Final Flashcards
Sporangium vs Gametangium
Sporangium: Spore producing cell, diploid
Gametangium: Carries the gamete, haploid
Diplohaplontic lifecycle
- alternation of generations with 2N sporophyte and N gametophyte
- switches between haploid and diploid
Isomorphic generations
Similar N and 2N stages where sporophyte and gametophyte are similar in structure and general appearance
Heteromorphic generations
Dissimilar N and 2N stages where sporophyte is more complex structurally (parenchymatous or pseudoparenchymatous) and gametophyte is filaments
Heterotrichous
Different filaments
Plurilocular sporangia vs Unilocular sporangia vs Plurilocular gametangia (Brown Algae - Ectocarpus)
Plurilocular sporangia: have multiseriate region consisting of large number of smaller cells, each cell develops into asexual zoospore (2N) that produces new sporophyte, dominate at warmer temperatures
Unilocular sporangia: are enlarged cells where meiosis occurs followed by several mitosis divisions, releases 32 to 64 N spores, each giving rise to a gametophyte, dominate at cooler temperatures
Plurilocular gametangia: resemble plurilocular sporangia, gametes (N) are isogamous with laterally inserted flagella, males and females similar in appearance but functionally distinct, as females settle to bottom and secrete chemical called ectocarpene which attracts males, after gamete fusion, the zygote develops without a period of dormancy into new sporophyte (2N)
Plurilocular sporangia (Brown Algae - Ectocarpus)
Plurilocular sporangia: have multiseriate region consisting of large number of smaller cells, each cell develops into asexual zoospore (2N) that produces new sporophyte, dominate at warmer temperatures
Unilocular sporangia (Brown Algae - Ectocarpus)
Unilocular sporangia: are enlarged cells where meiosis occurs followed by several mitosis divisions, releases 32 to 64 N spores, each giving rise to a gametophyte, dominate at cooler temperatures
Plurilocular gametangia (Brown Algae - Ectocarpus)
Plurilocular gametangia: resemble plurilocular sporangia, gametes (N) are isogamous with laterally inserted flagella, males and females similar in appearance but functionally distinct, as females settle to bottom and secrete chemical called ectocarpene which attracts males, after gamete fusion, the zygote develops without a period of dormancy into new sporophyte (2N)
Ectocarpine
Pheromone secreted by brown algae (Ectocarpus) that attracts pluriocular gametangia males.
Pheromones
Chemicals involved to ensure sexual reproduction, usually attracts the male gametes to the female.
When would brown algae (Order Ectocarpales) produce pluriocular sporangia?
In good water temps (asexual)
When would brown algae (Order Ectocarpales) produce uniocular sporangia?
Initiated by water temperature cooling (sexual repro - for surviving environmental adversity)
Heteromorphic alternation of generations
Sporophyte is usually very large, the haploid gametophyte is usually microscopic
Dioecious gametophytes (Brown algae - Laminariales)
- bear oogonia (female) and antheridia (male)
- Oogonium produces one egg that remains attached and antheridium produces one sperm
- Egg secretes pheromone (lamoxirene) that stimulates antheridia to release sperm that swim to egg
Sexual reproduction in brown algae - Laminariales:
- Process, and parts used.
- What’s produced.
- Type of repro (iso, etc)
- Dioecious or monoecious.
- Pheromone?
Sexuality is oogamous
Sporophyte produces unilocular sporangia and paraphyses on frond suface (some kelps have specialized sporophylls)
Produces N zoospores which produce microscope N gametophytes
Dioecious gametophytes bear oogonia (female) and antheridia (male)
Oogonium produces one egg that remains attached and antheridium produces one sperm
Eggs secretes pheromone (lamoxirene) that stimulates antheridia to release sperm that swim to egg
After fertilization, sporophyte overgrows gametophyte
Cryptostomates
- Small cavities scattered over surface, appearing as small bumps, that aid in nutrient uptake
- Order Fucales (brown algae)
Receptacles
- Brown algae (order Fucales)
- Specialized reproductive regions called receptacles at ends of branches
- Receptacles contain conceptacles
- Can be monoecious (one gamete) or dioecious (two gametes) conceptacles
- Branches inside conceptacles produce gametangia: oogonia (larger, female) and antheridia (smaller, male)
- Gametes released in packets through conceptacle opening into surrounding seawater during calm periods for maximum fertilization
Lamoxirene
Pheromone in brown algae, order laminariales - secreted by egg, stimulates antheridia to release sperm that swims to egg
Brown algae orders with diplontic life cycle
order fucales
fucoserratene
pheromone produced by brown algae, order fucales
Sexual reproduction in brown algae - Fucales:
In antheridia, meiosis followed by repeated mitosis forms packets of 64 sperm
In oogonia, meiosis and single mitosis forms packet of 8 eggs
Gametes released in packets though conceptacle opening into surrounding seawater
Gamete release restricted to calm periods for
maximum fertilization success
Pheromone (fucoserratene) attracts sperm to eggs
Zygotes secrete adhesive to aid in surface attachment
Is brown algae benthic or planktonic?
Larger species are benthic (rocky shores); only a few planktonic
What temp do brown algae prefer, and how big can they grow?
- Phaeophyceae diversity greatest in colder (<20 °C) oceans of northern and southern hemispheres
- Giants kelps may grow to 45-60 m in length (0.6 m/day) with blades 1.2 in length and 0.3 m in width: “Sequoia of the Seas” in vast underwater forests
Intertidal habitat
brown algae provide intertidal habitat by maintaining well-illuminated, moist environment under fronds for epiphytes and sessile invertebrates
What is the use for kelp (brown algae)?
- Kelp eaten as vegetable, providing salts, vitamins, trace elements
- Kelp harvested for ash (Na, K) for industry and used as fertilizer
Use for iodine.
Iodine reacts with starch (a storage product) and makes it turn black.
Alginate
Alginates from Phaeophyceae cell wall
Absorbs many times its weight in water
Thickening agent, colloid stabilizer, and gelling agent in wide variety of foods (e.g., algin in fruit pie fillings stop fruit pulp from leaking into pastry), beverages (e.g., foam stabilizer in beer), textiles (dye thickener) and cosmetics
Algin in pharmaceuticals regulate rate at which they are released into bloodstream
Moisture retainer in loose, sandy soil
Slow release of trace elements (organic fertilizer)
How are Tribophyceae (Xanthophyceae/ yellow algae) similar to chromophytes? 5 reasons.
- Thylakoids in stacks of three (lamellae)
- Reserve storage product is chrysolaminarin, commonly as
oil or fat droplets - Chlorophyll A as primary photosynthetic pigment, sometimes with accessory xanthophyll (just 3 classes) but no fucoxanthin so cells appear yellow-green or green 4. Chloroplasts surrounded by four membranes
- Cell wall has cellulose microfibrils with a small amount of silica, may consist of 2 overlapping halves like diatoms.
Difference between Tribophyceae (Xanthophyceae/ yellow algae) and green algae (Chlorophyta)?
Distinguished by pigments and storage product: green algae have chlorophyll B and true starch
- Tribophyceae have chloro A, may have xanthophyll (no fucoxanthin)
- Chrysoplaminarin as storage product
Colonial
Aggregation of cells, are nonmotile and are embedded in common sheath of mucilage
Pyrenoids
where carbon fixation takes place in the chloroplast
Parietal
Around the cell (the periphery)
Endogenous vs Exogenous
Endogenous: cyst formed inside the cell
Exogenous: cyst formed outside the cell
Cell wall composition and morphology of tribophyceae
- Composed of cellulose microfibrils with small amount of silica
- Sometimes consist of two overlapping halves (e.g.,
Tribonema) but sometimes not visible without chemical (somewhat similar to diatoms)
Chromatophore
pigment containing plastid (chloroplast)
Chloroplasts + thylakoids + pyrenoids (present or not) of tribophyceae
- Four membranes in chloroplasts
- Parietal within cell, discoid in shape, yellow-green in colour
- Vary in number from two to many
- Thylakoids groups in threes (lamellae)
- Pyrenoid present in many genera
Pigments and storage product of tribophyceae
- Chlorophyll A with small amounts of C1 and C2
- Accessory pigments are β-carotene and xanthophylls
(NO fucoxanthin)
- Principal storage product is chrysolaminarin
Flagellae of tribophyceae (morphology, number, photoreceptor present? eyespot?)
