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Division: Rhodophyta

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

Groups (Kingdom)

1. Alveolates- dinoflagellates

2. Stramenopiles- diatoms, Ochrophyta

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

Unicellular, freshwaterChloroplast peptidoglycan

phycoerythrin

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Adapted from Sadava 2014

Charophytes

Land PlantsChl b,starch

Algal Evolution:

3.9 bya = Cyanobacteria appear and introduce photosynthesis

2.5 bya = Eukaryotes appeared (nuclear envelope and ER thought to come from invagination of plasma membrane)

1.6 bya = Multicellular algae -Rhodophyta (Red algae) &Chlorophyta (Green algae)

900 mya= Dinoflagellates & Invertebrates appeary g pp

490 mya = Phaeophyceae (Brown algae) & land plants & coralline algae & crustaceans & mulluscs

408mya= Insects & Fish

362 mya = Coccolithophores & Amphibians & Reptiles

290mya- Gymnosperms

145 mya = Diatoms & Angiosperms

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Division Rhodophyta

- most speciose of the macroalgae

Location S. Australia N. Atlantic W.USARed 800 (70%) 589 (50%) 459 (69%)Brown 231 324 137Green 123 258 72

1154 1171 668

7,117 species identified(up to 20,000 ?!?)98% marine

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Biogeography/distribution

• Found at all latitudes

•Tropical- small & filamentous

• Temperate highest # of spp (outnumber browns and greens)

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• Polar relatively few species – browns and greens dominate lots of crustose coralline reds, to 200 m

• Size distribution tropical = mostly small filamentous plants (except calcareous forms) temperate = larger fleshy species

1) Pigments: chl a & dcarotenoids: B-carotene, A-carotene

phycobilins: phycocyanin, phycoerytrin, allophycocyanin

2) Plastid structure: • envelope: 2• thylakoids: single, no stacks, covered with phycobilisomes

Rhodophyta Characteristics

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3) Storage product: floridian starch, doesn’t stain with IKI

4) Flagella: none

5) Life History: Alternation of Generations OnlyMitosis: closed, no centrioles

Hierarchical system of classification:

Level: suffix: example:Domain EukaryoteGroup PlantaeDivision -phyta RhodophytaClass -phyceae Florideophyceae

Algal taxonomy

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p y p ySubclass -phycidae RhodymeniophycidaeOrder -ales Rhodymeniales

Family -aceae RhodymeniaceaeGenus Rhodymenia

species pacifica

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Phycobilisome structure:

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Pigments

Allophycocyanin

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Structure of phycoerythrin + protein

Phycobilisome on the thylakoid membrane

…vs. other divisions: pigments imbedded within the thylakoid membrane

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Reds respond to changing light conditions by:

1. Changing the number/density of phycobilisomes

2. Changing the # of molecules of pigment in each antennae

Rhodophyta Pigments

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g g p g

…what is this called?

Buoy

Pigments Experiment: - same species of red algae- place on rope at 3 depths

Red light

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Green light

Buoy

PC

Pigments Experiment: - same species of red algae- place on rope at 3 depths

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PE

Two Main Components:

1. Cellulose microfibrils for structural support

2. Phycocolliods- Mucilaginous polysaccharides that surround microfibrils (more abundant than microfibrils)

Rhodophyta: Morphology of Cell Walls(Extracellular Matrix or ECM – less rigid than other

algae/plants)

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microfibrils (more abundant than microfibrils)a. agar/agaroseb. carageenan (after Irish Co b/c Chondrus crispus)

Function: elasticity/flexibility (cope with water motion), desiccation prevention, osmoregulation (ion exchange), dispersal/motility?, fusion with other cells, wound repair, parasitism, increases in length/volume, attachment

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Human Uses of Rhodophyta

• Food • nori (Porphyra)• 1949 life cycle completed – advanced cultivation techniques

• Phycocolliods = dervived from mucilagenous polysaccharides of cell walls

•Thickeners

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•Stabilizers•Gels

•Two important phycocolliods:• Carageenan (toothpaste, cosmetics, chocolate milk, ice cream, dessert gels, pet foods), found in Chondrus, Gigartina, Eucheumaand Kappaphycus•Agar (food gel, pharmaceutical capsules, medium for culturing microorganisms, gel electrophoresis), found in Gelidium, Gracelaria, Pterocladia, and Ahnfeltia

Rhodophyta Cell Characteristics: large cells due to:

1. Multinucleate = one cell has multiple nuclei# of nuclei correlated to the number of plastids

(replication, mitosis, no cytokinesis)

2. Polyploidy- repeated genome duplication

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yp y p g pbuffer against mutation of essential genes

(Endoreduplication = replication, no mitotic nuclear division)

Apical cell:

Cell characteristicsUninucleatenon- polyploid

Multinucleatenon-polyploid

Uninucleatepolyploid

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Derived cells:

