Today:Today:•Comments from our tour?

•Fungal Review

•Meeting the Algae

A Quick ReviewA Quick Review

Use your whiteboard to draw and define the following key terms:

ZygosporeAscus

BasidiumConidia

HeterokaryoticArbuscular Mycorrhizae

Why Algae?Why Algae? Primary Productivity!Primary Productivity!

This picture shows the distribution of the global yearly net fixation of carbon (g carbon per

square meter and year). Source: Science 281 (1998) pp 237-240. 

•Ancestors to Land Plants

(Understanding evolution!)

•Commercial products

•Inherent complexity and

beauty

Why Algae?Why Algae?

Back to the AlgaeBack to the Algae

General Characteristics:General Characteristics: PhotosyntheticPhotosynthetic members of the members of the

Stramenopila (water molds!)Stramenopila (water molds!) Named after the Named after the two different types two different types

of flagellaof flagella characteristic of the group characteristic of the group Plastids in this group most likely Plastids in this group most likely

evolved by evolved by secondary secondary endosymbiosisendosymbiosis

1. The Heterokont Algae1. The Heterokont Algae

Heterokonts: Note the single, long “hairy” flagella and the shorter, smoother flagella.Photo: © Peter v. Sengbusch

Unique glass-like Unique glass-like walls (silica walls (silica embedded in an embedded in an organic matrix)organic matrix)

1. The Heterokont Algae- Diatoms1. The Heterokont Algae- Diatoms

Life in a glass house! Diatoms are

responsible for ~25% of global photosynthesis!

Source: http://people.westminstercollege.edu/faculty/tharrison/emigration/diatoms.htmSource: http://people.westminstercollege.edu/faculty/tharrison/emigration/diatoms.htm

1. The Heterokont Algae- Diatoms1. The Heterokont Algae- Diatoms

More than one way to look at a diatom. This More than one way to look at a diatom. This picture shows the side view (top left) and top picture shows the side view (top left) and top view (bottom right) of a view (bottom right) of a Navicula lanceolataNavicula lanceolata

Usually Usually reproduce reproduce asexuallyasexually

May form May form resistant resistant cystscysts

Sexual Sexual stages rare! stages rare! (size (size dependent!)dependent!)

1. The Heterokont Algae- 1. The Heterokont Algae- DiatomsDiatoms

Use a glucose polymer, Use a glucose polymer, laminarin, to store food laminarin, to store food reservesreserves

Major component of Major component of diatomaceous earthdiatomaceous earth

1. The Heterokont Algae- Diatoms1. The Heterokont Algae- Diatoms

An Interesting Application of An Interesting Application of Diatom Biology…Diatom Biology…

http://www.pbs.org/wnet/nature/episodes/crime-scene-http://www.pbs.org/wnet/nature/episodes/crime-scene-creatures/video-diatom-detective/5208/creatures/video-diatom-detective/5208/

Named for their color (from Named for their color (from carotene and xanthophyll carotene and xanthophyll accessory pigments)accessory pigments)

Typically biflagellated and Typically biflagellated and unicellularunicellular

May be mixotrophic May be mixotrophic (absorption/ingestion in (absorption/ingestion in addition to photosynthesis)addition to photosynthesis)

1.1. The Heterokont Algae- Golden The Heterokont Algae- Golden Algae (Chrysophytes)Algae (Chrysophytes)

Prymnesium parvum, the golden alga

responsible for many fresh water fish kills.

Photo: Dr. Carmelo TomasU. of North Carolina, Wilmington

Macroalgae: A Sneak PreviewMacroalgae: A Sneak Preview

Multicellular, primarily Multicellular, primarily marinemarine

Largest and most Largest and most complex of all algae complex of all algae (“seaweed”)(“seaweed”)

Complex anatomy Complex anatomy evolved evolved independentlyindependently of of plants (analogous, not plants (analogous, not homologous)homologous)

1.1. The Heterokont Algae- The Heterokont Algae- Brown Algae (Phaeophyta)Brown Algae (Phaeophyta)

Anatomy of Anatomy of the Brown the Brown

Algae Algae (Phaeophyta)(Phaeophyta)

Blade

Stipe

Holdfast

Pneumatocyst

The body of a seaweed is called a thallus

The The Heterokont Heterokont

Algae- Brown Algae- Brown Algae Algae

(Phaeophyta): (Phaeophyta): Life Cycle Life Cycle

Note the heteromorphic generations!

2. The Red Algae 2. The Red Algae (Rhodophyta)(Rhodophyta)

No flagellated stages!No flagellated stages! Usually red colored Usually red colored

because of an because of an accessory pigment, accessory pigment, phycoerythrin (similar phycoerythrin (similar to those in to those in cyanobacteria!)cyanobacteria!)

Plastids of red algae Plastids of red algae most likely evolved most likely evolved from cyanobacteria by from cyanobacteria by primary endosymbiosisprimary endosymbiosis

Mostly marine (Mostly marine (deep! deep! Why?Why?), but may be ), but may be freshwater, or even in freshwater, or even in moist soilsmoist soils

Mostly multicellularMostly multicellular Complex life cycles; Complex life cycles;

dependent on water dependent on water currents to bring gametes currents to bring gametes togethertogether

2. The Red Algae 2. The Red Algae (Rhodophyta)(Rhodophyta)

The Green Algae The Green Algae (Chlorophytes)(Chlorophytes)

3. The Green Algae (Chlorophyta)

Unicellular, colonial, or Unicellular, colonial, or multicellularmulticellular

Primarily freshwater, Primarily freshwater, but also marine, in but also marine, in soils, and symbiotic soils, and symbiotic relationships (lichens!)relationships (lichens!)

Share a common Share a common ancestor with land ancestor with land plants!plants! The Unicellular green

algae, Chlamydomonas

3. The Green Algae (Chlorophyta)

Isogamy!

Mechanisms for the evolution of size and complexity:Mechanisms for the evolution of size and complexity:

1.1. Formation of Formation of coloniescolonies of individual cells ( of individual cells (VolvoxVolvox))

2.2. Repeated division of nuclei without cytoplasmic Repeated division of nuclei without cytoplasmic division (division (multinucleate filamentsmultinucleate filaments))

3.3. Formation of true multicellular forms by Formation of true multicellular forms by cell cell division and differentiationdivision and differentiation ( (UlvaUlva))

3. The Green Algae (Chlorophyta)

Life Cycle Life Cycle of the of the Green Green Alga, Alga, UlvaUlva

Note the isomorphic generations

!

Let’s Watch!Let’s Watch!

http://www.pbs.org/wgbh/nova/tech/algae-fuel.html