When present (motile taxa, zoospores, gametes), they are typical heterokontous chromophyte type
Long anterior tinsel flagellum with tripartite hairs (mastigonemes) and shorter posteriorly-directed whiplash flagellum inserted in anterior region of cell
Have photoreceptor (flagellar swelling on shorter, smooth flagellum) and eyespot (in chloroplast)
Which reproductive stages are flagellated?
Zoospores and gametes
Algal groups with only asexual reproduction
tribophytes, cyanophyta
Reproduction in tribophyceae (asexual or sexual, and how)
In most tribophytes, only known method is asexual: Vegetative cell division (fragmentation)
Formation of zoospores (motile), aplanospores (nonmotile), or cysts
Zoospores and aplanospores are produced by division of cellular cytoplasm into 1, 2 or several subunits and release from cell
Cysts formed inside cell (endogenous)
Asexual reproduction (what’s formed, motile or not)
- Vegetative cell division (fragmentation)
- Formation of zoospores (motile), aplanspores (nonmotile), or cysts
lifecycle type in tribophyceae?
haplontic
Cryptomonad
• Monad: small uniflagellates
• Crypto: hidden; reflect uncertain phylogeny
Cryptomonad: don’t understand fully on how they evolved
Sessile
non-motile
Lamellae
Three stacked thylakoids in chloroplast
What happens when iodine reacts with starch?
turns black
Vestibule
Insertion point on cell surface where flagella originates in (a groove)
- present in crypto monads
Algal group with plasma membrane modified as periplast
Cryptomonads
Periplast (+ what group has it)
- Cryptomonads
- Periplast goes around as a modified plasma membrane
- Proteinaceous plates associated with inner side of the cell membrane, separated by ejectosomes
Cell membrane + ejectosomes = periplast
Bilobed chloroplast (+ who has it)
- Cryptomonads
- One lobe of connected to another lobe to form the chloroplast
palmelloid arrangement
- many algae enclosed in mucilage
- cryptomonads
Ejectosomes
-Little membrane bound structure from periplast that is ejected
-Are projectiles usually
of two types: large (20 μm when discharged) or small (4 μm when discharged)
-Long tapered ribbon, tightly spiralled and enclosed in single membrane
-Discharged explosively when cell is disturbed, like a party favour
-Thought to serve as defence or escape mechanism
Nucleomorph (+who has it)
- intermediary between the chloroplast and nucleus, looks like a nucleus (what it may have been before), like vestigial nucleus but still some use for it
- provides proof of secondary endosymbiosis, has remains of nucleus of the original cell that was engulfed
- has chromosomes (3 pairs which code for the proteins of the chloroplast, NOT in nucleus but the information to make chloroplasts is found in the nucleomorph)
- Cryptomonads
algal group with nucleomorph
cryptomonads
Pigment location in cryptomonads
- intrathylakoid **
- pigments between thylakoids (not thylakoid surfaces as usual)
Auxotrophic
Mostly photolithotrophic but requires a nutrient that it can’t make itself
- must be provided with organic matter
- ex. require vitamin B12
Mixotrophic
Capable of either heterotrophy or autotrophy based on whichever is most favourable.
Chloroplast morphology and number of membranes in cryptomonads
- Single, bi-lobed chloroplast with central pyrenoid
- Four membranes (result of secondary endosymbiosis of photosynthetic, red algal cell – nucleomorph between inner and outer membranes of chloroplast is remnant of its nucleus)
thylakoid numbers and pigments (type and location) in cryptomonads
- Thylakoids in pairs, sometimes in threes
- Chlorophylls A and C
- Phycobilins in intra-thylakoid spaces not on surface
Storage product in cryptomonads
true starch
Heterotrophy (both autotrophy and mixotrophy) in cryptomonads
- Some taxa are auxotrophic, requiring such organics as
vitamin B12 to achieve maximum growth rate
- Many taxa are mixotrophic, capable of phagotrophy of bacteria and other small cells
Asexual reproduction in cryptomonads
- Mostly asexual via mitosis and cytokinesis
- Some species produce cysts or palmelloid stages to
withstand adverse conditions or deter grazers
- Sexual reproduction is rare
Sexual reproduction in cryptomonads
- Sexual reproduction is rare:
Isogamous with vegetative cells acting as gametes
- Gametes fuse to form quadriflagellate zygote which divides by meiosis to form haploid vegetative cells
- Haplontic lifecycle
Kleptoplastidity (+which group)
- “to steal plastids”
- cryptomonad chloroplasts ingested by ciliates and dinoflagellates remain functional, producing starch, for several days
- Cryptomonads
Would you find cryptomonads in high or low nutrient waters?
cryptomonads sometimes common where organic matter content is high (probably due to facultative phagotrophy)
Phytoplankton
Free-floating
How do some algae withstand adverse conditions or deter grazers?
Produce cysts and palmelloid stages
Dinoflagellates
Dino = whirling flagellates or corkscrew due to their means of motility
Heterodynamic + example
Two flagellae that don’t move one the same direction (ex. dinoflagellates)
1st and 2nd most important algal groups in terms of primary productivity
- Diatoms first
- Dinophyta second
Theca
- Modified cell membrane
- “Covering” or “coat”
- In Dinoflagellates, have thecal plates under the membrane, NOT armour - the cell membrane is over top!
- Function of the theca may help with floatation and surface area
- Fewer the number of plates, the thicker and more robust they are (varies with species)
- Plates are joined by sutures
Cell wall/membrane of dinoflagellates
-Modified plasma membrane with fibrous cellulosic plates beneath plasma membrane, the theca
-“Covering” or “coat”
-In Dinoflagellates, have thecal plates under the membrane, NOT armour - the cell membrane is over top!
-Function of the theca may help with floatation and surface area
-Fewer the number of plates, the thicker and more robust they are (varies with species)
-Plates are joined by sutures
- Number of thecal plates varies with species (thicker the
plates, fewer per cell)
- Some taxa have vesicles devoid or almost devoid of contents (appear naked or non-thecate)
- Microtubules located below vesicles, randomly distributed or in discrete groups
Sutures
join plates of dinoflagellate theca
Mesokaryotic nucleus + who has it
- “Middle nucleus”
- Intermediate stage between prokaryotes and eukaryotes
- Doesn’t expand its chromosomes during interphase, remain condensed (+visible) through the entire cell cycle and are rod-shaped
- No histone proteins in chromosomes
- Can have constant DNA replication
- Nuclear membrane persists
Nucleus of dinoflagellates
- mesokaryotic
- “Middle nucleus”
- Intermediate stage between prokaryotes and eukaryotes
- Doesn’t expand its chromosomes during interphase, remain condensed (+visible) through the entire cell cycle and are rod-shaped
- No histone proteins in chromosomes
- Can have constant DNA replication
- Nuclear membrane persists
Trichocyst + who has it
- In Dinoflagellates
- Membrane-bound crystalline rod (penetrates into cell)
- A projectile organelle to deter predators (similar to discobolocytes or ejectosomes) or to escape
- At the suture lines (junction point of plates)
Cingulum and Sulcus, how they contribute to motility, and who has it
Cingulum (wraps around the cell) and sulcus (runs down the cell in one direction) each have a flagellum
- Heterodynamic flagella
- In dinoflagellates
- Sulcus one (larger) propels organism forward
- Smaller one in cingulum causes a barrel role –> corkscrew motion through water
What is a clue of an algae’s evolution?
what pigments they contain
Haplontic lifecycle
most of the lifecycle is haploid except for the zygote stage which is diploid
Phagotrophic
Solid particles ingested into food vesicles where they are broken down and absorbed into cytoplasm
Heterotrophic
need organic material, can’t synthesize themselves
** exam
Pantonematic vs Acronematic
Pantonematic: tinsel or hairy flagellum
Acronematic: smooth or whiplash flagellum
Epicone vs Hypocone
the theca of dinoflagellates-
Epicone: Top part above + including the cingulum but not sulcus
Hypocone: Bottom part, with sulcus
Apical vs Singular plates
the theca of dinoflagellates-
Apical plates = at top of epicone
Singular plates = along the Cingulum
In dinoflagellates, which flagella is tinsel/ pantonematic and which is whiplash/ acronematic?
Pantonematic: tinsel or hairy flagellum - girdle/cingulum flagella
Acronematic: smooth or whiplash flagellum - sulcus flagella
____ join plates of dinoflagellate theca
sutures
function of horns in dinoflagellates
increases SA for buoyancy, not for protection at all
Describe the four types of eyespots.
