Download What are algae? What are algae?

Marine botany –
the study of aquatic plants and algae that live in seawater
of the open ocean and the littoral zone and in brackish
waters of estuaries
Algae–
have chlorophyll as their primary photosynthetic pigment
and lack a sterile covering of cells around their reproductive
cells
Macroalgae
- Rhodophyta, Chlorophyta, Ochrophyta
Phycology- study of algae
Microalgae (Phytoplankton)
- Dinophyta , Haptophyta, Ochrophyta
alga (singular) : “I study Silvetia, the intertidal alga”
Angiosperms
-Mangroves, Marsh Plants, Seagrasses
algal (adj.): Algal lunch, algal skirt, algal growth rate
algae (plural): “Algae rock my world”
“algaes” (wrong!)
Cyanobacteria
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What are algae?
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What are algae?
• Polyphyletic group = different ancestors, different
evolutionary histories
AB CD E
monophyletic
or
clade
AB CD E
polyphyletic
AB CD E
AB CD E
paraphyletic
Algae encompassing various distinctly related groups of
aquatic photosynthetic eukaryotes & bacteria.
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Eukaryota Groups
Alveolates- dinoflagellates
Stramenopiles- diatoms, ochrophyta
Rhizaria
Excavates
Plantae- rhodophyta, chlorophyta, seagrasses
Amoebozoans
Fungi
Choanoflagellates
Animals
Groups (Kingdom)
DOMAIN
1.Bacteria- cyanobacteria
2.Archae
3.Eukaryota
1. Alveolates- unicellular,plasma membrane supported by
flattened vesicles
2. Stramenopiles- two unequal flagella, chloroplasts 4
membranes
3. Rhizaria- unicellular amoeboids
4 E
4.
Excavatest
unicellular
i ll l fl
flagellates
ll t
5. Plantae- most broadly defined plant group
6. Amoebozoans- pseudopods for movement & eating
7. Fungi- heterotrophs with extracellular digestion
8. Choanoflagellates- unicellular withsingle flagella
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Groups (Kingdom)
DOMAIN
1.Bacteria- cyanobacteria (blue green algae)
2.Archae
3.Eukaryotes
9. Animals- multicellular heterotrophs
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Defining characteristics of Algae:
“Algae”
1. Alveolates- dinoflagellates
Photosynthesis (photoautotrophic, usually), using Chl a as
primary pigment
2. Stramenopiles- diatoms, ochrophyta
BUT: Limited cellular differentiation compared to
terrestrial plants
3. Rhizaria- unicellular amoeboids
4 Excavates- unicellular flagellates
4.
 No
N “real”
“
l” vascular
l system
5. Plantae- rhodophyta, chlorophyta, seagrasses
 Sex organs unicellular, or all cells capable of
reproduction (no sterile layer of cells
surrounding sex organs aka NO FLOWERS)
6. Amoebozoans- slimemolds
7. Fungi- heterotrophs with extracellular digestion
8. Choanoflagellates- unicellular
9. Animals- multicellular heterotrophs
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 Much greater diversity of photosynthetic pigments
and life histories
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A Vascular plant
flower
stem
An Alga
Algae show tremendous diversity of
form, habitat, and lifestyle
sorus
blade
photo Pete Dal Ferro
stipe
leaf
holdfast
roots
Thallophyte- plants that lack
roots, stems & leaves
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Free-living and unattached
Gymnodinium – planktonic dinoflagellates
Rhodoliths - benthic macroalgae
photo: Morgan Bond
Found in all bodies of water (freshwater, marine intertidal and
subtidal) as well as terrestrial systems with enough moisture31
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3
Epiphytic
Free-living and attached to the substrate
Parasitic
Postelsia palmaeformis
“saxicolous”, or “saxiphytic”
Caulerpa taxifolia
“psammophtyic”
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Symbiotic and Endoymbiotic
Lichen = close association
of an alga and a fungus
Marine: Zooxanthellae in corals, anemonies,
nudibranchs, flatworms
Smithora naiadum on
Phyllospadix torreyi
Trentepohlia on
Monterey Cypress
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Ecological importance of algae
- Primary production; role in species interactions
- Ecosystem engineers: e.g. kelp forests, rhodolith beds, coral
reefs = Create structure that defines the habitat type
Radiolarians, Foramaniferans = ameoba + alga
fH2O too!: Zoochlorellae in hydras, sponges, etc.
