Lectures: SAR

Question 1

Stramenopila:

Answer 1

• At some point in life cycle, all have flagella that are covered with distinctive, hollow ‘hairs’
• Unicellular and multicellular forms
• Includes brown algae, water molds, and diatoms

Question 2

Plankton

Answer 2

diverse group of mostly microscopic organisms that drift in marine and freshwater systems and serve as a food source for larger aquatic organisms

Question 3

Diatoms:

Answer 3

• Major component of plankton
• Most important primary producers in
  freshwater and marine ecosystems
  – Extremely abundant
  – 20-25% of all carbon fixation!
  – Those not consumed sink to ocean floor; carbon not returned to atmosphere
• Wide variety of shapes with glassy cell walls

Question 4

Brown algae:

Answer 4

• Multicellular
• Includes many ”seaweeds” and kelp
  (e.g. Kelp “forests”
  a) foundation species
  b) support diverse communities
  c) important producers
• Some have specialized tissues that resemble plants
  (e.g. Holdfasts (roots), stipes (stems), blades (leaves))

Question 5

Alveolata:

Answer 5

• Unicellular
• Alveolus, which provides support for the cell
• Includes dinoflagellates and ciliates

Question 6

Alveolus

Answer 6

flattened, membrane-bound vesicles packed into a continuous layer supporting the cell plasma membrane

Question 7

Dinoflagellates:

Answer 7

• Unicellular
• More species marine than freshwater
• Another important component of plankton
• Some species are capable of bioluminescent
• Few species are responsible for for harmful algae blooms (“red tide”)

Question 8

Ciliates:

Answer 8

• Unicellular
• Covered in Cilia, which is used to swim
• 2 distinct nuclei:
  a) Micronucleus: sexual reproduction
  b) Macronucleus: asexual reproduction
• Contractile Vacuole

Question 9

Contractile Vacuole

Answer 9

vesicle that fills with water (as it enters the cell by osmosis) and then contracts to squeeze water from the cell; an osmoregulatory vesicle

Question 10

Rhizaria:

Answer 10

• Single-celled
• Lack cell walls
• Vary widely in form but most are amoeba-like
• Move by amoeboid motion with long slender pseudopodia

Question 11

Foraminiferans:

Answer 11

• Best studied Rhizaria
• Foramin = “hole”
• Tests, holes through which the pseudopodia protrude
• Abundant marine plankton, found at deep benthic zones

Question 12

Tests

Answer 12

porous shell of a form that is built from various organic materials and typically hardened with calcium carbonate

Question 13

What traits differ Stramenopila?

Answer 13

8: Stramenopila
(includes diatoms, brown algae):
* Hairy flagella

Question 14

What traits differ Alveolata?

Answer 14

8: Alveolata
(includes dinoflagellates, ciliates):
* Sac-like alveolus under plasma
membrane

Question 15

What traits differ Rhizaria?

Answer 15

10: Rhizaria
(includes foraminiferans):
* Tests
* Amoeboid motion with slender
pseudopodia