- Simplest type: collection of lipid globules lying freely in cytoplasm (no membrane)
- Row of small globules within chloroplast
- Two rows of lipid globules surrounded by triple membrane in cell periphery
- Most complex eye or ocellus (lens and pigment cup); Lens acts as a focusing device
Eyespot of dinoflagellates
- Found in <5% of species
- Most complex among algae:
Most complex eye or ocellus (lens and pigment cup); Lens acts as a focusing device
Chloroplasts in dinoflagellates
- Only in ~ 50% of taxa; rest are heterotrophic and lack chloroplasts
- Discoid or lobed
- Peripheral location
- Variable number
- Unique chloroplasts (three membranes, different accessory pigments)
Thylakoids and pyrenoids in dinoflagellates
- Thylakoids stacked in three
- Pyrenoid can be embedded in chloroplast or protruded into cytoplasm (in about 50% of dinoflagellates)
storage product in dinoflagellates
Storage product: starch or lipid droplets (long term storage)
Photosynthetic pigments in photolithographic members of dinoflagellates
- Chlorophyll A and C
- B-carotene, fucoxanthin, peridinin (unique to dinophyta), dinoxanthin
Most appear golden-brown or red due , to accessory
pigments that mask chlorophylls
Do all dinoflagellates have chloroplasts?
- 50% heterotrophic :
- Phagotropic (Solid particles ingested into food vesicles where they are broken down and absorbed into cytoplasm.
Prey on other dinoflagellates, other algae, large ciliates, nematodes, larvae, and fish).
50% not:
- auxotrophic (require B12)
- mixotrophic
only 50% have chloroplasts
Asexual reproduction (2) in dinoflagellates
- Mostly asexual reproduction via mitosis
- Each daughter cell usually receives some parental plates
- Cyst formation by replacement of theca with thin, amorphous sporopollenin-like wall that thickens
- Function unknown but thought to be ** part of lifecycle *** and not a way to survive adversity
- Forms inside the theca, after which cytoplasm migrates
inside through pore in cyst wall then original plasma
membrane and theca are shed
Are dinophyta haploid, diploid, or diplohaploid?
haploid
Mechanism of cyst formation in dinophyta
- Cyst formation by replacement of theca with thin, amorphous sporopollenin-like wall that thickens
- Function unknown but thought to be ** part of lifecycle *** and not a way to survive adversity
- Forms inside the theca, after which cytoplasm migrates
inside through pore in cyst wall then original plasma
membrane and theca are shed
Function of dinophyta cysts
Function unknown but thought to be ** part of lifecycle *** and not a way to survive adversity
Peridinin
- only algal group that contains this unique xanthophyll pigment are the Dinoflagellates
- an accessory pigment
- gives them a colour other than green
- a modified phycoerithrin
Why are cysts sometimes produced?
-for adverse environmental conditions like low food quantities (live in sediment for a long time)
or
may also just be a normal part of the lifecycle for dinophyta (amoeboid stage and become saprophytic, eating organic matter in the sediments)
Sporopollenin
- in dinophyta
- thin and amorphous wall that thickens during cyst formation (replaces theca of dinoflagellates)
- material produced by spores
- extremely robust
- in pollen that has survived thousands of years
- are armored due to outer layer
Sporopollenin
- in dinophyta
- thin and amorphous wall that thickens during cyst formation (replaces theca of dinoflagellates)
- material produced by spores
- extremely robust
- makes up outside coat of pollen that has survived thousands of years
- are armored due to outer layer
Planozygote vs Hypnozygote
- In dinophyta
- Planozygote: flagellated zygote
- Hypnozygote: non-flagellated zygote (resting cyst), dormant stage
Anisogamous gametes
ex. dinoflagellates
female larger, male smaller
Sexual reproduction in dinoflagellates
- Two cells serve as isogametes or anisogametes
(look like vegetative cells except smaller and lighter colour)
- Larger (female) gamete absorbs the smaller (male) gamete to produce diploid zygote - -> Planozygote – flagellated zygote
- -> Hypnozygote – nonflagellated zygotes (resting cysts)
Zygote divides meiotically to produce four naked protoplasts, which eventually develop plates to become four dinoflagellates
Fast algae and how fast are they?
dinoflagellates
speeds up to 500 um/sec=1.8m/h
Do dinoflagellates migrate?
Daily vertical migrations, moving up by day for light, down by night for nutrients
- Diurnal rhythm
algae with diurnal rhythm
dinoflagellates (Daily vertical migrations, moving up by day for light, down by night for nutrients)
Saprophytic + which group
organisms that live off dead organisms, dead organic matter
- dinoflagellates
____ are parasitic on annelids, copepods and fish
dinoflagellates
Ichthyotoxin
-toxin produced by a dinoflagellate that targets fish
- dinoflagellate swarm attracted by chemicals released by fish prey
= dinoflagellates secrete ichthotoxin that promotes epidermal sloughing - fish had necropsy of their tissue (breaking down) and killed them, they eat the dead fish (saprophytic)
- if they kill all the fish and have no food, they can encyst, survive on other prey, or become a motile amoebae form and bloom again when food is replenished
Ichthyotoxin vs ichthiopathic
Ichthyotoxin = chemical toxic to fish, produced by a dinoflagellate
Ichthiopathic = fish killer
Endozoic
Living inside another organism (can be a symbiotic association), example is dinoflagellates that live in corals
How is a symbiosis formed between the corals and the dinoflagellates?
○ In corals, alga provides coral with oxygen, waste removal and carbohydrates, since about 60% of the carbon fixed by the alga is released into the surrounding medium and used by coral
○ Dinoflagellates help on the calcification of the matrix of corals (Calcium carbonate deposited due to algal photosynthesis assists in coral calcification; since this only occurs in light, restricts depth to which corals can occur)
○ That’s why they live in shallow water to receive light for the dinoflagellates that help them with the calcification
○Dinoflagellates get the nutrients from the surrounding host, and are also protected
Calcium carbonate
in dinoflagellate and coral symbiosis, the calcium carbonate (lime stone) deposited due to algal photosynthesis assists in coral calcification; since this only occurs in light, restricts depth to which corals can occur
Marl
photosynthetically produced limestone (ex. by dinoflagellates)
Red tides
“Red tides” mostly in tropical and subtropical waters
but also in temperate zones, usually close to coasts
○ Caused by Dinoflagellates
○ Blooms occasionally lead to death of aquatic animals when they consume oxygen during collapse or due to toxin production
○ Upside: it is thought oceanic dinoflagellate blooms produced much of the world’s petroleum deposits
○ Water turning to blood in the Bible due to these red tides, not an act of God
Why do some dinoflagellates produce a bioluminescent response?
○ Bioluminescent response where luciferin a chemical that produces light (flames from hell) and reacts with ATP = luciferase (an enzyme that mediates the reaction between ATP and luciferin)
○ Chemicals mix when propeller of the boat passes through or reaction to being startled (fish are attracted the the predator eating the dinoflagellate and eats them instead)
○Alarm to startle the burglar (burglar alarm hypothesis) and attract your neighbours or startle the grazers (startle hypothesis)
luciferin
a chemical that produces light (flames from hell) and reacts with ATP = luciferase (an enzyme that mediates the reaction between ATP and luciferin)
produced by dinoflagellates
burglar alarm hypothesis vs startle hypothesis
Dianoflagellates produce bioluminescence using luciferin.