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Allochthonous input – external source, not from the same ecosystem
Nutrient input into terrestrial systems & deep sea
Direct importance of algae to human beings
Origin’s of the world’s oil supplies (dinoflagellates,coccolithophores,diatoms)
Used in biological and medical research (e.g. Cyanobacteria, Chlamydomonas;
fucoids);
One product of red algae (e.g. Gelidium, Gigartina) = agar; produces gel at low
temperatures, used in gel electrophoresis. (HUGE in genetics)
Eaten “as itself” (e.g. nori, Spirulina)
Products of algae are everywhere: carrageenan (from red algae) and alginates
(from brown algae, e.g. Macrocystis, Laminaria) from polysaccharides in cell
walls, act as thickening agents
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Algal Taxonomy
Algal Taxonomy
Hierarchical system of classification:
Level:
Domain/Empire
Kingdom/Group
Phylum/Division
Class
Order
Family
Genus
species
Ice cream, mayonnaise, chocolate milk, soy milk, toothpaste, salad dressings,
shaving cream, fertilizers, rubber, paint, hair products
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Hierarchical system of classification:
suffix:
Level:
Domain
Kingdom/Group
Phylum/Division
Class
Order
Family
-phyta
p y
-phyceae
-ales
-aceae
Genus
species
suffix:
-phyta
p y
-phyceae
-ales
-aceae
example:
Eukaryote
Plantae
Chlorophyta
Ulvophyceae
p y
Ulvales
Ulvaceae
Ulva
fenestrata
• King Phillip Came Over For Good Spaghetti
• Keep Dishes Clean Or Family Gets Sick
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Groups (Kingdom)
DOMAIN
1.Bacteria- cyanobacteria (blue green algae)
2.Archae
1. Alveolates- dinoflagellates, coccolithophore
3.Eukaryotes
Algal Taxonomy
Hierarchical system of classification:
Level:
Domain
Kingdom/Group
Phylum/Division
Class
Order
Family
Genus
species
suffix:
-phyta
p y
-phyceae
-ales
-aceae
example:
Eukaryote
Chromista
Ochrophyta
Phaeophyceae
p y
Laminariales
Alariaceae
Egregia
menziesii
Chromista
2. Stramenopiles- diatoms, ochrophyta
3. Rhizaria- unicellular amoeboids
4. Excavates- unicellular flagellates
5. Plantae- rhodophyta, chlorophyta, seagrasses
6. Amoebozoans- slimemolds
7. Fungi- heterotrophs with extracellular digestion
8. Choanoflagellates- unicellular
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9. Animals- multicellular heterotrophs
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Algal Nomenclature- acknowledges the first and last
person to describe the species
1753, Linneaus divided all life into two Phyla =
Plants and Animals
for example: Linnaeus called this Fucus pyriferus; later
renamed Macrocystis pyrifera by Carl Adardh, so:
Within the plants, he recognized
• Cryptogams – hidden gametes…land plants
• Thallogams – unspecialized gametes … the algae
Only
l three
h
genera originally
ll recognized:
d
Macrocystis pyrifera (Linnaeus) Adardh
Fucus-fleshy
Ulva- membranous
Conferva- filamentous
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Division
% marine
~# species
-Taxonomy/systematics constantly under revision
- Depending on who you ask, between 50,000 and
10 million different algal spp!
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50
90
4,500
7,000
6,000
16,758
2,000
12,000
3 000
3,000
Bryophyta
Mosses, liverworts
0
25,000
-Morphology?
Vascular plants
Ferns, horsetail, club moss
Gymnosperms
Angiosperms
0.1
0
0.09
Cyanophyta (blue-green algae)
Rhodophyta (red algae)
Chlorophyta (green algae)
Ochrophyta
Phaeophyceae (brown algae)
Bacillario/Coscinodiscophyceae(diatoms)
Di
Dinophyta
h t (dinoflagellates)
(di fl ll t )
8
98
13
13,018
722
285,000
- Biological species concept?
