena)
Colonial (Volvox)
Multicellular (kelp)
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Motility
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Energy source - photoautotrophs
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Energy source - heterotrophs
Particle feeder (Stentor)
Parasite (Trypanosoma)
Decomposer (slime mold Physarum)
Predator (Amoeba)
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I.B. Functional classifications

• Protozoans - animal like
• Algae - plant-like, i.e., photosynthetic
• - Eukaryotic photosynthetic organisms that are
  not plants
• Mix - simple to bizarre
• Dont necessarily relate to taxonomic
  relationships and evolutionary history

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Mixotroph example - Euglena
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Bizarre example - Cellular slime mold

• Fig. 28.30

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I.C. Kingdom Protista?
Fig. 28.2
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Protists are not a natural group (clade)

• Whats a natural group?
• Monophyletic and not paraphyletic
• Protists are both polyphyletic and paraphyletic
• Any questions?

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Monophyletic vs. Polyphyletic
Fig. 25.9
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Whats paraphyletic?
Fig. 25.9
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II. Ecological importance

• A. Algae
• B. Protozoans

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Algae Base of the food chain
Starr, Fig. 37.3 - Antarctic food web
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Algae Eutrophication
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Algae Toxicity - red tides, Pfiesteria
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Algae Global Carbon Cycling
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Algae Useful products
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Algae Habitat
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Algae mutualisms
Corals (cnidarian dinoflagellate)
Lichens (fungus plus green algae)
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Protozoans Decomposition and nutrient cycling

• (draw)

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Protozoans Disease
Trypanosomas sleeping sickness
Giardia
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Plasmodium malaria
Fig. 28.13
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III. Life cycles

• A. Meiosis and Mitosis the simple picture
• B. The three basic types
• 1. Gametic (animal-like)
• 2. Zygotic (fungus-like)
• 3. Sporic alternation of generations (plant-like)

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A. Meiosis and Mitosis The simple picture

• 1. Mitosis bottom line
• one cell --gt two identical cells
• same ploidy as parent cell

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A. Meiosis and Mitosis The simple picture

• 2. Meiosis bottom line
• One cell --gt four cells
• ploidy is one half that of the parent cell
• some mixing of chromosomes occurs - daughter
  cells are not identical

1n
1n
2n
1n
1n
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B. Life cycles the three basic types (draw)
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1. Gametic (animal-like)
Fig. 13.5

• Fucus

Raven et al. 1999
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2. Zygotic (fungus-like)

• Chlamydomonas Fig. 28.24

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3. Sporic (plant-like)
Alternation of generations

• Laminaria Fig. 28.21

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3. Sporic variations

• a. Isomorphic
• b. Heteromorphic
• i. Gametophyte dominant
• ii. Sporophyte dominant

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IV. Evolutionary history

• A. How did eukaryotic protists arise?
• B. How are they related to each other?
• C. How are they related to higher plants?

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A. Endosymbiosis

• How did they arise?

Fig 28.4 Origin of early eukaryotes
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Secondary endosymbiosis
Fig. 28.5 Secondary endosymbiosis
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Secondary endosymbiosisCryptomonads
- Chlorophylls a and c - Phycobilins - otherwise
known only in red algae and cyano- bacteria
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Figs. 28.6 - LUCA
Figs. 28.7 - Multiple events
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B. Phylogeny

• How are they related to each other?

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A tentative phylogeny of the eukaryotes

• Points
• 1. Plant, animal, and fungal kingdoms are intact
• 2. Different main groupings of protists are often
  considered to be kingdoms

Fig. 28.8
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A tentative phylogeny of the eukaryotes

• Points
• 3. Photosynthetic and non-photosynthetic phyla
  are often more closely related to each other than
  to other phyla of similar lifestyle.
• 4. Many taxa are not included in this figure -
  either not presented in the text or phylogeny is
  still too tentative.

Fig. 28.8
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C. Evolution

• How are they related to higher plants and animals?

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Green algae and plants

• Algae are eukaryotic photosynthetic organisms
  that are not plants.
• So, what are the defining characteristics of
  plants?
• - Chlorophyll a and b
• - Starch as a storage polymer
• - Cell walls of cellulose (plus other polymers)
• - rosette cellulose synthesizing compounds
• - peroxisome enzymes
• - phragmoplast

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Charophyceans and plants

• Table
• Trait Charo Land plants