Phaeophyta - the brown algae

Question 1

What type of algae are the phaeophyta

Answer 1

brown algae - they make up one of the most productive ecosystems (kelp forests)

Question 2

What type of water do the phaeophyta live in (brown algae)

Answer 2

almost exclusively marine
- unlike red algae more adapted to colder temperatures

Question 3

What is the hypothesized ancestor of phaeophyta

Answer 3

• flagellated ancestor
• xanthophytes –> chl a, chl c, and fucoxanthin

Question 4

What is the storage product of phaeophyta

Answer 4

laminarin

Question 5

Describe the cell walls of phaeophyta

Answer 5

their cell walls consist of slimy alginic acids and glue like fucans and some cellulose (they have a more pronounced outer cell wall)

Question 6

What is the anti herbivore defense in phaeophyta

Answer 6

• physodes excrete bitter tannins (chemicals that burst via grazers releasing acid into the mouths of whatever is trying to eat them)

Question 7

Describe the life history of phaeophyta

Answer 7

• early groups displayed isomorphic alternation of generations (gametic and sporophytic stages look interchangeable)
• later groups show heteromorphic alternation of generations

–> there has been a recent loss of the saprophytic stage resulting in the absence of alternation of generations in some groups

Question 8

What are the ectocarpales

Answer 8

these are small filamentous brown algae you can see true branching in these

Question 9

What is the life history of ectocarpales

Answer 9

• filamentous brown algae
• they have isomorphic biphasic life history
• they can also do parthenogenetic production of clonal zoospores by sporophytes (can produce asexually)

Question 10

describe the life history of laminariales

Answer 10

• brown algae kelp
• they have a heteromorphic biphasic life history
• dominated by the large sporophyte stage

Question 11

Describe the anchoring, floatation, and conduction in kelp (brown algae)

Answer 11

• they have a network of sieve elements in the blade?
• they have a holdfast medulla w/ no sieve elements at the bottom??

Question 12

Describe the fucales species

Answer 12

• these are brown algae that live in the fucoid zone
• they are perennial sporophytes
• they have a monophasic life history ((alternation of generations is pretty much lost, there is no multicellular haploid generation)