- Genetics?
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Mastocarpus species complex
Petrocelis
Mastocarpus papillatus
2N ‘Petrocelis’ crust
(sporophyte)
+
2N
1N
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1N fronds
(gametophytes)
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Algal Evolution:
Endosymbiotic theory of organelle acquisition:
(L. Margolis)
3.9 bya = Cyanobacteria appear and introduce photosynthesis
2.5 bya = Eukaryotes appeared (nuclear envelope and ER thought to come
- Heterotrophic eukaryote eats
heterotrophic bacteria
(proteobacteria) lead to the
formation of mitochondria
from invagination of plasma membrane)
1.6 bya = Multicellular algae -Rhodophyta (Red algae) &Chlorophyta
(Green algae)
y Dinoflagellates
g
& Invertebrates appear
pp
900 mya=
-Heterotrophic
p
eukaryote
y
eats a
photosynthetic bacteria
(cyanobacteria) lead to the formation
of a chloroplast
490 mya = Phaeophyceae (Brown algae) & land plants & coralline algae &
crustaceans & mulluscs
408mya= Insects & Fish
-Bacteria not digested but becomes
an organelle
362 mya = Coccolithophores & Amphibians & Reptiles
290mya- Gymnosperms
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145 mya = Diatoms & Angiosperms
Secondary endosymbiotic events
Primary Endosymbiosis:
1.
Support of Endosymbiotic Theory
-Genetic material of the 2 membranes that surround the
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organelle
Heterotrophic eukaryote eats
photosynthetic bacteria
(cyanobacterium).
2. Results in photosynthetic eukaryote.
Chloroplast has 2 membranes
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1.
Heterotrophic eukaryote eats
photosynthetic eukaryote
2.
Nucleus from photosynthetic
eukaryote is lost
3.
Chloroplast ends up with 4
membranes
m
mb
s
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Secondary endosymbiotic events
Secondary Endosymbiosis:
1.
Heterotrophic eukaryote eats
photosynthetic eukaryote
1.
Heterotrophic eukaryote eats
photosynthetic eukaryote
2.
Nucleus from photosynthetic
eukaryote is lost
2.
Nucleus from photosynthetic
eukaryote is lost
3.
Chloroplast ends up with 4
membranes
m
mb
s
3.
Results in photosynthetic eukaryote.
Chloroplast
hl
l
has
h 4 membranes.
Tertiary endosymbiotic events
occur in dinoflagellates
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Details of Endosymbiotic origins
?
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- Loss
What is agreed upon:
• Each algal division is a
monophyletic group
• Reds and Greens – 1 event-2
membranes
• Browns – 2 events- 4
membranes
of plastids
e.g. Parasitic algae on seaweeds: no pigments, all white
Plocamiocolax = Parasite on Rhodophyte alga Plocamium
Plocamiocolax on Plocamium
Adapted From Palmer 2003
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Plocamium
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- Loss
Three main divisions (phyla) of seaweeds:
of plastids
Chlorophyta: green algae
e.g. Heterotrophic algae
1 endosymbiotic event = 2 plastid membranes
~1.6bya
~6,000 species, 13% marine
Toxoplasma gondii = parasite in mammal muscular tissues
- Apicomplexan, closely related to dinoflagellates
Ochrophyta: brown algae & diatoms
2 endosymbiotic events = 4 plastid membranes
~490 mya
~2,000, 99% marine & 12,000, 50%
Rhodophyta: red algae
~60% of domestic cats are infected;
toxoplasmosis in pregnant women… caused by an alga!
1 endosymbiotic event = 2 plastid membranes
~0.9 bya
~7,000, 98% marine
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Paper Discussion on thursday:
Lubchenco and Cubit. 1980.
Heteromorphic life histories of certain marine algae as
adaptations to variations in herbivory. Ecology 61(3): 676-687
Abstract
Introduction
Graphs & Figures
Methods
Results
Discussion
Sign up for paper you would like to lead.
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