Protists - Outline
Announcements
• Relevant reading BEFORE lab this week: Ch. 31
• Bring lab atlas AND textbook to lab.
• Extra credit opportunity:
– Salmon Summit: Wed. 11/3/10, 8-4:45 pm
St. Luke’s Community Health Education Center
Bellingham, WA (checking on registration)
Reading: Chap. 29
I. Introduction
IV. Evolutionary history
A. Diversity of life styles
A. Kingdom Protista?
B. Functional classifications
B. How are they related
II. Ecological importance
to each other?
A. Algae
C. How did they arise?
B. Protozoans
D. How are they related
to plants?
III. Life cycles
A. The three basic types
B. Examples
Diatom
I.A. Diversity of life styles
Size
10 μm
1. Size
2. Morphology
3. Motility
4. Energy sources
Kelp
6 orders of magnitude!
60 m
Filamentous
(Golden algae)
Gradient in complexity
Morphology
Unicellular (Euglena)
Colonial
(Pandorina)
Multicellular (kelp)
1
Crawling (pseudopodia)
Cell walls – protection & support
Planktonic
Amoeba
Diatoms
Cilia
Flagella
Motility
Fastened
Amoeba
Paramecium
Euglena
Kelp
No cell wall
Energy source - photoautotrophs
Variation in photosynthetic pigments
Energy source - heterotrophs
Ingestive feeders
Absorptive feeders: decomp., parasites
I.B. Functional classifications
Particle feeder
(Stentor)
Parasite
(Trypanosoma)
Decomposer
(slime mold
Physarum)
(ingestive)
Protozoans - “animal like”
Algae - “plant-like”, i.e., photosynthetic
- Eukaryotic photosynthetic organisms
that are not plants
Mix - simple to bizarre
Don’t necessarily relate to taxonomic
relationships and evolutionary history
Predator
(Amoeba)
2
Mixotroph example - Euglena
Cellular slime mold – unicellular or multicellular?
Cells (n) aggregate
when food is scarce
Amoebae (n)
germinate
from zygote
SEXUAL
REPRODUCTION
Amoebae (n) germinate
from spores
Spores
(n)
ASEXUAL
REPRODUCTION
Fruiting
body
Stalk
Giant cell
(2n)
Two cells (n) in aggregation fuse,
then consume other cells
Migrating individual
(slug) (n)
Fig. 29.9
Algae: Base of aquatic food webs
II. Ecological importance
A. Algae
B. Protozoans
Starr, Fig. 37.3 - Antarctic food web
Algae: Eutrophication
Fig. 28.4
Algae: Toxicity - red tides, Pfiesteria
Dinoflagellates
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Algae: Global Carbon Cycling
Algae: Useful products
Food
Emulsifiers
http://www.laurensveganjournal.org/pictures/Sushi.jpg
Carrageenan
Smith, fig. 12.7
http://www.fitsugar.com/Should-You-Avoid-Carrageenan-1074330
http://www.danisco.com/wps/wcm/connect/www/corporate/media/news/company_news/2004/june/news_97_en.htm
Algae: mutualisms
Macro-algae: Habitat
Lichens - fungus plus green algae;
(sometimes cyanobacteria)
Corals - cnidarian + dinoflagellate
Protozoan with endosymbiotic green algae
Protozoans: Disease
Plasmodium: malaria
Plasmodium: malaria
Trypanosomas: sleeping sickness
See Table 28.1
Giardia
Fig. 28.13
4
A. Life cycles: the three basic
types (draw)
III. Life cycles
A. The three basic types
B. Examples
1. Gametic (animal-like)
2. Zygotic (fungus-like)
3. Sporic: alternation of generations (plant-like)
B. Examples
1. Gametic (animal-like)
2. Zygotic (fungus-like)
C&R, Fig. 13.5
Dinoflagellates
Diatoms
3. Sporic (plant-like)
3. Sporic variations
a. Isomorphic
Laminaria Fig. 28.22b
“Alternation of generations”
Fig. 28.22a
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3. Sporic variations
IV. Evolutionary history
b. Heteromorphic
i. Gametophyte dominant
ii. Sporophyte dominant
IV.A. Kingdom Protista?
A. Kingdom Protista?
B. How are they related to each other?
C. How did eukaryotic protists arise?
D. How are they related to higher plants?
Protists are not a natural group
(clade)
What’s a natural group?
Monophyletic and not paraphyletic
Protists are paraphyletic
Any questions?
Fig. 29.1
Are protists a natural monophyletic group?
What’s paraphyletic?
B. Phylogeny
How are they related to each other?
28.8
C&R Fig. 25.9
6
A tentative phylogeny of the eukaryotes
A tentative phylogeny of the eukaryotes
Some have
endosymbiotic
algae
Fig. 29.8
Fig. 29.8
Points
Points
1. Based on both morphological and DNA evidence
2. 7-8 main groupings of eukaryotes (Discicristata Æ Excavata;
Cercozoa = Rhizaria); 2 of which include plants and
fungi/animals
C. How did Protists arise?
Endosymbiosis?
5. Photosynthetic and non-photosynthetic phyla are often more closely
related to each other than to other phyla of similar lifestyle.
6. Many taxa are not included in this figure - either not presented in the text
or phylogeny is still too tentative.
Mitochondrial and Chloroplast DNA
C&R Fig 28.4 (see also Freeman 29.11 or 29.8) Origin of early eukaryotes
How did photosynthesis spread?
Secondary endosymbiosis
Secondary endosymbiosis:
Cryptomonads
- Chlorophylls a and c
- Phycobilins
- otherwise known only
in red algae and cyanobacteria
C&R, Fig. 28.5 Secondary endosymbiosis
Freeman Fig. 29.16 (or 29.13)
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Bacteria
Archaea
Eukarya
Eukarya
Discicristata Chromalveolates
ac
ria ea
te ha
rc
A
D. How are they related to higher plants?
Plantae
s
te e
hy ga
op al
e ra ni te
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e lga ant
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pl
n m i r ar c o al g n a
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fla om yc
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gl lia ino pic om iato row ora hlo lau ed ree and
A O
L
R G
Eu Ci D
B F C G
D
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B
Rhizaria
s
xa
Secondary
endosymbiosis:
A green algal chloroplast
was transferred to the
ancestor of the euglenids and
to the chlorarachniophytes
Primary (initial)
endosymbiosis:
occurred here
Secondary endosymbiosis:
A red algal chloroplast was
transferred to the ancestor
of the chromalveolates
29.17 – Photosynthesis in protists arose by primary
endosymbiosis, and spread by secondary endosymbiosis
Green algae and plants
Algae are eukaryotic photosynthetic organisms that
are not plants.
So, what are the defining characteristics of plants?
- Alternation of generations (sporic life cycle)
- Chlorophyll a and b
- Starch as a storage polymer
- Cell walls of cellulose (plus other polymers)
- rosette cellulose synthesizing compounds
- peroxisome enzymes
- phragmoplast
End here
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