Possible reason they do it:
Alarm to startle the burglar (burglar alarm hypothesis) and attract your neighbours or startle the grazers (startle hypothesis)
Saxitoxin
- Dinoflagellate endotoxin
- 50 times more potent than curare to birds and mammals but nontoxic to shellfish that are its primary consumer
- function unknown, but may be anti-predator mechanism (does not benefit the individual that has been eaten but may benefit the others that may survive)
Endotoxin
produced within cell and not released to environment until cell is crushed or destroyed
Neurotoxin
toxin that affects the nervous system
Flagella of euglenids
- 1 or occasionally 2 (sometimes more) heterokontous flagella arising from anterior invagination (gullet)
- Unique anatomy with usual 9+2 ultrastructure plus rigid paraflagellar rod
Paraflagellar rod:
- electron dense area
- rigid
- gives the flagella a unique movement (because its rigid)
- found in Euglenophyta
- more jerky movement, less flexible
- Euglnoid motion
Paraflagellar rod
- electron dense area
- rigid
- gives the flagella a unique movement
- found in Euglenophyta
- more jerky movement, less flexible
- Euglnoid motion
Euglenid eyespot and light response
- Prominent, red-coloured eyespot near basal flagellar swelling associated with longer of two flagella
- Euglenoid are positively phototactic at low light, negatively phototactic at high light (When high levels of light that could damage the photosystems)
Euglenoid motion
-twisting of the pellicle to propel the cell forward (streaming of cytoplasmic contents)
Pellicle
○ Proteinaceous strips beneath plasma membrane
○ Helically twisted with ridges and grooves
○ Some have flexible pellicle to allow for Euglenoid motion (others have a rigid pellicle)
○ Muciferous bodies with mucilage under pellicle strips
○ Discharge mucilage to exterior
- Some euglenids covered in dehydrated mucilage resembling a lorica, sometimes with Fe/Mn giving it red/brown colour
Nucleus type in dinoflagellates and euglenoids
mesokaryotic
Muciferous bodies in euglenoids
-excrete mucilage to lubricate the membrane or pellicle when it twists = Euglenoid motion
Photolithotrophic
use if light and inorganic material
Epipelon vs Epiphyton
Epipelon = sediment Epiphyton = plants
Bioassay (+ example)
- Use of living creature to tell you the concentration/ quantity of something.
- Egulena growth rate is used to determine the concentration of vitamin B12
Nutrition in euglenids
- None strictly photolithographic, probably all are auxotrophic.
- 1/3 can photosynthesize, probably mixotrophic
Chloroplast and number of chloroplast membranes in euglenids
- Many chloroplasts per cell but about 2/3 of euglenoids are achlorophyllous and obligate heterotrophs
- three chloroplast membranes (secondary endosymbiosis of a green alga)
Pigments (+ accessory ones) and presence or absence of pyrenoids in euglenids
- Pyrenoids may be present, located centrally
- Chlorophylls A and B (no C), like Green Algae
- Accessory pigments: β-carotene, neoxanthin, diadinoxanthin (most appear green, some red)
every alga has the pigment _____
chlorophyll a
Euglenid storage product
- paramylon (or paramylum)
- a storage product of Euglenophyta
- chemically similar to laminarin
- does not respond to iodine
paramylon
euglenoid storage product, does not respond to iodine
Endozoic (= example)
living inside animals like euglenids drangonfly nymphs
Reproduction in euglenids (not mechanism)
- Purely asexual or by encystment
- No confirmed reports of sexuality
- Encystment usually in response to adverse
environmental conditions (desiccation, high light, changing temperature)
1 algal group encysts as part of their lifecycle, NOT in response to adversity
dinoflagellates
Process of encystment in euglenids
- Cells slow down, become rounded, lost flagella, secrete heavy mucilaginous crust
- Cysts persist for months after which cell division occurs within mucilage before flagella reappear, forming palmelloid stage
- Germinating cysts responsible for green growth in puddles
- Cysts look red (high iron content) and the mucilage is extremely sticky.
- Located on neuston (surface of water interface where water meets air), which likely indicates mixotrophy - nutrient rich, shallow waters
neuston
surface of water interface where water meets air
Euglenids can live in these habitats, define them.
Epipelon
Epiphyton
Epizoon
sediment (epipelon)
plants (epiphyton)
zooplankton (epizoon)
Are red algae unicellular or multicellular?
Mostly multicellular: pseudoparenchymatous or filamentous; very few unicellular
- have specialized cells; reproductive, storage, photosynthetic, body, attachment, etc
2 algal groups that are never flagellated
red algae (rhodophyta) cyanophyta
Pigments in red algae (rhodophyta)
Chlorophylls A and D, carotenoids and phycobilins in phycobilosomes
phycobilosomes - pigments are exterior to thylakoids
From another slide:
Chlorophylls A and D with various carotenoids
Phycobilins in phycobilisomes on surface of thylakoids, similar to Cyanophyta:
Allophycocyanin
Phycocyanin
Phycoerythrin (predominant; gives red colour)
Freshwater species often blue-green due to predominance of phycocyanin
storage products in red algae (rhodophyta)
Storage product: Floridean starch (iodine
responsive)
Principal storage is Floridean starch (α-1,4- linked glucan, similar to true starch, more highly branched) as granules outside chloroplast, in cytoplasm (unlike green algae)
thylakoids (number and stacked or not stacked) in red algae (rhodophyta)
Thylakoids single, equidistant, and unstacked in chloroplasts, similar to cyanobacteria
unlike any other eukaryotic algae except Glaucophyta
flagella in red algae (rhodophyta)
NONE, ever. No motile stages at all.
Pseudoparenchymatous
3D tissue unable to identify a single filament
Pit plugs
- in red algae (rhodophyta)
- Proteinaceous pit plugs between adjacent cells in
many species (connections between cells) - like higher plants
-not a pit or connection - plug is deposited by endoplasmic reticulum
primary and secondary pit plugs function -
primary: allows for transport between cells until plugged
secondary:
- function in intercellular transport (when plugs are dislodged), can be parasitic
Primary pit connection vs Secondary pit connection in red algae
- Primary pit connection:
- when one cell divides it forms between the two cells (sister cells)
- gap left behind by incomplete division and ER condenses in gap forming plug - Secondary pit connection:
- Formed when two cells fuse (non-sister cells) because cell walls are soft
- May also be between 2 different organisms or even different species - parasitic, cell bonds to wall, dissolves the wall and connects itself so it can use the organism for transport, etc
- function in intercellular transport (when plugs are dislodged)
Cell wall of red algae (rhodophyta)
○ Fibrous portion of cellulose provides strength
○ Cellulose rather soft, not rigid, compared to other algae
○ Embedded in amorphous matrix of mucilage (agars and carrageenans) that is 70% of dry weight
Cell wall of red algae vs brown algae
○ Brown algae have rigid walls (two layers of cellulose, fibrillation network and an outer layer of alginate that allows the ability to resist drying out)
○Red algae live in same environments but adapted same strategy to survive dry environments, have cellulose, agar and carrageenan (chemicals formed by red algae that have similar roles as the alginate, also used in cosmetics, can hold lots of water); walls are must less rigid, so smaller due to less rigidity
Primary endosymbiosis vs Secondary endosymbiosis
in terms of number of chloroplast membranes
Primary = 2 membranes of chloroplast Secondary = 3 or 4 membranes of chloroplast
Average water consumption in Israel and Manitoba (same) in LCD (= laters per capita per day), for all uses and personal uses.
- All uses: 506 LCD
- Personal: 275-325
Proportion of water recycled in Israel
75% (MB recycles less than 1%)
describe the 2 options for meeting future water demand (hard path vs soft path)
“Hard path”
- Find new sources to meet increased demand
“Soft path”
- Conserve (use more efficiently) to avoid need for new sources
Why conserve water ?
Every liter of water conserved means ____ and ____.
- One liter of clean water available for
other purposes - One liter of gray water not requiring treatment
Anti-environmentalism
the gradual adoption of unconscious behavior founded in ignorance of, and disdain for, the natural environment, usually acquired with egoism, consumerism, and self-indulgence
United Nations: ___ LCD is minimum amount required to satisfy basic human needs
United Nations: 20 LCD is minimum amount required to satisfy basic human needs
chloroplasts of red algae (number of them, shape, number of membranes and what this means, presence of chloroplast ER (yes or no)?
Surrounded by two membranes of envelope with no chloroplast ER, probably resulting from primary endosymbiosis of cyanobacterium
What is the purpose of phycobilins in red algae?
- phycobilins allow for chromatic adaption of red algae
- they can grow at greater depths than other algae because blue and green light penetrate farthest into water
- chlorophyll A absorbs light at 400-500 and 600-700
- phycocyanin absorbs at 500-600 (or 550 or so)
- phycoerythrin absorbs at 450 to 600
together absorbs a huge spectrum which gives red algae an advantage in marine waters
Phycobilins
- allows for chromatic adaptation where photosynthetic organisms can modify them to adapt to the amount of light they are receiving
- take up a wider range of wavelengths of light from the spectrum
- allow for chromatic adaptation
Chromatic adaptation and phycobilins
- phycobilins allow for chromatic adaption of red algae
- they can grow at greater depths than other algae because blue and green light penetrate farthest into water
Which visible light goes through water the easiest?
