Plantae...Plantae- rhodophyta, chlorophyta, seagrasses 6. Amoebozoans- slimemolds 7. Fungi- heterotrophs with extracellular digestion 8. Choanoflagellates- unicellular 9. Animals-

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Division: Chlorophyta(green algae)

I. General CharacteristicsII. MorphologyIII. Distinguishing ClassesIV. Classes in Detail

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~ 16,000 species~ 90% freshwater

Hierarchical system of classification:

Level: suffix: example:Domain EukaryoteGroup PlantaeDivision -phyta ChlorophytaClass -phyceae Ulvophyceae

II. Algal taxonomy

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p y p yOrder -ales UlvalesFamily -aceae UlvaceaeGenus Ulvaspecies fenestrata

DOMAIN1.Bacteria- cyanobacteria (blue green algae)2.Archae3.Eukaryotes

Groups (Kingdom)

1. Alveolates- dinoflagellates

2. Stramenopiles- diatoms, heterokonyophyta

3. Rhizaria- unicellular amoeboids

4 Excavates- unicellular flagellates

“Algae”

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4. Excavates- unicellular flagellates

5. Plantae- rhodophyta, chlorophyta, seagrasses

6. Amoebozoans- slimemolds

7. Fungi- heterotrophs with extracellular digestion

8. Choanoflagellates- unicellular

9. Animals- multicellular heterotrophs

Glaucophytes

Rhodophyta

Chlorophytes

Plantae

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Adapted from Sadava 2014

Charophytes

Land Plants

Chl b,starch

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Chlorophyceae

Trebouxiophyceae

Ulvophyceae

Phylogenetics of Chlorophyta (morphological, molecular data)

4 classes:

Chlorophyta

Chl b,starch

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Prasinophyceae

CharophytesCharophyceae

Land plants

a

Encasement of egg

Embryo, cuticle

I. General Green Characteristics:

1) Pigments: ?

2) Chloroplast structure?:

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3) Storage product?

4) Flagella?

Chlorophyceae = freshwater

Trebouxiophyceae = freshwater, soil and marine

Ulvophyceae = marine macroalgae

Classes:

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p y g

Prasinophyceae = primarily marine flagellates, some freshwater; modern representatives of earliest green algae

Charophyceae = freshwater; all terrestrial plants are derived from Charophycean class

II. MorphologyChlorophyta:easiest division to identify visually

• usually bright, grass-green color

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II. MorphologyChlorophyta:easiest division to identify visually

• usually bright, grass-green color

Except -

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Snow algae DunaliellaTrentepohlia parasitic on Monterey Cypress

photo: Morgan Bond

Charophyceans

For classes:- any easy “rules” using external thallus morphology?

- Prasinophyceans are all unicells, but…

10Chlorophyceae Ulvophyceae Ulvophyceae

“napkin ring-shaped parietal”

Diversity in chloroplast shape: (unique to algae)

“cup-shaped parietal”

“axial (plate-like)”

“stellate (star-shaped)”

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“reticulate (net-like)”

axial (plate like)

“multiple discoid”

“ribbon-like”

1. How flagella are attached/constructed:• basal bodies orientation• microtubule roots

III. Distinguishing among classes based on:

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2. Cell covering:• scales vs. cell wall

3. How cells divide: • aspects of mitosis and cytokinesis

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1. How flagella are attached/constructed:-basal bodies orientation-microtubule roots

Flagella

Basal Bodies


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anterior

swimming direction

Cell

Microtubule roots

Flagella- complex cellular projections used for movement- bundle of nine fused pairs of microtubule doubletssurrounding two central single microtubules "9+2"

Basal bodies- attachment site of the flagella- containing a microtubules 9 triplet configuration forming a hollow cylinder

Flagella

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Cell

Flagella

Basal Bodies

Microtubule roots

opposite parallel clockwise counterclockwise

Basal Bodies: ONE per flagellum, located at base of flagellum, anchoring into cell-pairs of basal bodies may be