Multinucleatenon- polyploid

Uninucleatenon- polyploid

Uninucleatepolyploid

Multinucleatenon- polyploid

Multinucleatenon- polyploid

Uninucleate, polyploid

Cell characteristics

Apical cell:

Uninucleatenon- polyploid

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Derived cells:

Examples:

Multinucleatenon- polyploid

Polysiphonia

Multinucleate,non- polyploid

MicrocladiaMazzaella, Callithamnion, Chondracanthus

Uninucleatepolyploid

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Pit plugs- structural support between cells

Old name: “pit connections”

• Protinaceous plugs between cells

• Primary pit plugs f d d i ki i b

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formed during cytokinesis between2 daughter cells within a filament

• Not a real connection – unlike browns, not for transport

• Secondary pit plugs formed between non-related

Pit plugs- structural support between cells

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formed between non related cells within and individual among filaments or between individuals (parasites)

-Unicellular- solitary non motile cells

- Filamentous- chain of cells

-Parenchymatous- undifferentiated

Rhodophyta Morphology

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-Parenchymatous- undifferentiated, isodiometric cells generated by a meristem

- Pseudoparenchymatous- form of thallus composed of interwoven continuous filaments

Polysiphonous – composed of tiers of vertically elongated cells, transversely arranged, the lateral cells around a central axis (siphon)

central filament surrounded by 4 or more pericentral cells

MAC Key: Cells in a regular transverse series

24Polysiphonia

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Cortication : elaboration of polysiphonous condition where pericentral cells continue to proliferate

25Partial Cortication

Reds often display growth through cell elongation

Growth

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New growth = not florescent

Cell repair by cell fusion

– filamentous growth in 2 directions, results in thallus composed of both prostrate + erect components

Heterotrichous Growth

= cell divisionIntercallary meristem

Epithallus

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Epithallus

Parithallus

hypothallus

Apical meristem

Uniaxial Growth- one longitudinal central filament forming the axis

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Multiaxial Growth- several longitudinal medullary filaments, each derived from an apical cell

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• Spores – no flagella

• Gametes – no flagella

“S i ” fl ll d l f

Flagella? NO - lack of flagella has led to…

TRIPHASIC LIFE HISTORY

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• “Spermatia” = unflagellated male gametes; no free movement

• Passive dispersal by water

Has led to adaptations that allow survival during seasonal variation in habitat and herbivory pressure…(Some herbivores prefer eating one life history stage over another)

Division: Rhodophyta- 7,117 species

Ei ht l ss s

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Eight classes Focus on 3 classes:

1. Class: Porphyridiophyceae -12 species2.Class: Bangiophyceae-197 species3.Class: Florideophyceae- 6,767 species

Division: Rhodophyta- 6504 species1. Class: Porphyridiophyceae -12 speciesOrder: Porphyridales

• Unicellular

• “a little round thing”

• Soil, Arial habitats, Fresh water, Brackish, Marine

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•Surrounded by a mucilaginous sheath

• Large stellate chloroplast

• Reproduction by cell division, release of vegetative cells or by endosporesGenus: Porphyridium, Rufusia

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Division: Rhodophyta- 6504 speciesClass: Porphyridiophyceae -12 species

Order: PorphyridalesGenus: Porphyridium

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Division: Rhodophyta- 6504 species1.Class: Porphyridiophyceae -12 species

Order: PorphyridalesGenus: Rufusia

Found only in sloth hair

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- “simple” reds

- unicells, filaments, parenchymatous blades

- marine, terrestrial, freshwater

uninucl t

Division: Rhodophyta- 6504 species2.Class: Bangiophyceae-158 species

Order: Bangiales

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- uninucleate

-one stellate chloroplast per cell

- pit plugs rare; if present, only primary, and in 2N stage

- biphasic life history

Genus: Bangia & Pyropia

Genus: Bangia

• Unbranched uniseriate filament in early development; later becomes multiseriate; rhiziodial extensions of lower cells

•2N conchocelis stage like Pyropia

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g y p

•Asexual reproduction by monospores

• Pit plugs present in conchocelis stage but not in gametophyte

•Inhabits upper intertidal splash zone on rocks – rarely epiphytic

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Genus: Pyropia (Porphyra)1N gametophyte: parenchymatous blade monostromatic or distromatic

2N sporophyte: “conchocelis” stage discovered in 1949 by Kathleen

B k E

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Drew Baker REVOLUTION microscopic filament lives on/in mollusk shells perennial

• Haplodiplontic life history• Saxicolous or epiphytic/endophytic• Harvested for nori

Algal Life Histories :TerminologySpermatium, spermatia (pl) = a non motile cell that

functions as a male gamete

Carpogonium = female gamete

Conchocelis stage= 2N filamentous stage; lives in/on CaCo3 shells of mollusks

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Conchospore = 1 N spore produced by 2N conchocelis stage