- blue and green go through easiest (why the colour of water is blue)
- red and green not as easily
Nucleus of red algae
Uninucleate
Multinucleate (repeated mitosis without cytokinesis)
Polyploidy (replication of genome without mitosis, mechanism against mutation of essential genes)
Nucleus, and ploidy of red algae
Uninucleate or Multinucleate (repeated mitosis without cytokinesis)
Polyploidy (replication of genome without mitosis, mechanism against mutation of essential genes)
How do you get a multinucleate organism?
repeated mitosis without cytokinesis
Adelphoparasites vs Alloparasites
Adelphoparasites: closely related to hosts (90%)
Alloparasites: not closely related to hosts
How do parasites (red algae) connect to hosts?
- via secondary pit connections, transferring its nucleus to host, causing host cell to enlarge and increase in cytoplasmic content
- products of photosynthesis are transferred from host to parasite
Oogamous
two very different gametes
Monoecious
both male and female structures are on the same gametophyte
Why triphasic reproduction? Who has this?
- triphasic lifecycle (three phases) with isomorphic or heteromorphoic haplodiplontic alternation of generations
- because male gametes are nonmotile, it is compensation for lack of motility
- enhance reproductive fecundity
- In red algae
Describe asexual reproduction in red algae
Asexual reproduction involves formation of nonflagellated monospores (via mitosis in monosporangia) on gametophyte and tetrasporophyte
Describe sexual reproduction in red algae
- triphasic lifecycle (three phases) with isomorphic or heteromorphoic haplodiplontic alternation of generations
- because male gametes are nonmotile, it is compensation for lack of motility
- Oogamous (male and female non-flagellated)
Colony
loose aggregations of cells held together by mucilage or intercellular connections
Coenobium
a type of colony where the number of cells is fixed
Parietal chloroplast
around the cell
Karyokinesis vs cytokinesis
- karyokinesis = division of nucleus
- cytokinesis = division of cytoplasm
How is chlorophyll an indicator?
High chlorophyl levels can indicate high algae levels
Describe the gametophyte (N) stage in the triphasic lifecycle of red algae.
- Gametophyte (N)
Free-living; monoecious or dioecious
Male gametophyte produces spermatia (male gametes) from spermatangia via mitosis
Spermatia move passively in water currents to female gametophyte
Female gametophyte tip contains carpogonium (oogonium)
Fertilization occurs when spermatia land on trichogyne of carpogonium, producing carposporophyte
Describe the carposporophyte (2N) stage in the triphasic lifecycle of red algae.
- Carposporophyte (2N)
Not free-living, associated with female gametophyte
Fertilized carpogonium produces zygote
Zygote becomes carposporophyte (gonimoblast
filaments)
Carposporophyte produces 2N carpospores via mitosis in carposporangium
Carpospores produce the tetrasporophyte
Describe the tetrasporophyte (2N) stage in the triphasic lifecycle of red algae.
- Tetrasporophyte (2N)
Free-living
Carpospores germinate to form tetrasporophyte
Tetrasporophyte produces N tetraspores via meiosis in
tetrasporangium
Tetraspores germinate to form gametophyte
gametophyte vs carposporophyte vs tetrasporophyte
Gametophyte (N): free-living, male produces spermatia, female gametophyte tip contains carpogonium - combine to produce carposporophyte.
Carposporophyte (2N): Not free living, associated with female gametophyte. Carposporophyte produces 2N carpospores via mitosis in carposporangium, and the carpospores produce the tetrasporophyte.
Tetrasporophyte (2N): Freelving, results from germinated carpospores. The tetrasporophyte produces N tetraspores via meiosis in the tetra sporangium, which germinate to form gametophyte.
Why do red algae have a triphasic lifecycle?
- Because male gametes are nonmotile, triphasism is compensation for lack of motility, serving to enhance reproductive fecundity
- Carposporophyte and tetrasporophyte amplify fertilization events – one zygote nucleus can potentially produce billions of gametophytes
- Carpospore production increases number of tetrasporophytes produced
- Zygote is protected and nourished by gametophyte which increases its chances of successful germination and carpospores formation
How are red algae similar to fungi?
- Similar to Ascomycotina = “sac fungi”
- Nonmotile spermatia and the trichogynes occur in
Ascomycetes and many red algae
- Resemblance between diploid carposporophyte of some Rhodophyta and the ascogenous hyphae of Ascomycetes
- Thickening occurs in cross-walls of red algae and Ascomycetes
- Several species of Rhodophyta have lost their pigmentation making them parasitic, like fungi - Possibly implies common ancestry
___ algae are similar to ____ fungi.
Red algae are similar to ascomycete fungi.
What is mucilage (from the cell wall with agar and carrageenan) used for?
- Thickeners and stabilizers in food (ice cream, pudding)
- Pharmaceuticals
- Microbiological growth medium
Socio-economic uses for red algae.
- Widely used as food, often in aquaculture (bamboo sticks to trap floating spores) - ex. Nori
- Mucilages (agar and carrageenan) used as thickeners and stabilizers in food, pharmaceuticals, and in microbial growth mediums
Why is nori green?
Comes from red algae so has red pigment, but phycobilins are water soluble so the processing removes the red pigment (wash the algae).
Chlorophyll isn’t water soluble so it remains in the nori.
Why are green algae green?
-relative absence of accessory pigments for chlorophyll colour are unmasked
Endemic
things found only in specific locations
Largest class of algae
Bacillariophyceae
Main pigments in green algae
Principal pigments: chlorophylls A and B
Accessory pigments generally low in concentration, including β-carotene and lutein (xanthophyll), some others
Name 2/3 algal groups with chlorophyll B
- Euglenids
- Green algae (chlorophyta)
- Glaucophyta
Number of chloroplast membranes in green algae and what this means. How many thylakoids, and are they stacked?
Chloroplast surrounded by two membranes, no chloroplast endoplasmic reticulum as in some “lower” groups
- Implies primary endosymbiosis
Thylakoids stacked in groups of 2-6.
Storage product of green algae and where it’s stored/formed
- starch is primary reserve, formed inside the chloroplast
Flagella of green algae
- Isokontous (same)
- Whiplash / smooth / acronematic
- Some fine hairs
Cell walls of green algae
if existing, complete and made of cellulose, usually without outer gelatinous pectin layer.
- may not have cellulose, variations:
- Some have glycoprotein cell wall
- Sometimes a lorica
- Some deposit calcium carbonate on wall exterior
What are the two types of cytokinesis?
1) phycoplast
2) phragmoplast
Heterotrichous
Filamentous morphology, differentiated into erect and prostrate parts
Siphonous/coenocytic
multiple nuclei in one cell
Glycoproteins
mixture of carbohydrates and proteins, in green algae (order volvocales), doesn’t have cellulose in this case
Phycoplast
- “algae made”
- more primitive (in simpler forms, chlorophycean line)
- two daughter nuclei close together
- after mitosis division, spindle fibres disappear and are replaced by more microtubules perpendicular to plane of division
- new cell wall forms across microtubules by furrowing (ingrowth of cell membrane) or cell-plate formation (outward growth from centre)
Phragmoplast
- “wall made”
- most advanced, found in higher green algae and more advanced plants (Charophycean line)
- after mitosis division, two daughter nuclei held far apart by persistent spindle fibres perpendicular to plane of division
- Golgi vesicles aggregate on spindle fibres and form new cell plate via furrowing or cell plate
Eleutheroschisis
daughter cells synthesize their own cell wall (don’t use parent cell wall)
Eleutheroschisis vs Desmoschisis
Eleutheroschisis: daughter cells synthesize their own cell wall (don’t use parent cell wall)
Desmoschisis: cell wall of daughter cells is in part composed of the parental wall (recycling of parental wall)
Desmoschisis
cell wall of daughter cells is in part composed of the parental wall (recycling of parental wall)
Cell wall of green algal order Volvocales
glycoprotein - mixture of carbohydrates and proteins, in green algae (order volvocales), doesn’t have cellulose in this case
- some have lorica
- but NO cellulose
Eyespot (modification) in green algal order Volvocales
Some with eyespot INSIDE chloroplast and photoreceptor in plasma membrane above eyespot
Which of these 2 cell division mechanisms is found in these orders of green algae?
