Review
The three domains of life
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Figure 28.05
The Four Supergroups of Eukaryotes
Parabasalids
Euglenozoans
Excavata
Archaeplastida
5 µm
20 µm
25 µm
Stramenopiles
Diatoms
Brown algae
Oomycetes
SAR
Alveolates
Dinoflagellates
Apicomplexans
SAR
50 µm
Unikonta
Ciliates
Radiolarians
Rhizarians
Forams
Cercozoans
Green
algae
Chlorophytes
Charophytes
Plants
Fungi
Choanoflagellates
Animals
Unikonta
Amoebo- Opisthozoans
konts
Tubulinids
Slime molds
Entamoebas
Nucleariids
Archaeplastida
Red algae
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Excavata
Diplomonads
100 µm
SAR
100 µm
Protists
Protists do not form a true phylogenetic (monophyletic) group
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Supergroup: Excavata
Many members have
feeding groove used to capture and ingest small particles
Example: Euglenozoans
Crystalline rod inside the flagella
Figure 28.08
Flagella
0.2 µm
8 µm
Crystalline rod
(cross section)
Ring of microtubules
(cross section)
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Kinetoplastids (an example of a Euglenozoan)
– Have a single, large mitochondrion that
contains an organized mass of DNA called a
kinetoplast (consists of many copies of the
mitochondrial genome)
Example: Trypanosoma brucei gambiense:
causes West – and African sleeping sickness,
transmitted by tsetse fly
Figure 28.09
Trypanosome
Red blood
cells
9 µm
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Trypanosoma
Slide to observe
Euglenids
(an example of a Euglenozoan)
Two flagella. Flagella are long, cytoplasmic extensions supported by a
spiral or crystalline rod. Chloroplast of secondary origin bounded by
three membranes. Chlorophyll a, and b
Some are mixotrophic: photosynthesize when sunlight is available,
otherwise heterotrophic
Flagella
0.2 µm
Paraflagellar rod
Ring of microtubules
Euglena
Campbell 10th
Supergroup: SAR
Stramenopiles, Alveolates, Rhizarians
Grouped based on DNA sequence similarities
Stramenopiles
(e.g. Diatoms, Brown Algae)
Common characteristic:
In most cases, during development, they have cells
with “hairy” flagellum, which is often paired with
a “smooth” flagellum
Hairy
flagellum
Smooth
flagellum
5 µm
Diatoms (Greek- cut in half)
• Major component of phytoplankton
• Highly diverse, unicellular algae with a unique
two-part, glass-like wall of hydrated silica
embedded organic matrix material
Male gametes have hairy flagella
Example of diatoms
Slide made from diatomaceous earth
Navicula
Live specimen
Wikipedia
•
Brown algae (Phaeophyta)
– Include many of the species commonly called seaweeds
– Have the most complex multicellular anatomy of all algae (e.g. kelps)
– Spores and male gametes have hairy flagella
– Pigment fucoxanthin (brown)
– Intercellular, edible mucilaginous polysaccharide, alginate
Blade
Stipe
Holdfast
Sea palm
Nereocystis
Sargassum
Sargassum
© 2013, 2005, 1999, 1993 by W. H. Freeman and Company
Alveolates (member of SAR)
Examples: Ciliates, Dinoflagellates, Apicomplexans
Common characteristic:
Presence of membrane-enclosed sacs,
alveoli, under the plasma membrane.
Some are heterotrophic, others photosynthesize
Figure 28.16
Flagellum
Alveoli
0.2 µm
Alveolate
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Ciliates
Common characteristic: two types of nucleus, move with cilia,
Live specimen
Figure 28.19a
Paramecium
Contractile vacuole
Oral groove
50 µm
Cilia
Micronucleus
Macronucleus
(a) Feeding, waste removal, and water balance
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Cell mouth
Food
vacuoles
Paramecium
Fission of Paramecium
Slide
Paramecium conjugation
Slide
Dinoflagellates
– Are a diverse group of aquatic photoautotrophs and
heterotrophs
– Are abundant components of both marine and
freshwater phytoplankton
Common characteristic:
Two flagella - typically one in transverse orientation, make them
spin as they move through the water
Many but not all species are reinforced by internal plates of
cellulose
Figure 28.17
(a) Dinoflagellate
flagella
Flagella
4 µm
(b) Red tide in the
Gulf of Carpentaria
in northern Australia
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Zooxanthellae – symbiotic dinoflagellates
© 2013, 2005, 1999, 1993 by W. H. Freeman and Company
Peridinium sp.
Live specimen
Dinoflagellates on slide
Apicomplexans
Single celled parasites of animals and some cause serious human
diseases such as malaria
Common characteristic:
At least one stage of the life cycle with an apical complex
at one end of the cell, specialized for penetrating host cells
and tissues
Plasmodia in red blood cells
Anopheles mosquito, a carrier of Plasmodium
Plasmodium falciparum – 90% of the deaths of malaria infections
Rhizaria (a group in SAR)
(e.g. Foraminiferans, Radiolarians)
Common characteristic:
Amoebas with threadlike pseudopodia often supported by
microtubules
Foraminifera (hole bearers) or Forams
Common characteristic:
Reticulopodia emerge through shell pores and form dense
networks.
Reticulopods are used to capture food (other protists, bacteria),
and to crawl.
Unicellular, mainly marine, bottom dwelling protists, some are
planktonic.
Forams host a variety of photoautotrophic algae.
Multi-chambered, calcium carbonate tests (shell)
A foram: Globigerina
A foram
Slide
Radiolarians
Common characteristic:
Axopodia: pseupodia reinforced by radiating microtubulesextending in all directions
Unicellular, spherical, mainly planktonic protists with r
igid endoskeleton consisting mainly of silica
Raptorial, but many have symbiotic algae.
Lamprocyclas - a radiolarian
Slide
A radiolarian -
Unikonta (“having a single flagellum”)
Group based on molecular data
In addition to protists, it includes animals and fungi
Amoebozoan
Common characteristic:
lobe- or tube-shaped pseudopodia
Tubulinids- e.g. Amoeba proteus
https://www.youtube.com/watch/
7pR7TNzJ_pA
Study guide
Know characteristics that distinguish one group of protists from other groups
Study the sample organisms for the groups covered above
Study the important human pathogens covered (Trypanosoma, Plasmodium)
Recognize organisms in the pictures/slides
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