Transcript Sep 27 - University of San Diego

I.
Archaea
•
Resemble bacteria superficially but may be
more closely related to eukaryotes than
bacteria
•
•
•
May be heterotrophs or autotrophs
•
Methanogens
•
Nitrogen fixers
Important decomposers
•
Abundant in sediments
Extremophiles
•
Sulfur rich hot springs
•
Acid/Alkaline lakes (acidophiles)
•
Hydrothermal vents (thermophiles)
•
Deep sea (barophiles)
•
Antarctic (psychrophiles)
II. Unicellular Algae
A.
Eukaryotes
•
•
B.
Fig. 4.8b
Diatoms (Bacillariophyta)
•
•
Fig. 15.3a
Photosynthesis in chloroplasts
Lack flowers, stems, leaves, roots
•
•
Unicellular
•
May form chains
Cell enclosed by silica (SiO2) frustules (test)
•
Test usually perforated and ornamented with
spines or ribs (Why?)
Perforations allow gases, nutrients, waste products to
pass through test to cell
Important open-water primary producers, especially in
temperate and polar regions
Fig. 5.5
II. Unicellular Algae
B.
Diatoms (Bacillariophyta)
•
Reproduction
•
Asexual - Cell division
•
Sexual - Egg + Sperm --> Auxospore
Fig. 5.6
II. Unicellular Algae
B.
Diatoms (Bacillariophyta)
•
•
•
Reproduction
Explosive population growth --> Bloom
•
May deplete nutrients locally
Sediments beneath areas where diatoms are abundant
may contain many tests
•
Diatomaceous oozes
•
Diatomaceous earth
II. Unicellular Algae
C.
Dinoflagellates (Dinoflagellata/Pyrrophyta)
•
•
Possess two flagella
•
Motile
Covered with theca made of cellulose plates
•
Theca may have spines
Fig. 5.7a
II. Unicellular Algae
C.
Dinoflagellates (Dinoflagellata/Pyrrophyta)
•
•
•
•
•
Possess two flagella
•
Motile
Covered with theca made of cellulose plates
•
Theca may have spines
Important open-water primary producers, especially in
tropical regions
Trophically diverse
•
Autotrophic
•
Heterotrophic
•
Mixotrophic
May bloom like diatoms
•
Red tides
•
Brown tides
http://www.whoi.edu/redtide/
II. Unicellular Algae
C.
Dinoflagellates (Dinoflagellata/Pyrrophyta)
•
•
Some forms live symbiotically with corals, anemones,
jellyfish, giant clams, sponges
•
Zooxanthellae
•
Lose flagella
•
Especially important in reef building corals
Some forms can be extremely toxic
•
Pfiesteria
- Blooms triggered by coastal pollution
- Toxin can cause memory loss in humans
II. Unicellular Algae
D.
Other Algae
1.
Silicoflagellates (Chrysophyta)
•
Silica test, usually with spines
Fig. 5.8
•
Single flagellum
2. Coccolithophorids (Haptophyta)
•
Covered by calcium carbonate coccoliths
•
Coccoliths may be important components of
sediments
3. Cryptomonads (Cryptophyta)
•
Lack skeleton
•
Two flagella
Fig. 5.9
III. Protozoa
A.
Foraminiferans
•
•
•
•
•
Test (shell) made of calcium carbonate (CaCO3) or
agglutinated sediment particles
•
Fossil tests used to age geological deposits
May have multiple chambers
•
Tests increase in size as organism grows
Feed by extending pseudopodia through pores in test
•
Trap bacteria and other small organisms/detritus
Pelagic forms (calcareous)
•
Often have spines
•
Tests may form foraminiferan oozes, esp. in shallow
water beneath tropics (white cliffs of Dover – England)
Benthic forms (calcareous or agglutinated)
•
Calcareous tests can be important sources of sand for
beaches
http://earthguide.ucsd.edu/earthguide/imagelibrary/orbulinauniversa.html
http://www.ucl.ac.uk/GeolSci/micropal/foram.html
III. Protozoa
B.
Radiolarians
•
•
•
C.
Test made of silica (SiO2)
Tests may form radiolarian oozes, esp. in deep water in
temperate and polar regions
Feed by extending pseudopodia through pores in test
•
Trap diatoms and other small organisms/detritus (Why
diatoms?)
Ciliates (Ciliophora)
•
•
•
Use cilia
•
Locomotion
•
Feeding
Free living
•
Pelagic (Tintinnids)
- Lorica
•
Benthic
Parasitic
http://rmbr.nus.edu.sg/research/terrestrial/fungi.htm
IV. Fungi
•
Unicellular or multicellular
•
•
Mostly microscopic
Heterotrophic
•
•
•
Important decomposers
•
Especially in mangrove forests
Some disease causing forms
Host to algae in lichens
V.
Multicellular Algae - Seaweeds
•
Macroalgae
•
A.
Complex but lack specialized structures of true plants
General Structure
•
•
Body = thallus
Flattened portion = blade
•
•
•
•
•
Not true leaves
•
No veins
•
Upper and lower surfaces identical
•
No tissues for transport of water, nutrients & minerals
Increase surface area (Why?)
Main sites of photosynthesis
Float = pneumatocyst
Anchor = holdfast
•
Do not penetrate sediment or absorb water & nutrients
Fig. 6.1