Chapter 23: Protistans

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Chapter 23Protistans
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branch leading to fungi
branch leading to animals
branch leading to plants
charophytes
Stramenopiles
amoeboid protozoans
green algae
Alveolates
brown algae
ciliates
chrysophytes
red algae
apicomplexans
oomycotes
dinoflagellates
crown of eukaryotes (rapid divergence)
slime molds
euglenoids
parabsalids (e.g., Trichomonas)
kinetoplastids (e.g., Trypanosoma)
diplomonads (e.g., Giardia)
protists
endosymbiotic origins from prokarytic ancestors
Fig. 20-2, p.316
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I. Traditional Protista Organization

• A. Fungi-like protists Molds
• B. Animal-like protists Protozoans
• a. Amoeboids
• b. Ciliates
• c. Flagellated Protozoans
• C. Plant-like Protists Algae
• a. Dinoflaggelates
• b. Red Algae
• c. Brown Algae
• e. Green Algae

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II. More Recent Organization

• Flagellated Protozoans (animal-like protists with
  flagella)
• 1. Human importance Giardia, African
• Sleeping Sickness, Chargas Disease.
• 2. Example Euglenoids, such as euglena.
• Single cell, free-living
• organism. About 30 are
• autotrophic. Contain
  contractile vacuole.

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Euglena Plant-like ? Some are photosynthetic,
other heterotrophs. No cell wall but flexible
cell coat. Motile and eukarytoic.
long flagellum
contractile vacuole
chloroplast
eyespot shielding a light-sensitive receptor
ER
Fig. 23.15, p. 383
Golgi body
nucleus
pellicle
mitochondrion
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II. More Recent Organization

• 3. Variety in Euglena due to primary
• endosymbiosis (engulf bacteria).

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II. More Recent Organization

• Alveolates Broad group with small sacs under
  their plasma membrane.
• 1. Ciliates Move with cilia (many small
  extensions). Example Paramecium. Most are
  heterotrophs.

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food residues being ejected
gullet
cilia
food vacuole
trichocysts (harpoons)
contractile vacuole emptied
contractile vacuole filled
macronucleus
micronucleus
cillium
pellicle
intact trichocyst
basal body of cilium
Fig. 23.6b-d, p. 378
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Fig. 20-6b, p.318
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II. More Recent Organization

• B. Alveolates Broad group with small sacs under
  their plasma membrane.
• 2. Dinoflagellates Algae and/or predators.
• a. Algae inside corals.
• b. Red tide algae (video clip).

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Fig. 20-9b, p.319
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II. More Recent Organization

• B. Alveolates
• 3. Malaria Caused by Plasmodium.
• Sporozite (liver), Merozoites (liver
  
• and blood), gametes (blood, passed
• to mosquitoes)

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sporozoite
sporozites
1 In the gut of a female mosquito carrying the
malarial parasite Plasmodium, zygotes of the
parasite develop into sporozoites, which migrate
to her salivary gland.
2 Mosquito bites a human, sporozoites enter
bloodstream and reach liver.
3 Sporozites reproduce asexually in liver cells.
5 Some merozoites return to liver and are basis
for more episodes of malaria.
merozoite
6 Other merozoites develop into male and female
gametocytes, which are released into bloodstream.
4 Progeny (merozoites) enter bloodstream, invade
red blood cells, and reproduce asexually. They
may do so many times over a prolonged period.
Disease symptoms (fever, chills, shaking) become
more and more severe.
7 A biting female mosquito sucks blood from
infected human. Gametocytes in the blood reach
her gut, mature into gametes used in sexual
reproduction. Gametes fuse to form zygotes.
male gametocyte in red blood cell
Fig. 23.14, p. 382
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II. More Recent Organization

• C. Stramenopiles
• 1. Some fungi-like organism potato
• blights and water molds.
• 2. Diatoms algae with silicate shells.
• 3. Other algae Golden algae and
• coccolithophores.
• 4. Brown Algae Include Kelp.

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Fig. 20-12, p.321
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Fig. 20-13b, p.321
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bladder
blade
stipe
holdfast
Fig. 20-13c, p.321
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II. More Recent Organization

• D. Green Algae
• 1. Many biologist consider these plants,
• use similar photosynthesis pigments,
• cell wall w/ cellulose, make starch
• 2. Chlorophyta largest group

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Fig. 20-16c, p.323
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Fig. 20-16b, p.323
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II. More Recent Organization

• E. Red Algae Often found at depths in saltwater
  environments.

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sporophyte (2n)
zygote
Diploid Stage
Meiosis
Fertilization
Haploid Stage
germinating spore (n)
male gametes
female gametes
Fig. 23.19, p. 386
gametophyte (n)
10 cm
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II. More Recent Organization

• F. Ameoboids Move with pseudopods (false foot)
  and often involve complex cell communication.

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p.314b
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Fig. 20-18a, p.325
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