CyanobacteriaCyanobacteriaandand

AlgaeAlgae

Prokaryotes and Prokaryotes and EukaryotesEukaryotes

Prokaryotes Eukaryotes

“primitive nucleus” “true nucleus”

Lack clear nucleus and other inclusions

Clear nucleus and other inclusions

All organisms with cells that lack a nucleus

All organisms with cells that have a nucleus

Nutritional Requirements Nutritional Requirements of Prokaryotesof Prokaryotes

Methods of obtaining carbonMethods of obtaining carbon Autotroph (“self-feeding) Autotroph (“self-feeding) incorporate incorporate

carbon into organic molecules from inorganic carbon into organic molecules from inorganic sourcessources

Heterotroph (“other feeding”) Heterotroph (“other feeding”) derive derive carbon from breakdown of organic carbon from breakdown of organic compoundscompounds

Methods of deriving energyMethods of deriving energy Chemotroph (“chemical feeding”) Chemotroph (“chemical feeding”) obtain obtain

energy from catalyzing inorganic reactionsenergy from catalyzing inorganic reactions Phototroph (“light feeding”) Phototroph (“light feeding”) obtain energy obtain energy

by absorbing light photonsby absorbing light photons

Symbiotic Relationships Symbiotic Relationships Between Prokaryotes & Between Prokaryotes &

PlantsPlants RhizobiumRhizobium lives in soil lives in soil

Synthesizes enzyme nitrogenase which Synthesizes enzyme nitrogenase which converts unusable Nconverts unusable N22 to plant-available to plant-available ammonium (NHammonium (NH44

++))

Forms mutualistic relationship with Forms mutualistic relationship with legumes within root noduleslegumes within root nodules Plant → carbohydrates & protectionPlant → carbohydrates & protection Bacterium → nitrogenase & other enzymesBacterium → nitrogenase & other enzymes Both benefit from supply of fixed nitrogenBoth benefit from supply of fixed nitrogen

CyanobacteriaCyanobacteria“blue green algae”“blue green algae”

PhotosyntheticPhotosynthetic chlorophyll chlorophyll a, a, phycobilinsphycobilins fix nitrogenfix nitrogen

Symbiotic Relationships Symbiotic Relationships Between Prokaryotes & Between Prokaryotes &

PlantsPlants Other examples of symbiotic Other examples of symbiotic

nitrogen fixing Bacterianitrogen fixing Bacteria FrankiaFrankia – within cells of root nodules of – within cells of root nodules of

aldersalders AnabaenaAnabaena – association with water fern, – association with water fern,

AzollaAzolla NostocNostoc – invades cavities in – invades cavities in

gametophytes of hornworts & cycadsgametophytes of hornworts & cycads

Figure 17.11

Photosynthetic Photosynthetic ProtistsProtists“Algae”“Algae”

Algae = Photosynthetic Algae = Photosynthetic ProtistsProtists

Variety of life histories, body forms, Variety of life histories, body forms, ecological rolesecological roles

Often named for distinctive colorsOften named for distinctive colors Unicellular, colonial, multicellularUnicellular, colonial, multicellular

Phylum ChlorophytaPhylum Chlorophyta“green algae”“green algae”

Unicellular, colonial, multicellularUnicellular, colonial, multicellular Most found in freshwater, also some Most found in freshwater, also some

in shallow marine habitatsin shallow marine habitats Pigments: chlorophyll a & b, Pigments: chlorophyll a & b,

carotenoidcarotenoid Food stored as starchFood stored as starch Cellulose cell wallsCellulose cell walls

Green AlgaeGreen Algae

(a)

(b)

(c)

50 µm

Algal ReproductionAlgal Reproduction Zygotic Zygotic

diploid phase of life cycle is single-celled zygotediploid phase of life cycle is single-celled zygote Examples: Examples: VolvoxVolvox, green algae, , green algae, ChlamydomonasChlamydomonas

GameticGametic Multicellular sporophytesMulticellular sporophytes haploid phase of life cycle is single-celled gametehaploid phase of life cycle is single-celled gamete Examples: some brown algae like Examples: some brown algae like CystoseiraCystoseira

SporicSporic multicellular gametophytes & sporophytesmulticellular gametophytes & sporophytes Examples: Examples: Ectocarpus, UlvaEctocarpus, Ulva (isomorphic), (isomorphic),

LaminariaLaminaria (heteromorphic) (heteromorphic)

Zygotic l.h found commonly in green algae

Gametic l.h. found in someBrown algae, especially rockweeds(Fucus, Pelvetia, Cystoseira)

Sporic l.h. found in kelps, green algae, land plants

Zygotic Life Cycles Zygotic Life Cycles ChlamydomonasChlamydomonas

Figure 18.

