Lecture 19

Question 1

What is special about the Protista kingdom?

Answer 1

• an unnatural grouping, should be several kingdoms and only out of convenience aren’t
• some are protists more distantly related from one another than humans from fungi

Question 2

What defines the kingdom Protista?

Answer 2

Unnatural grouping
• Diverse and simple eukaryotic cell
types
Comprised of
: • Producers - several divisions of
photosynthetic algae
• Consumers - ciliates, colourless flagellates, parasites, pathagens
• Absorbers & Recyclers - slime moulds, water moulds
producers= have chloroplasts, photosynthetics like plants sort of
consumers= eat things like animals
absorbers recycles= like fungi on land sort of

Question 3

What is the importance of the age of slime?

Answer 3

when protists evolved= lasted that age for 3 billion years
-A long empire – lasting over 3 billion years. Microscopic assemblages of single-celled organisms (e.g., Bacteria (Cyanobacteria), Archaea and Protists) Microbial mats held
together by organic ‘glues’, creating the perfect habitat.
The evolution of hungry, primitive animals (metazoans) ended their dynasty about 500 million years ago. Few fossils, but mats survive today in harsh environments.
can still find the slime layers.
-changed because larger animals developed and ate it

Question 4

Why are the primary producers so colourful?

Answer 4

They posses diverse chloroplasts and pigments.

Question 5

What are macroalgae (seaweeds) important for?

Answer 5

-important primary producers

Question 6

What are the three divisions of seaweed?

Answer 6

Rhodophyta (red algae)
• Chlorophyta (green algae)
• Phaeophyta (brown algae)
• Each group has a different combination of pigments and a range of other features that distinguish them.

Question 7

Where did the green, red and brown algae get their chloroplasts?

Answer 7

red and green= primary endosymbiosis

brown- secondary (protistan pirate)

Question 8

Why can there be 4 membranes in protistan pirates?

Answer 8

first two from cyanobacteria, thrid= cell membrane of the eukaryote with the chloroplast, 4th= sometimes, so food vacuoles so 3 or 4 membranes

Question 9

Why is red algae important?

Answer 9

Commercially harvested for agars and carrageenans for science and the food industry.
-gels for molecular biology and biochemistry
-thickening and stabilising agents for the food industry
-big and up and coming industry
-agarose!-the key= not in all red algae
-30% of red algae= in Australia, 70% only found here
toothpaste= has red algae product
-cosmetics too

Question 10

What does the colour of red algae depend on?

Answer 10

• depends on the concentration of Chlorophyll A, plus phycoerythrin and phycocyanin
• red algae can look brown or green, can get range of colour so it depends on accessory pigments as well

Question 11

What were the ancestors of land plants?

Answer 11

green algae

Question 12

What chlorophyl do green algae have?

Answer 12

Chloroplastsaregreen- (chlorophylls A , B) and are primary endosymbionts.

Question 13

What are green algae used for commercially?

Answer 13

• major biofoulers &
  polluters. - solar energy, biofuels
• grow really quickly

Question 14

What are brown algae?

Answer 14

• Marine seaweeds
• Protistan pirates -
chloroplast from a red alga and contains Chl A + C and the brown pigment fucoxanthin.
• Cell walls contain a major source of commercially important alginates used in the food industry (e.g. kelp farming)

Question 15

How do seaweed have sex?

Answer 15

tied into the lunar cycle- moon comes up= release sperm, eggs= sperm goes up to light
then eggs drop down

Question 16

What is interesting about diatoms (Bacillariophyta)?

Answer 16

• Unicellular and major primary producers in all aquatic habitats.
• Protistan pirates - chloroplast from a red alga and contains Chl A + C and the brown pigment fucoxanthin.
• Highly ornate cell walls made of silica (glass!).
• Some diatom species can adhere to the substratum and “glide” over it.

Question 17

How are diatoms interesting commercially?

Answer 17

• Some species are major biofoulers of boat bottoms and other man- made surfaces in marine habitats.
• Biological processes involved in the nanofabrication of hard, 3-dimensional structures of silica is of great interest to materials science.

-diatomaceous earth- 2 miles thick remains of diatoms= used in filters in pools and in toothpaste, cosmetics

Question 18

What problem do diatoms cause to ships?

Answer 18

-create layer of diatoms= slime and that sticks to the hull of the ship, 5cm thick one= increase 20% of fuel cost= hard to get rid of!

Question 19

Which class is an animal-like producer or mixotroph?

Answer 19

Dinoflagellates and Coccolithophorids.

Question 20

What are mixotrophic protists?

Answer 20

-protistan pirates that posses both chloroplast for photosynthesis(i.e.producers) and also ingest things by phagotrophy using complex mechanism of prey capture (consumers)

Question 21

What are Dinoflagellates (Dinophyta)?

Answer 21

• Diverse protistan pirates - have undergone secondary endosymbiosis several times, and pigments therefore vary between different species.
• Responsible for toxic “red tides” & fish kills, and bioluminescence
-some ate brown algae, some green, some red (secondary endosymbiosis)and some cryptomonads= tertiary endosymbiosis
-some parasitic

Question 22

What is the connection of Dinoflagellates and corals?

Answer 22

-zooxanthellae are symbionts in corals and some other animals= provide sugars for the corals