- Oedogoniales
- Volvocales
- Chaetophorales
- Chlamydomonas
- Chlorococcales
Eleutheroschisis or Desmoschisis
Eleutheroschisis:
- Volvocales
- Chlorococcales
- Chlamydomonas
Desmoschisis:
- Chaetophorales
- Oedogoniales
In the 1900s, what did Blackman hypothesize?
-hypothesized evolution of Volvocales was analogous to evolutionary progression in development of multicellular, terrestrial plants
○ Trends
- Increase in colony size and number of cells
- Change in morphology from flat plane to hollow sphere
- Increase in reproductive specialization
- Change from isogamous to oogamous sexual reproduction
2 things found in high nutrient waters
nitrogen and phosphorous
Which are the three most common algae in Manitoba?
Diatoms, Green Algae and Cyanobacteria
Polarity
Anterior-posterior gradation in cell size, eyespots (larger in anterior), coordinated directional swimming and formation of specialized cells
- Having distinct ends to cells
Palmelloid stage (in green algae, order Volvocales)
-when motile forms lose their flagella during certain phases of the lifecycle
Agglutination
In green algae, order Volvocales (ex. chlamydomonas)
- cells clump together
- Flagella used to ensure chemical compatibility, and if two cells are compatible, then the flagellae will agglutinate to bring the two vegetative cells together (make sexual reproduction easier)
Agglutinins
gamete compatibility recognition
Quadriflagellate planozygote
motile zygote with 4 flagellae, in sexual reproduction in chlamydomonas
Photoheterotrophic
in green algae
- use organic carbon only when light available and when limited by dissolved inorganic carbon supply
- require light to photosynthesize but use organic carbon to break into inorganic form then use photosynthesis (don’t use carbon dioxide as their main source of carbon)
Phototactic movement and the flagella
- measures light at different time intervals as cell changes its position relative to light
- photoreceptor of the eyespot contains chromophore (coloured substance)
Pseudograna
- pancake stacks of thylakoids with some interconnection between grana
- resembles higher vascular plants
- areas stacked in columns by partial overlap of thylakoids
Conjugation
- sexual reproduction
- tube forms between two filaments and the contents move from one cell into another, to form the zygote
What is the role of sexual reproduction?
- response to adverse conditions, not for genetic variability
- allows to create specialized structures to reproduce
- possibly part of life cycle for some alga
When does a palmelloid stage usually develop?
If no water present, palmelloid stage develops; cells develop flagella when water returns
hypnozygote
In sexual repro stage of chlamydomonas:
- Gametes fuse at anterior ends, forming quadriflagellate planozygote
** Flagella lost, cell contents condense and thick walls forms, forming dormant stage – hypnozygote*
Under favourable conditions, hypnozygote germinates to form zoospores, released by wall breakdown
Gonidium, gonidia
- In green algae (order Volvocales)
- Large mass of specialized cells in parent colony (sexual reproduction)
- Produces daughter colonies by repeated mitosis within parental colony
- only the gonidia reproduce
Plakea
- In green algae, order Volvocales
- inverted colonies
- Start off with flagella on the interior of the colony during both sexual and asexual reproduction, but a mechanism causes all the cells to invert so now flagellae or on the outside of the colony
Motility in Order chloroccales (green algae) + adaptions
- Vegetative cells nonmotile (no flagella and other structures associated with flagellated cells, such as eyespots and contractile vacuoles)
- Due to lack of motility, many genera modified to increase surface area and create drag (slow sinking):
elongated shapes, spines, plate-like or stellate colonies, may cluster together
Autocolony
a daughter colony formed within one of the cells of a colony and duplicating in the parent
- Parental cell contents used up, but wall is not reused so the daughters stay in the empty cell for a while
Lifecycle of green algae, order Volvocales
Non-colonial biflagellate
Haplontic lifecycle
2-16 daughter cells (zoospores) produced via mitosis of
parent cell (parental flagella lost before division)
Daughters form new cell wall while contained within parental cell (eleutheroschisis)
If water present, enzymes break down parental wall and release daughters, which develop flagella and enlarge
If no water present, palmelloid stage develops; cells develop flagella when water returns
In the order Chlorococcales (green algae):
- Cell wall composition
- Eleutheroschisis or desmoschisis?
- Motility
- Cell wall mostly of cellulose (NOT glycoprotein)
- Daughter cells synthesize their own cell wall (eleutheroschisis)
- No motility
In the order Chlorococcales (green algae):
- Reproduction (very basic)
Asexual via formation of coenobia (autocolonies)
Sexual, rare, is isogamous with fusion of motile gametes
In the order Chaetophorales (green algae):
- Habitat
- How many nuclei and chloroplasts?
- Most freshwater, some terrestrial; none marine
- Uninucleate cells with single, parietal, ring-like chloroplast
In the order Chaetophorales (green algae):
- Morphology
- All multicellular filaments, occasionally parenchymatous
- Some are heterotricfous, showing evolutionarily progression toward multicellular plants (eg. erect and basal filaments)
In the order Chaetophorales (green algae):
- Reproduction types and what happens to the daughters.
- Eleutheroschisis or desmoschisis?
- Daughter cells remain connected after division by plasmodesmata
- Cell wall of daughter cell is, in part, composed of parental wall (desmoschisis)
Asexual reproduction:
- Filament fragmentation
- Quadriflagellate zoospores that develop into new filament
- Sexual reproduction poorly known
In the order Oedogoniales (green algae):
- Habitat
- How many nuclei and chloroplasts?
- Basic morphology
- Freshwater, commonly epiphytic or epilithic, or
planktonic
- Cells uninucleate with several parietal net-like (reticulate) chloroplasts with numerous pyrenoids
- All are multicellular filaments (branched or unbranched)
Anisogamy
-during conjugation (sexual reproduction), one cell moves towards the other through the tube
Due to lack of motility, flagella, eyespot and contractile vacuoles, how do algae slow down their sinking?
-increase surface area and drag with spines, elongated shapes, plate-like or stellate colonies, sculpting outside the cell gives it buoyancy
Parthenogenesis
doesn’t involve the production of a zygote, the gamete forms an azygospore
Reticulate
net-like shaped
Stephanokont
ring or flagella near anterior end
Nannadrous vs Macrandrous
nannadrous: dwarf male filaments (increases likelihood of successful reproduction), attached to oogonium mother (epiphytically)
macrandrous: large male filaments
Circein
- a pheromone named after the Greek Goddess that attracts men
- attracts the androspore in green algae reproduction (O. Oedogonium)
- no new genetic combinations!
- enhance the likelihood of successful sexual reproduction
Ring scars
- in green algae reproduction (O. Oedogonium)
- distinctive flared edges at ends of original wall where it split during cell division
- Can count number of ring scars to find out how many times alga divided
Why is the Oedogonium (green algae, order Oedogoniales) reproduction called the tent-top camper?
- Cell wall ruptures and allows the cell to expand and recreates a new cell wall (expands and comes back down)
- Scars remain from this cell division (asexual)
Phycoplast vs Phragmoplast
Phycoplast: simpler algae’s microtubule structure during cell division (spindle breaks down)
Phragmoplast: in vascular plants, more advanced, involves microtubules during cell division (spindle persists)
Isthmus
- distinctive narrowing in the centre of the cell in desmids (constriction around the structure of the cell)
- during asexual division, the cell divides across the isthmus, but starts to expand outwards to form another semi-cell
Hormesis
what could be beneficial in one quantity, whereas not beneficial in another quantity (too much of a good thing is a bad thing)
Ex) too high temperature (and too low) is detrimental to algae growth)
Epilimnion vs Hypolimnion vs Metalimnion
Epilimnion: live at the surface of the lake, well illuminated, those that are photosynthetic (autotrophs)
Hypolimnion: at the bottom of the lake
Metalimnion: intermediate layer, allows for both light and higher nutrient level, best of both worlds, facultative heterotroph found here due to capturing the dying algae that are sinking towards the bottom of the lake= Metalimnion Blooms
Cercein
Pheromone produced by green algae, attracts male and only the presence of a male causes the female to produce an egg
Androspore
- Green algae reproduction stage (asexual)
- Thick walled resting change, can stay in this form until conditions change
- Germinates into thallus
Chrystalline cellulose
- some cell walls of green algae contains this
- differs from cellulose in its 3D linkage
- insoluble in water
- resistant to chemicals
- makes cell wall very robust
Codiolum
- Stage in green alga reproduction
- Similar to vegetative cell but has thicker walls
- Develops into a regular vegetative cell
Function of the holdfast or basal cells or rhizoids
anchoring
High nutrient water usually indicates what?
