Transcript Protists 2 - Think. Biologically

Protists 2
Laboratory 4
BIOL 171
Note: The PowerPoint in lab will be abridged so you have more time. Please take a
few minutes to read this thoroughly. Thanks!
Lab Study E: Amoebozoans
Amoeba proteus
• Pseudopodia – temporary extensions of
amoeboid cells, function in moving and
engulfing food
Slime Molds (Mycetozoa)
• Protists which use spores to reproduce
• Heterotrophic – requires carbon in
organic form, cannot manufacture it’s
own
• Feed using phagocytosis
• Suggests they descended from unicellular
amoeba-like organisms
• Two types: plasmodial and cellular (we
will be observing plasmodial type today)
Physarum (slime mold)
• Plasmodial stage – vegetative stage that consists of a
multinucleate mass of protoplasm (no cell walls), feeds on
bacteria as it creeps along the surface of moist logs or dead
leaves
• Fruiting bodies – reproductive structures that produce spores
Physarum (plasmodial stage)
Is slime mold smarter than Japan's
railway engineers? check it out!
Slime Mold Life Cycle
Psychedelic slime mold video:
What is red algae?
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Eukaryotic
Photosynthetic
NOT plants
Most are aquatic
Lab Study F: Red Algae (Rhodophyta)
• Simplest is single celled, but most have a macroscopic,
multicellular body form
• Autotrophic (photosynthetic)– manufactures its own organic
nutrients from inorganic carbon sources
• Contain chlorophyll a and accessory pigments phycocyanin
and phycoerythrin
• Not all are red! Many green, black, even blue, depending on
the depth in the ocean they grow
Living Specimens
Porphyridium
Preserved specimens
Porphyra
coralline algae
Chondrus crispus
Porphyra life cycle
both sexual and asexual – alternation of generations!
Coralline algae – “living rock”
• Extremely important role in the ecology of coral
reefs: sea urchins, fish, and mollusks eat them
(herbivore enhancement).
• Create microhabitats that protect invertebrates
from predation.
• Cell walls composed of calcium carbonate – this
allows it to fossilize
• Economic importance: soil conditioners, food
additive for livestock, water filtration, medical
vermifuge (stopped late in 18th century),
preparation of dental bone implants
Economic Uses
• Agar – polysaccharide extracted from the cell
wall of red algae, used to grow bacteria and
fungi
• Carrageenan – extracted from red algae cell
walls, used to give the texture of thickness
and richness to foods such as dairy drinks and
soups.
• Porphyra (or nori) – seaweed wrappers for
sushi, billion-dollar industry!
Lab Study G: Green Algae (Chlorophyta)
• unicellular motile and non-motile, colonial,
filamentous, and multicellular – GREAT
DIVERSITY
• Live primarily in freshwater
• Share many characteristics with land plants
– Storage of starch, presence of chlorophylls
a and b, photosynthetic pathways, and
organic compounds called flavonoids
• Most botanists support the hypothesis that
plants evolved from green algae
Living Specimens
Chlamydomonas
Volvox
Pediastrum
Closterium
Pandorina
Volvox
Preserved Specimens
Ulva
Chara
Table 4: Representative Green Algae (pg. 72)
Name
Body Form
Spirogyra
Filamentous
Ulva
Leaf like
Chara
Branched
Chlamydomonas
Pandorina
Unicellular flagellate
Aggregate
Volvox
Colony (flagellate)
Pediastrum
Non-motile colony
Closterium
Non-motile single celled
Characteristics
Start filling out Table 5
• Comparison of protists studied last week and
this week