Monospore= 1N or 2N asexual spore that develops into the same phase as the parent

Asexual vs. Sexual: gametophyte switches from monospores to gametes; triggered by daylength (fall = shorter days = sex)

2N

syngamy

carpogonium

spermatium

Life History of Bangaliales ex PyropiaHaplodiplontic Alternation of Generations: organism having a separate multicellular diploid sporophyte and haploid gametophyte stage

MtMt

39monospore

2N carposporesp g

meiosis occurs inconchosporangium

microfilamentous2N conchocelis stage

1N conchospore

monospore

plantlet1N

gametophyticmacrothalli

MtMt

Me

Division: Rhodophyta-2.Class: Bangiophyceae-

Order: Bangiales

Spermatia from male gametophyte

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fertilizationcarpogonium

gametophyte

Capogonium divides to form carpospores-No gominoblast

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- advanced reds

- always multicellular: filaments or psuedoparenchymatous

-marine, freshwater

-almost always multinucleate

Division: Rhodophyta- 6504 species3.Class: Florideophyceae-6199 species

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-many discoid chloroplasts

-primary and secondary pit plugs

- triphasic life history

Triphasic Life History

1) Gametophyte: haploid, 1N multicellular releases gametes

2) Carposporophyte: all 2N material on the female gametophytewhere the 2N zygote is cloned to form the carposporesreleases carpospores

3) Tetrasporophyte: diploid, 2N multicellular releases tetraspores

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1N gametophytes

mitosis

2N carposporophyteon 1N female gametophyte

2N

1N

1N

Carpogonium on a carpogonial branch

Multiple 2N carposporesproduced through mitosis ingominoblast filaments

2N carpospores

432N tetrasporophyte

growth

2N

1N

meiosis

1N tetraspores

Triphasic Life Histories :Terminology trichogyne

cb

cp

cb

cpFemale Gametophyte-hapliod, 1n, multicellular produces gametes

Carpogonial branch (cb)= filamentous branch on which the carpogonium are formed

Carpogonium (cp) =female gamete

Trichogyne = extension of egg to which spermatium attaches

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Male Gametophyte-hapliod, 1n, multicellular release gametes

Spermatangial branch = filamentous branch which holds the spermatangia

Spermatangium, Spermatangia-male reproductive structure that produce spermatia

Spermatia= male gamete

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Male gametophyte - Polysiphonia

Triphasic Life Histories :Terminology

tricoblasts

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Female gametophyte - Polysiphonia

Trichoblast = usually a uniseriate filament of cells (with little pigmentation) that either remains sterile or can undergo division to form either spermatangia or carpogonium.

spermatangia

1N gametophytes

mitosis

2N carposporophyteon 1N female gametophyte

1N

2N

1NCarpogonium on a carpogonial branch

Multiple 2N carposporesproduced through mitosis ingominoblast filaments

2N carpospores

tricogyne

spermatia

462N tetrasporophyte

growth

2N

1N

meiosis

1N tetraspores

Carposporophyte = diploid, multicellular, one of the 2N generations; develops from the fusion of the carpogonium & spermatium (all 2N material on the female gametophyte); this is where the 2N zygote is cloned to form the carpospores

Pericarp = 1N vegetative tissue that surrounds the carposporophyte

Cystocarp = pericarp (1N) + carposporophyte (2N).

Carposprorangia = reproductive structures that produce carpospores

Gonimoblast = 2N filaments bearing carposporangia in the carposporophyte

Carpospore = dipliod (2n) spore formed by mitosis by the carposprophyte

Triphasic Life Histories :Terminology

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Carpospore = dipliod (2n) spore formed by mitosis by the carposprophyte

2N

1N

1N gametophytes

mitosis

2N carposporophyteon 1N female gametophyte

2N

1N

1N

Carpogonium on a carpogonial branch

Multiple 2N carposporesproduced through mitosis ingominoblast filaments

2N carpospores

482N tetrasporophyte

growth

2N

1N

meiosis

1N tetraspores

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( )

( )

( )

( )

( )( )

MtMt

Gametophyte (1N)

Carpospoophyte (2N)

Carpospores (2N)

Me

Gametophyte (1N)

Tetrasporophyte (2n)

Tetraspores (1N)

Tetrasporophyte = diploid, multicellular, one of the 2n generations; develops from germinating carpospore & release tetraspores

Tetrasporangium = 2N cell which undergoes meiosis to form 4 tetraspores

Tetraspore = haploid (N) spore formed by meiosis by the tetrasporophyte

Triphasic Life Histories :Terminology

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types of tetraspore arrangement within the tetrasporangia(four 1N spores)

ZonateCruciate(two views)Tetrahedral

Mazzaella

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1N gametophytes 2N carposporophyteson female gametophyte

2N tetrasporophyte

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1N gametophytes

2N carposporophyteson female gametophyte

Mastocarpus species complex

532N tetrasporophyte