pollution
Spermocarp envelope
-protective coat structure for the zygote on the vegetative cell
Trichogyne
the long, colourless neck on the oogonium
Reproduction/life cycle in green algae (ulvophycea)
Haplontic lifecycle under climatic control
All cells reproductive except basal one
Thallus abundant at shorter day lengths (8-16 hrs) in shallow water along rocky shores of lakes in Canada and northern USA
When water temperature reaches 10°C, thallus disappears as it converts massively into zoospores
cells of filament act as sporangia and produce quadriflagellate zoospores which germinate into new filaments
Asexual also by filament fragmentation
Sexual under long day conditions (> 16 hours) with cells acting as gametangia and producing biflagellate isogametes (smaller than quadriflagellate zoospores)
Gametes produced from different filaments
Gamete fusion following by zygote production (planozygote) which undergoes resting stage or develops into 2N “codiolum stage”
Zygotic meiosis releases N quadriflagellate zoospore or aplanospores
Gametes positively phototactic; zygote negatively phototactic
Desmids or “Desmos”
linked or in chains (two halves bonded together)
Scalariform conjugation
-two seperate filaments form a sort of ladder and are connected by a conjugation tube (lateral line up)
Papilla
Protrusion of the wall form a bump then extend outwards to create the conjugation tube to connect the contents of the two filaments
- Conjugation canal formed by papillae between adjacent
cells
Placcoderm desmids vs Saccoderm desmids
Placoderm desmids: unicells constricted in middle to form two semi-cells with pores in cell wall for mucilage secretion (motile), has an isthmus
Saccoderm desmids: unicells not constricted into semicells, no pores in cell wall (nonmotile)
Amoeboid gametes
Naked protoplasts
Conjugation (distinct feature of green algae class Zygnematophyceae)
2 naked protoplasts (amoeboid gametes) fuse
* not gametes, no rigid cell wall
Scalariform vs lateral conjugation
scalariform (two separate filaments)
lateral (between cells of same filament)
How can an alga be isogamous vs anisogamous if it does conjugation as sexual reproduction?
In conjugation: protoplast from one cell moves through conjugation canal and fuses with other protoplast
- male to immobile female by amoeboid motion = anisogamous (ex. spirogyra)
- fusion occurs in conjugation tube between cells = isogamous (ex. cosmarium)
Oligotrophic water
low nutrient water
What is the common name of the Class Charophyceae?
stoneworts or skunkworts
Pseudofilaments
individual cells get stuck together due to mucilage (creates buoyancy)
Cosmarium asexual lifecycle (basic mechanism) - is it Eleutheroschisis or Desmoschisis?
- Cell division (mitosis, cytokinesis) at isthmus, resulting in two daughter cell, each inheriting one semi-cell from its parent, and generating one new semi-cell (desmoschisis)
- No zoospores
Sexual reproduction in Cosmarium
- Haplontic, isogamous lifecycle similar to Order
- Zygnematales (conjugation)
- Cells pair in mucilage, aligned at right angles to each other
- Cells split at isthmus with gametes moving out via amoeboid motion
- Gamete fusion produces thick-walled zygote
- Zygote germination produces 2N protoplast which
undergoes meiosis to produce four 4 cells
- Each takes the form of normal desmid
Where do most green algae live in?
nutrient rich environments
Corrugations
small filaments on the exterior periphery of the filament in green alga class charophyceae
What is on the exterior of the cell wall of Charophyceae (stoneworts)?
deposits of CaCO3 (calcium carbonate) called marl, created during photosynthesis
Nucule vs Globule
- reproductive structures
- located at the axial
- has a sheath of sterile cells (unique for algae) surround the globules produced at nodes on lateral branches
- nucule=female
- globule=male
Endozoic
living inside animals
What are the socio-economic uses of Chlorophyta?
○ Chlorella grown commercially in Asia as health food supplement
○ “Green Plant Juice Blend” Has Spirulina, Chlorella *
○ Dunaliella and Haematococus sources of carotene for food colouring and pharmaceuticals
○Enteromorpha and Ulva consumed in Pacific region
○ Primary production in freshwater and marine ecosystems
** ○ Useful for physiological studies pertinent to higher pants (ex-carbon fixation), similar metabolic pathways but easier to grow in lab
○Nuisance growth in high-nutrient environments
What were the results of the Fort White Diatoms Frustule Count?
- Lake today is becoming eutrophic=more diatoms
- Double the amount of phosphorus today
- High peak in chlorophyll today
- Trend where two peaks of lots of diatoms
Nuclei and chloroplasts in green algal class Charophyceae
- Typically very large cells start uninucleate and become multinucleate (siphonocladous)
Asexual reproduction in green algal class Charophyceae (method and also phycoplast or phragmoplast)?
- Mitosis with persistent telophase spindle (phragmoplast) with cell plate formation during cytokinesis
- Cell division (mitosis, cytokinesis)
- No zoospores
Sexual reproduction in green algal class Charophyceae
- Flagellated cells produced during sexual lifecycle (biflagellate sperm)
- Haplontic, oogamous lifecycle
- Female oogonia (nucules) and male antheridia (globules)
produced at nodes on lateral
branches, surrounded by sheath of sterile cells (unique for algae)
- Each globule releases 1000s of spermatozoids (antherozoids)
- Each nucule produces 1 egg - Antherozoids swim to nuclei and one fuses with egg
- Zygote forms thick wall and can remain dormant in sediment for long periods
- Germination involves meiosis, loss of 3 daughter nuclei, producing 1 new N thallus
Name the factors in algal distribution and abundance.
- Physical: Light, Temperature, Spatial Relations
- Chemical: Nutrients
- Biological: Herbivory, Allelopathy, Parasitism
Measuring PAR (photosynthetically active radiation)
- Secchi Disk Depth used to measure it
- Photic zone roughly 3X Secchi depth
- Invented by Italian astronomer Pietro Angelo Secchi, scientific advisor to the pope, in 1865 for water clarity measures
- Deeper you lower the disc, note at what depth you can no longer see it
- Light reflects off the disk
- Can also measure using a light meter to get direct measurement of PAR
Allelopathy
Chemicals produced by 1 plant is toxic to another plant
Chemicals from alga that negatively affects: Growth of another alga
Its own growth (autotoxicity)
Other microorganisms
Higher plants
How does water quality and quantity change with depth?
- water absorbs light, so less at the bottom
- most penetrative light is at the visible spectrum (which is used for photosynthesis)
- plants are mostly protected from UV in water
- huge loss of light with depth (virtually none by 10, 20m in most cases)
- red algae can use infrared light so gives them an advantage
If Secchi disk depth is 20cm, how deep can plants grow (max)?
60cm (it’s 3x secchi length)
Plants can live up to __% PAR
1%
PAR
Photosynthetically active radiation (part of visible spectrum algae can use for photosynthesis, 400-700nm)
How Secchi disk depth is recorded
- A metal disk painted black and white is lowered into water until you can’t see it, telling us that no more light is being reflected back for us to see
World record for secchi depth
Crater lake, Oregon
- Volcanic explosion created crater, very clear, bright blue water that gets a lot of incident light
- secchi depth of 20-43.5 m (plants can grow up to 130m!!)
Measuring PAR using flat or spherical sensors (mechanism)
- Sphere: looks like a lightbulb, measures light coming from above, the sides, and below (reflection/scattered light)
- Flat is the same but only measures light above.
Incident vs diffuse light
- Incident is light coming from the sun (like in Crater lake, Oregon), can use flat sensor to measure it.
- Diffuse light is scattered off from sediment, algae, plants, animals, etc. and is common in murky lakes (like fort white), so would need to use a spherical sensor to measure it.
Phytoplankton
suspended in water
Periphyton
attached to surfaces
What is the relationship between water and light and temperature?
Direct: Regulation of photosynthesis
Indirect:
Influence on thermal regime
-The more light, the warmer the water gets
- Lake stratification
- Warmest at surface because more light so less mixing
- Warm water decreases gas solubility (CO2, O2)
- Water circulation patterns with effects on nutrient cycling and distribution of chemicals → can be barrier to movement between cold and warm water
- Phototaxis and other behavioural effects (alga with eyespot, can move closer to light if needs more or further away when it needs less)
What is the relationship between solubility of O2 and CO2 vs temperature?
