SLIMY SEX

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SLIMY SEX

• The Sequel

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OBJECTIVES

• Be able to describe the main definitive
  characteristics of the different taxa, especially
  the green algae and the blue-green algae
• Be able to describe the basic types of life
  cycles found in green algae and to recognize the
  reproductive structures in some commonly studied
  genera.
• Be able to explain the main classification
  debates for algae, including the red and brown
  and diatoms.
• Be able to recognize a few common and distinctive
  taxa Live specimens are more important than
  stained and preserved slides.
• Be able to discuss some details of the economic,
  evolutionary, and ecological importance of all
  these critters.

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most important objective

• Be able to describe the main definitive
  characteristics of the different taxa, especially
  the green algae and the blue-green algae

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• Blue-greenalgae are really bacteriabecause
  theircells have
• no nuclei
• no chloroplasts
• no mitochondria
• no true sex or mitosis or meiosis
• They are autotrophic (photosynthetic)
• They can fix nitrogen

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• Blue-green algae
• Cyanobacteria Cyanophyta
• slimy capsule gt inedible gt mat-forming scum
  gt environment problem
• out-compete edible algae which could feed
  protozoa etc.

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• Green algae are Good
• eukaryotic
• chloroplasts
• edible
• sexual
• filamentous --gtor unicellularor with a thallus

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• lt--Spirogyra is theclassic alga we like
  best(know its genus name, Spirogyra)

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Ulva sea lettuce (U of Wisc slide)
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Chara (U of Wisc slide)

• Stonewort
• freshwater

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• Chara
• has a 3-D
• multicellular
• thallus like a
• seaweed.
• Charas
• sexual parts
• are protected (more later).
• Chara is the evolutionary linkto land plants
  (more later)

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• DIATOMS andall the other golden-coloredalgae
  areChrysophyta or (for 21st-century
  cladists)Stramenopiles

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• a diatom---gt
• (golden) with silica (glass) shell
• The golden, brown, and red algae are
  evolutionary dead-ends.
• But they are autotrophic and often ecologically
  critical

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Volvox (U Wisc slide)
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• Isogamousor oogamous?

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OBJECTIVES

• Be able to describe the main definitive
  characteristics of the different taxa, especially
  the green algae and the blue-green algae
• Be able to describe the basic types of life
  cycle found in most green algae and to recognize
  the reproductive structures in some commonly
  studied genera.
• Be able to explain the main classification
  debates for algae, including the red and brown
  and diatoms.
• Be able to recognize a few common and distinctive
  taxa Live specimens are more important than
  stained and preserved slides.
• Be able to discuss some details of the economic,
  evolutionary, and ecological importance of all
  these critters.

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20th-Century CLASSIFICATION OF ALGAE.

• Chlorophyta (green),
• Chrysophyta (yellow),
• Rhodophyta (red),
• Phaeophyta (brown),
• sometimes Cyanophyta (blue-green) not
  eukaryotic,
• sometimes the problem groups (like protozoa)
• You need to remember because we still ID with
  20th-century keys

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21st-Century Classification of Algae

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The green algae Chlorophyta are closely related
to higher plants, but not to other eukaryotic
algae (except Charophytes)

• Green algae (and Charophytes) and the higher
  plants but not other algae all
• 1 have cellulose cell walls
• 2 store their extra sugar in a starch form.
• 3 have chlorophylls "a" and "b" but not "c"
• 4 except for primitive and strange algae have
  a life cycle type called alternation of
  generation,
  which we will study in all the land plants
  (everything else this year).

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Chara

• The hypothetical ancestor of higher plants
  mosses, ferns, angiosperms, etc. was a
  now-extinct green alga closely resembling the
  genus Chara. Other algae taxa are evolutionary
  dead ends, but they are still important
  ecologically and economically.

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21st-Century Classification of Algae

• GREEN PLANTS http//TOL or http//www.ucmp.berkele
  y.edu/alllife/eukaryotasy.html
• Chlorophyceae
• Trebouxiophyceae
• Ulvophyceae
• Streptophyta, including
• Zygnematales (Spirogyra and its friends),
• Charales
• - Embryophytes (land
  plants).

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• Tree of Life is not even trying to conform
  to the rules of the International Code of
  Botanical Nomenclature. Theyre just arranging
  things into clades which make some sense of the
  fine print in the old textbooks when the fine
  print didnt match the taxonomic ranks anyway.
• You JV botanists need to know 20th-century
  systematics for ID-ing, and 21st-century
  arguments to avoid being ambushed by future
  classification systems.

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OBJECTIVES

• Be able to describe the main definitive
  characteristics of the different taxa, especially
  the green algae and the blue-green algae
• Be able to describe the basic types of life
  cycles found in green algae and to recognize the
  reproductive structures in some commonly studied
  genera.
• Be able to explain the main classification
  debates for algae, including the red and brown
  and diatoms.
• Be able to recognize a few common and distinctive
  taxa Live specimens are more important than
  stained and preserved slides.
• Be able to discuss some details of the economic,
  evolutionary, and ecological importance of all
  these critters.

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BE ABLE TO DISCUSS

• The "symbiotic origin of eukaryotes
• The Tree of Life cladistics described in the
  previous pages concludes that the eukaryotic
  algae belong in at least three different
  subsubkingdoms. Beyond the DNA differences which
  are most important in phylogenetic revisions,
  other differences are in ultrastructure
  (especially in mitochondria and flagella and
  centrioles), appearances, pigments, chlorophylls,
  storage carbohydrates, other chemicals, whether
  they furrow or form cell plates after mitosis,
  and other distinctions. ...

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Pigments

• Pigments are important for ecology and
  biochemistry and 20th-century classifications.
• you should know that water absorbs many
  wavelengths of sunlight the reason that
  vegetative algal structures have so many strange
  colors is that these are the pigments which can
  scarf up the wavelengths that are left over
  beneath several centimeters of water. This is
  the same principle which explains why non-green
  leaves are more common in understory plants,
  especially in the tropics. The red and brown and
  purple leaves and algae are merely picking up
  stray wavelengths and then transferring the
  energy to chlorophyll.

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BE ABLE TO DISCUSS

• Prokaryotic blue-green algae are bacteria
• All algae must always live in water (except for
  quiescent spores) because they have no tissues
  specialized to keep them from drying out.
  Without water, algal syngamy is impossible, and
  gametes and embryos have no protection from
  drying.
• Algae can be unicellular, colonial, or
  multicellular and either motile flagellated or
  non-motile but bouyant for floating near the
  surface where light is strong enough for
  photosynthesis. The motile algae usually swim
  toward the light, but at night they may swim
  toward sediments where fertilizer is richer and
  predators are rarer.

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And, of course, be able to describe in detail
their slimy life cycles