UlothrixUlothrix Life Cycle Life Cycle

Figure 18.

SpirogyraSpirogyra Sexual Sexual ReproductionReproduction

Phylum Chromophyta Phylum Chromophyta (Stramenopiles) (Stramenopiles)

All have 2 unequally sized flagella All have 2 unequally sized flagella (hairy & smooth)(hairy & smooth)

Photosynthetic ones include: Photosynthetic ones include: Chrysophyceae (golden algae)Chrysophyceae (golden algae) Bacillariophyceae (diatoms)Bacillariophyceae (diatoms) Phaeophyceae (brown algae)Phaeophyceae (brown algae)

ChrysophyceaeChrysophyceae“golden algae”“golden algae”

Carotenoid Carotenoid pigmentspigments

Usually Usually biflagellated biflagellated

Most unicellular, Most unicellular, some colonialsome colonial

Cell wall of Cell wall of cellulosecellulose

Figure 28.17

25 µm

BacillariophyceaeBacillariophyceae “diatoms”“diatoms”

Unicellular algae with Unicellular algae with silica tests (cell wall) silica tests (cell wall)

Important Important phytoplanktonphytoplankton

Contain chl. a & c, Contain chl. a & c, fucoxanthinfucoxanthin

3 µ

m

Reproduction in DiatomsReproduction in Diatoms

PhaeophyceaePhaeophyceae“brown algae”“brown algae”

abundant in cool, shallow abundant in cool, shallow marine watersmarine waters

Largest algae, multicellular Largest algae, multicellular thallusthallus

Life history sporic or gameticLife history sporic or gametic More More Chlorophylls Chlorophylls aa & & cc, ,

fucoxanthinfucoxanthin Carbohydrates can move Carbohydrates can move

through sieve elements & be through sieve elements & be stored (“mannitol”)stored (“mannitol”)

Cell wall of cellulose & alginCell wall of cellulose & algin

Blade

Stipe

Holdfast

Figure 18.

GametGameticic

(film)(film)

SporicSporicLife CycleLife Cycle

Phylum Phylum RhodophytaRhodophyta“red algae”“red algae”

WidespreadWidespread Shallow to deep waterShallow to deep water Warm to cool waterWarm to cool water

Chlorophyl a, phycobilinsChlorophyl a, phycobilins complex life cycle involving three complex life cycle involving three

types of thallus structures (“triphasic types of thallus structures (“triphasic life cycle”)life cycle”)

Cell wall of cellulose, agar or Cell wall of cellulose, agar or carrageenancarrageenan

.

(b)

(c)

Figure 18.

TriphasicTriphasicLife CycleLife Cycle

Phylum EuglenophytaPhylum Euglenophyta“euglena”“euglena”

““mixotroph”, contains chlorophyll a mixotroph”, contains chlorophyll a & b& b

No cell wallNo cell wall Contains eyespotContains eyespot Lack cell wallLack cell wall

Phylum DinophytaPhylum Dinophyta“dinoflagellates”“dinoflagellates”

UnicellularUnicellular Contain two flagella.Contain two flagella.

1 trails from the cell1 trails from the cell 1 encircles the cell1 encircles the cell

disc-shaped chloroplasts disc-shaped chloroplasts with xanthophyll pigmentswith xanthophyll pigments

Many with tiny projectilesMany with tiny projectiles Many produce toxins (Red Many produce toxins (Red

Tides)Tides)

DinoflagellatesDinoflagellates

Ecological & Economic Ecological & Economic ImportanceImportance

PhytoplanktonPhytoplankton Base of aquatic food chainsBase of aquatic food chains Produce about 4x food as earth’s cropsProduce about 4x food as earth’s crops

Help build tropical reefsHelp build tropical reefs Coralline green & red algaeCoralline green & red algae

Medicine, food, and fertilizerMedicine, food, and fertilizer Uses of algal cell walls Uses of algal cell walls

diatomitediatomite for filtering, bulking, abrasive for filtering, bulking, abrasive agaragar as culture medium, gel electrophoresis & as culture medium, gel electrophoresis &

in bakingin baking carrageenancarrageenan used as stabilizer used as stabilizer alginalgin used to absorb water & as additive used to absorb water & as additive

Kelp movieKelp movie