- O2 and CO2 are inversely soluble vs temperature
* warm water holds less gases
Importance of light : Direct Reasons
- Regulation of photosynthesis
- More light = more photosynthesis
Compensation point
Compensation point: where photosynthesis offsets respiration (=), where growth is 0, not enough light for photosynthesis, this point is not the same for all organisms
Importance of light : Indirect
- Influence of light on thermal regime (lake stratification)
- Gas solubility
- Metabolic rate
- Water circulation patterns with effects on nutrient cycling and distribution of chemicals
- Phototaxis and other behavioural effects
- The warmer water gets, the faster the metabolism activity
- Use of light with eyespot
What is the relationship between growth rate and temperature in…
- Suboptimal temp range:
- Optimal range:
- Inhibitory range:
- Suboptimal temp range: +, increases growth
- Optimal range: growth maximized (straight line on graph)
- Inhibitory range: decreased growth
Photic zone
- lighted part of the water (sufficient light to allow for photosynthesis)
- 3x the secchi disk depth
Water column
vertical column from the surface of water all the way down
Name some algal strategies to maximize light capture
*not critical
- Alter position in water column (flagella, gas vacuoles)
- Alteration of position and orientation of chloroplasts
- Increase in surface area to volume ratio (spines)
- Heterotrophy (if possible)
- Chromatic adaptation (pigmentation)
- Cyanobacteria are really good in high nutrient, high light waters due to having gas vacuoles enabling them to go up and down the water column
- Parietal chloroplasts can maximize light capture compared to axial chloroplasts that aren’t as good
- Low light algae have adapted to light deficiency (low Ik value), do this by altering their pigments (composition and quantity)
Why is temperature important for algae : Direct
- Regulation of metabolism and photosynthesis
- Stimulus for sexual reproduction (too hot or too cold)
- Affects algal buoyancy (max density at 4C)
Why is temperature important for algae : Indirect
- Affects water circulation patterns due to effects on density (stratification)
- Affects solubility of gases, mixing of nutrients
In a graph with temperature vs growth, where is inhibitory temperature range,suboptimal temperature range and optimal temperature range located on the graph?
suboptimal=upward sloping
optimal=peak that is constant
inhibitory=downward sloping
Q10
- Ratio comparing metabolic rate at one temperature with its rate at temperature 10 degrees Celsius
- Q10 = (rate at temp+10 degrees Celsius) / rate at temp)
- Often, Q10=2
**MR doubles with a 10C increase
How does sedimentation negatively affect algae?
- Most phytoplankton cells have density heavier than water (1g/mL)
- So the algae sink
- Sedimentation affects them negatively because it reduces light for photosynthesis
How to deal with sedimentation: Water motion (LIST only, the 3 ways)
1) Wind-driven convection (Langmuir cells)
2) Seiches
3) Water column turnover
Langmuir cells
=wind driven convection
- caused by the wind where water starts to rotate, creates water motion (one “line” goes clockwise, other goes counterclockwise)
- upwelling=algae pulled up to the surface
- downwelling=algae pulled to the bottom
Parallel windrows visible on water surface
Spiral movement in direction of wind
Minimum 11 km/h needed for formation
Cells concentrated in upwelling zones between rotating water masses
Seiches
- “Wind tide”
- Horizontal movement from upwind to downwind side of lake basin
- H2O level randomly and rapidly changes with the wind
- Vertical movement as epilimnion oscillates back and forth during and after wind activity
- Causes vertical and horizontal mixing of water column
Water column turnover
- Raises non motile, sinking algae and may trigger algal blooms
(mixed twice a year in spring and fall, in spring when ice breaks up)
-Helps move algae up and down, like in the spring it is brought back up to the surface and begins to thrive
How to deal with sedimentation : Small cell size
- Sinking velocity inversely correlated with ratio of cell surface area to volume (S/V)
- Cells with lower S/V sink faster
- Smaller cells sink more slowly than larger ones
- Filamentous or colonial organisms sink faster than unicells because they have less surface area with the same mass (***unless Colonies have less surface area and sink faster, so big spaces in the middle allows them to sink slower
- Hydrodynamic drag: More surface area, the slower the rate of sinking
Hydrodynamic drag
More surface area, the slower the rate of sinking
How to deal with sedimentation : Reduce cell density
- Store relatively light fats and lipids (don’t take up as much volume)
- Store photosynthetic products and turn into something more compact gives it more density advantage (like lipids)
- Mucilage can help prevent drying out, but also to sink more slowly since it’s mostly water, so it has same density as water (lightens the cell, so sinks more slowly)
- Gas vacuoles only in Cyanobacteria allows for floatation, explains why there are blooms (has a competitive advantage)
How to deal with sedimentation : Form resistance
- Spines and horns help to prevent sinking
- Teardrop shapes sink more rapidly than spheres
How to deal with sedimentation : Motility
Dinoflagellates are very fast!
Since viscocity and density are inversely correlated to temperature, what is the conclusion to the sinking rate of algae?
*not critical
Sinking rate will increase with increasing temperature
What are a periphyton’s spatial architecture?
- Positive means of attachment
- Mucilage used to attach to surfaces
- Stalks can help take advantage of light and nutrients that are usually shaded by the bigger algae
- Lights and nutrients diminish as you go down, so at the bottom usually mixotrophic
Successional processes
- Accumulation of biomass
- Change in species composition resulting from competition for light, CO2, nutrients, attachment space, safety from grazing
- occurs everywhere over time. Things will move in to colonize and then other species will go. Many alga grow upright (decreased competition for light and nutrients but then competition with other organisms at the top… it’s a trade off).
- things get increasingly complex, driven by competition
What is the equation for growth based on periphyton’s spatial architecture?
G=I+R-M-E-C G=growth I=immigration R=reproduction M=Mortality E=Emigration C=Grazing
What 2 things can you look at to see if an alga is a good nutrient competitor?
• Low KS or KQ – able to achieve high rate of growth at low concentration of the growth- limiting nutrient
• High μmax – able to achieve high rate of reproductive output
• So a “competitive index” is ratio of μmax to KS (Healy index); higher the value, better the
competitor
Example of parasitism of algae by a fungi
- Kitrid fungi produces zoospores that parasitize diatoms (preferentially Asterionella)
- Colony numbers of alga related to density of fungus
- infection is temp dependent, they like warmer water
Why are algal blooms bad aesthetically? What 2 chemicals produced by cyanobacteria smell bad?
Constituent species may produce chemicals that
impart taste or odour to water at ng/L levels (extremely low level)
Chemicals are probably secondary metabolites that serve no real role in metabolism, and may simply be waste products
At least five chemicals responsible for taste and
odour problems, most common of which are
geosmin and methylisoborneol (MIB)
Algal bloom problem: oxygen
When blooms collapse, they decompose, removing oxygen from the water column, leading to fish death (summerkill)
Decomposition may also occur in the winter, under
ice, leading to winterkill
Algal bloom problem: toxins
- ex. cyanobacteria, diatoms, dinoflagellates
Dermal and oral uptake
Typically low absorption in gastrointestinal tract
of humans and other mammals
No known antidote or method of removal from
contaminated water
Mostly liver or nerve toxin
Sublethal symptoms include vomiting, diarrhea, abdominal cramps, headache, excessive bronchial secretions, difficulty breathing, loss of equilibrium, coma, permanent (irreversible) memory loss
Why might Cyanobacteria have a competitive advantage in algal blooms?
Oldest, most adaptable algal group on Earth
Well adapted to high water temperatures and low light intensity occurring in summer blooms
N fixation gives them advantage when N is low (but not all bloomers can
Gas vacuoles provide buoyancy which keep them
suspended in well-lit, surface water
Mucilage provides protection from grazing
Climatic factors favouring cyanobacteria:
Shallow mixing depth and greater turbulence
Higher water temperature
Longer water residence time (low water levels and lower discharge from lakes)
Lower water viscosity at higher temperature favours species with ability to regulate buoyancy
How do algae affect humans? (Why study algae - 5 reasons)
Atmospheric oxygen Nitrogen fixation Food Environmental indicators Lake blooms
Name 1 genera that commonly causes lake blooms.
Common genera include Microcystis, Anabaena, Aphanizomenon, and others
Occur when nutrient enrichment, especially N and P, favours excessive growth
List the 4 general features of algae.
- No differentiation of parts.
- Vegetative reproduction is common.
- Unicellular reproductive structures.
- Zygote germination (if sexual) is not on parent cell.