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Cell

Flagella

Basal Bodies

Microtubule roots

Microtubule roots: -under the cell membrane at point of

attachment of basal bodies- may be cruciate or broadband Cell

Flagella

Basal Bodies

Microtubule roots

16cruciate broad-band

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2. Cell covering- scales vs. cell wallIII. Distinguishing among classes based on:

Scales are made of complex polysaccharides secreted from golgi Cell wall = usually cellulose

prasinophyceae Chlorophyceae, trebouxiophyceae,Ulvophyceae, charophyceae

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3. How cells divide: (aspects of mitosis and cytokinesis)

• open vs. closed mitotic spindle

• phycoplast vs. phragmoplast

• furrowing vs. cell plate formation in center of cell


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closed Open-during Mt nuclear envelope breaks down

metacentric centrioles






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Phragmoplast: double microtubules perpendicularto dividing plane-land plants

Phycoplast: microtubules parallel to dividing plane -rare in algae

furrowing furrowing






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furrowing = most algae cell plate formation = a few algae and land plants

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Some new terms:

Isogamy – sexual fusion between flagellated gametes that are similar in size and shape

Anisogamy – sexual fusion between flagellated gametes of distinctly different sizes

Oogamy – sexual fusion between a flagellated gamete(sp m) nd n n fl ll t d m t ( )

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(sperm) and non-flagellated gamete (egg)

Sporophyte: diploid, 2n, multicellular release spores in alternation of generations

Gametophyte: hapliod, 1n, multicellular release gametes in alternation of generations

Review:

Chlorophyceae

Trebouxiophyceae

Ulvophyceae

5 classes:

V. Classes in detail - Chlorophyte Diversity:

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Prasinophyceae

Charophyceae

Land plants

Class Chlorophyceae:

1. How flagella are attached/constructed:b s l b di s i t ti l k i

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• basal bodies orientation = clockwise• microtubule roots = cruciate

2. Cell covering:• scales vs. cell wall = wall

3. How cells divide: • spindle = closed• microtubule organization = phycoplast• division by = furrowing

Microtubule Roots: cruciateBasal Bodies: clockwise

Chlorophyceae

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Cell

Flagella

Basal Bodies

Microtubule roots

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Class Chlorophyceae:

7000+ spp

mostly freshwater

unicells, colonies, coenocytes, filaments,

haplontic life history- 1N thallus, the zygote is the only diploid stage, with “hypnozygote” = thick walled resting stage

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isogamous, anisogamous, and oogamous species

Genera:

Chlamydomonas, Volvox, Dunaliella

Order: Volvocales Genus: Chlamydomonas

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• Cup-shaped chloroplast, orange eyespot

• Scientists sequenced and mapped genome in 2003

• Used as a model to determine how gene expression works

• Use mutations to determine where genes are on chromosomes

Chlamydomonas life history:

Usually asexual

Mt

fluid conditions

moist but not wet conditions

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“palmelloid stage”

Haplontic- Sexual reproduction in unfavorable conditions

28Hypnozygote= resting stage(1/2) (1/2)

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Genus: Volvox

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• Spherical colonies of 500 – 40,000 cells

• Each colony contains a large number of somatic cells and a small number of reproductive cells

• Zygotes are orange

Volvox life history

• Oogamous

• Gonidia = specialized cells that divide to become daughter colonies

• Zoospore = spore with

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• Zoospore = spore with flagella

• Endospore = surrounds zoospore

• Mesospore = initially surrounds endospore + zoospore

Genus: Dunaliella

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• Common in salt ponds: have special ion pumps

• Packed with beta-carotene to protect from UV irradiance

• Commercial value (beta-carotene) = used for food coloring and in pharmaceuticals

Chlorophyceae

Trebouxiophyceae

Ulvophyceae

Chlorophyte Diversity

5 “classes”:

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Prasinophytes

Charophyceae

Land plants

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Class Ulvophyceae:

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1. How flagella are attached/constructed:• basal body orientation = counterclockwise• microtubule roots = cruciate

2. Cell covering:• scales vs. cell wall = wall (scales in some reproductive unicells)

3. How cells actually divide: • spindle = closed• microtubule organization = phragmoplast• division by = furrow

Microtubule Roots: cruciateBasal Bodies: counterclockwise

Ulvophyceae

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Cell

Flagella

Basal Bodies

Microtubule roots

Class Ulvophyceae:

Mostly marine macroalgae, some freshwater too

Haplontic, diplontic, or alternation of generations

No hypnozygotes

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Class Ulvophyceae:

Mostly marine macroalgae, some freshwater too

Haplontic, diplontic, or alternation of generations

No hypnozygotes

Orders to know:

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Orders to know:

• Ulotrichales/Ulvales

• Trentepohliales

• Cladophorales

• Bryopsidales

• Dasycladales

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Ulvophyceans have diverse morphologies

unbranched filament b h d fil t

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unbranched filament

parenchymatous coenocytic/siphonous

branched filament

Division: Chlorophyta

Class: Trebouxiophyceae ChlorophyceaeUlvophyceae Prasinophytes

Order:Ulvales Bryopsidales

CladophoralesUlotrichales Dasycladales

Trentepohliales

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- Unicells, filaments, blades; uninucleate or multinucleate cells

- Simple, haplontic life histories; all with an attached Codiolum stage formed by zygote; zygote undergoes meiosis, producing flagellated meiospores

Focal genera: Ulothrix

Order Ulotrichales – e.g. Ulothrix

Haplontic with codiolum phase-1N thallus, the zygote is the only diploid stage-Codiolum phase- cell wall is from 2N zygote with 1N spores inside

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syngamy

• Cell wall of zygote (2N) stays intact to

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1Ncodiolum

stage

meiosisoccurs

in zygote

2Nzygote

1N zoospores

1N gametophytes

1N gametes

(2N) stays intact to contain new meiospores (N)

•Codiolum stage –dormant until favorable conditions




CladophoralesUlotrichalesDasycladales

Trentepohliales

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- Uninucleate cells with a single parietal chloroplast - Parenchymatous thallus; mono- or distromatic, sheets or tubes- All cells can reproduce (holocarpic reproduction)- Isomorphic alternation of generations

Focal genera: Ulva

“sea lettuce”

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Order Ulvales e.g. Ulva

Isomorphic Alternation of Generations: organism having a separate multicellular diploid sporophyte and haploid gametophyte stage, sporophyte & gametophyte are same sizes

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Ulva spp• Distromatic• Often ephemeral in intertidal zone• Fast growing, tasty to herbivores• Green tides!

• Tubular• Euryhaline - tolerates freshwater, often occurs near seeps

Ulva intestinalis =

•Green tides!

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CladophoralesUlotrichalesDasycladales

Trentepohliales

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- Large, multinucleate cells, connected end to end with cross walls- Chloroplasts reticulate or multiple discoid arrayed in reticulate network- Isomorphic alternation of generations

Focal genera:

Cladophora, Chaetomorpha, Anadyomene

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Order Cladophorales e.g. Cladophora

Isomorphic Alternation of Generations: organism having a separate multicellular diploid sporophyte and haploid gametophyte stage, sporophyte & gametophyte are same sizes

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Japanese Cladophora spp: “marimo balls”

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• Size: up to 30 cm (formed by turbulent water + sediments)

• A folktale in which the hearts of a young couple who drown in a lake turn into Cladophora balls

• Meditation – watch balls rising and falling

• Protected species - three day festival to promote conservation

Temporate Cladophorales

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Cladophora Chaetomorpha

- “Pin cushion” alga

- Branched filamentous

- Harbors inverts Nutrients

- Unbranched filaments

- Modified basal cell w/rhizoidalextensions

Tropical Cladophorales

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Ventricaria

- Made up of single central cell (big) and lots of lateral cells (small)

Anadyomene

- Cells become progressively smaller toward periphery

-Small cells fill spaces between large-celled filaments (veins)

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Class:

Order:


Trebouxiophyceae ChlorophyceaeUlvophyceae Prasinophytes

Ulvales BryopsidalesCladophoralesUlotrichales

Dasycladales

Trentepohliales

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- Coencocytic/siphonous thallus construction

- Lots of variability in form (uniaxial, multiaxial, etc.)

- Mostly biflagellate anisogamous reproduction; various life histories

- Some calcified: major component of tropical sands remains of coralline greens form a layer >50 m thick at Great Barrier Reef

- Synchronous spawning in tropics

Focal genera:

Order Bryopsidales

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Halimeda CaulerpaCodium “dead man’s fingers”

Coenocytic/siphonous construction:

Multinucleate; no division of cytoplasm with cell walls

Morphology

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cytoplasm with cell walls

“clotting compounds” quickly repair wounds

Uniaxial and multiaxial construction

Morphology

52Bryopsis Codium “dead man’s fingers”

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Codium fragile

Utricles

Morphology

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Gametangium

Utricles: peripheral portions of siphons may be inflated & aggregated to form outer surface gametangia (reproductive structures)

Codium is ~ size of an apple =~30 km of siphons

Kleptoplastids

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(Sacoglossan opistobranchs are thieves!)

- Common in siphonous greens

- Sacoglossan radula adapted to host alga (length of tooth ~ thickness of siphon)

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- Pierce and suck out insides

- Stolen chloroplasts can last up to a month or so

Elysia

Codium fragile

Order Bryopsidales: e.g.Codium

Diplontic: 2N thallus, the gametes are the only haploid stage

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Codium and scallop interaction on East Coast

• Attach and grow on scallops

• Weigh them down and

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Weigh them down and prevent escape from predators

• Cast adrift in heavy storms

• Results in high mortality

Holocarpic reproduction in many tropical members of Bryopsidales

Halimeda

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- Anisogamous, dioecious = separate sexes- Entire thallus turns into gametes- Gametes migrate to surface overnight- Major contributor to tropical sediment

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- Thousands of individuals spawn synchronously

- Water visibility drops to ~ 1m downstream from reef, but disperses within ~1/2 hr

- Empty thallus disintegrates (often within hrs)

- In some species:

gametes positively phototactic

zygotes are negatively phototactic WHY??

- New tissue put on at night (why?)

- New segments not fully calcified, but heavily defended chemically

- Chloroplasts stay in older segments until minutes before sunrise

- Increase in calcification = decrease in chemical defenses

Tropical siphonous greens, timing of growth, and herbivory

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Caulerpa invasion

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• Native in southern Australia• 1st introduced as a non-native in Mediterranean• 2002: introduced at 2 sites in S. California large eradicationattempted

• Grows fast, large, asexual reproduction, and resistant to cold temps• Listed as one of the top 100 invasive species on earth

Caulerpa = uniaxial, but with trabeculae for support

trabeculae = ingrowths of wall material

Morphology

62Siphons form rhizoidal holdfast too

Class:

Order:




Dasycladales

Trentepohliales

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- Extensive fossil record, group is 500 myo with 11 extant genera - Tropical, shallow water spp- Unicellular thalli with one nucleus and radial symmetry

Celebrity genus: Acetabularia

“mermaid’s wine glass”

1930’s - Hammerling’s experiments with Acetabularia

64mRNA

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Class:

Order:




Dasycladales

Trentepohliales

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- All terrestrial (~40 spp)- Uninucleate, special urn-shaped gametangia, dispersed by wind?- Branched filaments, numerous discoid plastids, orange due to carotene containing lipid droplets (photoprotective?)- Often epiphytic/parasitic

Focal genus: Trentepohlia

- Often epiphytic/parasitic

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Chlorophyceae

Trebouxiophyceae

Ulvophyceae

5 classes:


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Prasinophyceae

Charophyceae

Land plants

Class Trebouxiophyceae:

1. How flagella are attached/constructed:b s l b di s i t ti t l k i

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• basal bodies orientation = counterclockwise• microtubule roots = cruciate


3. How cells actually divide: • spindle = closed; metacentric• microtubule organization = phycoplast • division by = furrow

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Microtubule Roots: cruciateBasal Bodies: counterclockwise

Trebouxiophyceae

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Cell

Flagella

Basal Bodies

Microtubule roots

Class Trebouxiophyceae:

mostly freshwater and terrestrial algae

unicells, filaments, blades

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Genera: Chlorella, Prasiola

Genus: Chlorella

- Unicellular

- Endosymbiont in freshwater animals

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- Endosymbiont in freshwater animals

- Single, cup-shaped chloroplast

- Used by Melvin Calvin to investigate carbon fixation in plants (Calvin cycle)

- Marketed as a dietary supplement

Genus:Prasiola

- Diplontic- 2N thallus, the gametes are the only haploid stage

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- Found in ultra-high intertidal (spray zone) in areas with highguano

- “Nitrophilic”

- Thalli small (< 2cm), monostromatic blades

- Individuals higher on shore produce asexual (2N) spores

- Individuals lower on shore produce gametes, oogamous

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Prasiola Life History

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Chlorophyceae

Trebouxiophyceae

Ulvophyceae

IV. Classes in detail - Chlorophyte Diversity:

5 classes:

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Prasinophyceae

Charophyceae

Land plants

Class Prasinophyceae:

1. How flagella are attached/constructed:b s l b di s i t ti i bl

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• basal bodies orientation = variable• microtubule roots = variable

2. Cell covering:• scales vs. cell wall = scales

3. How cells actually divide: • spindle = open or closed• microtubule organization = phragmoplast or phycoplast• division by = furrow

Microtubule Roots: cruciateBasal Bodies: opposite

Some Prasinophyceans

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Cell

Flagella

Basal Bodies

Microtubule roots

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Class Prasinophyceae Genus Tetraselmis

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modern representatives of ancestral green (most primitive)

unicellular flagellates

freshwater and marine

one plastid with one pyrenoid

mostly asexual

Chlorophyceae

Trebouxiophyceae

Ulvophyceae

5 classes:


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Prasinophyceae

Charophyceae

Land plants

Class Charophyceae:

1. How flagella are attached/constructed:b s l b di s i t ti ll l

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• basal bodies orientation = parallel• microtubule roots = broad band


3. How cells divide: • spindle = open• microtubule organization = phragmoplast• division by = furrow or plate

Microtubule Roots: broadbandBasal Bodies: parallel

Charophyceae

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Cell

Flagella

Basal Bodies

Microtubule roots

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Class Charophyceae:

most closely related to terrestrial plants

usually unicells or filaments, but sometimes colonies and more complex forms

Genera: Desmids, Chara

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freshwater

haplontic- 1N thallus, the zygote is the only diploid stage

oogamous reproduction

dormant zygotes

Algal Life Cycles

Haplontic- 1N thallus, the zygote is the only diploid stage

NMt fuse

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MeN

2Nzygote

1Nspores

grow

Class Charophyceae: Order ZygnematalesDesmids

• 2 semi-cells that are mirror images, nucleus is in center

• asexual reproduction = mitosis

• sexual conjugation = pairing between cells

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between cells

• movement through mucilage secretion

Class Charophyceae: Order Charales Genus Chara

Macroscopic

Freshwater

Can be partially calcified

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Central axis with whorls of branches at nodes

Often smell of garlic

Food and nursery habitat for waterfowl

Documents

Plantae...Plantae- rhodophyta, chlorophyta, seagrasses 6. Amoebozoans- slimemolds 7. Fungi- heterotrophs with extracellular digestion 8. Choanoflagellates- unicellular 9. Animals-