Isogamy

Both Gametes are morphologically the same size

They may be physiologically different if so referred to as "+" and "-"

Oogamy

2 gametes are physiologically and morphologically different

Larger one loses its flagella, contractile vacuole and eyespot

Smaller one keeps its flagella, nucleus and small amount of cytoplasm

Usually have specialized gametangia that are UNICELLULAR - antheridium/spermatangium  and oogonium

Anisogamy

One of the gametes is smaller but they are morphologically the same otherwise

Larger is female smaller is male

WHAT TYPE OF SEX REP IS THIS?

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ANISOGAMY

WHAT TYPE OF SEX REP IS THIS?

[image]

OOGAMY

WHAT TYPE OF SEX REP IS THIS?

[image]

ISOGAMY 

What is a stramenopile?

Heterokonts - 2 flagella of unequal lengths that are different 

present in chrysophytes, diatoms, brown algae and oomycetes

-all have it at some point in there life

[image]

They all are protists

Diatom 

Distribution

 More common in Marine Water but also is found in Freshwater

Major component of Phytoplankton

More common in cold water and ice

Most abundant organisms in ocean

1 L of Water - 1 million diatoms

1cm2 of rock - 30-50 million 

Diatom Pigments

Chlorophyll A, Chlorophyll C, Carotenes, Xanthophylls, fucoxanthin (brown color)

Diatom

Storage Product

 chrysolaminarin (oil)

What is Diatomaceous Earth?

Build up of Diatom Cell Walls

used for : Insecticides, filtration in swimming pools, antibiotics,sugar, beer, wines, insulation highway line paint and reinforce rubber

What is the historic Morphology of Diatoms?

100 mya

during Cretaceous era

Morphology of Diatoms

 cell walls and how they grow

unicellular and colonies 

eg. filamentous colony - Melosira

Cells have 2 overlapping walls-theca

[image]

Morphology of Diatoms 

 cell walls and fossils

Cell Walls impregnated with Silica(resistant to decomposition)- good protection against herbivores

Make great fossils also architecturally diverse--> great paleoclimatic data 

Symmetry of Diatoms 

Pennate- Bilaterally symmetric - 2 large chloroplasts & Raphe-secretes slime for movement

Centric-radially symmetric- No raphe,no movement, numerous small chloroplasts

Reproduction of Diatoms

Asexual

Cell division/ mitosis

some cell lines get smaller over time --> solved by sexual reproduction where gametes are produced released into water (wall-less) fuse to form a zygote, grows to adult by forming a cell wall- leaves it vulnerable to be eaten

Auxospore formation-protoplast is released into water and its cell wall is regrown.

Reproduction of Diatoms

Sexual

Diplontic Life cycle

Name some examples of Diatoms we have seen

Diatoms are part of the Bacillariophyceae Class

pennate and centric types

Brown Algae

General Information

CLASS PHAEOPHYTA 

They are brown seaweeds

They are all photosynthetic

All are multicellular (most are macroscopic)

Brown Algae

General Information

storage product

pigments

transport organelles

Storage is laminarin

 All contain-Chlorophyll a, chlorophyll c, fucoxanthin- brownish color

Are Giant Kelp so they have sieve tubes that transports carbs to the base

Brown Algae

Distribution

Vast majority : rocky marine shoreline , cold water --> intertidal zone

Giant Kelp are the exception- they are cold marine but deeper 

Can be up to 150' deep

Brown Algae

Sargassum

Sargassum is a brown alga that exists in huge floating mats in the open ocean ; it helps increase primary productivity

Sargasso sea, gulf stream- oval shape of seaweed in North Atlantic

Derived from Portuguese word Sargaço= seaweed

Laminaria

Be able to draw one

and label holdfast , stipe and blade

Fucus

Be able to draw one 

and label blade and air bladders 

Reproduction in the

Order Fucales( Fucus, Sargassum)

Asexual

 Sargassum-Fragmentation

Reproduction in the

Order Fucales( Fucus, Sargassum)

Sexual

Has a life history different than all other brown algae

Diplontic and Oogamous 

 [image][image]

openings in receptacles --> conceptacles

inside conceptacles are gametangia

antheridium-produces sperm

oogonium-produces egg

If both sex organs are on one individual =monoecious

If each individual are on the sex organ= dioecious

Ripe eggs released in water-> fertilized by sperm -->zygote -> adult

Reproduction in the rest of the Brown Algae

-all produce zoospores

sexual reproduction- Alt. of Gen.

eg. Ectocarpus- gametophyte and sporophyte look the same; use genetic analysis to tell them apart

Isomorphic Alternation of Generation

eg.Laminaria- clear difference between gametophyte  (microscopic) and sporophyte (macroscopic)

heteromorphic alternation of Generation

Human Interests of Brown Algae

1. Once an important source of K and I

Iodine-cure for goiter- enlarged and atrophic thyroid gland

midwest of US- goiter belt Iodine poor soil and Nepal

2. Food for domestic animals

3. Fertilizer

4. Fucus- makes red dye for textiles

rouge by Roman Ladies

5. harvest kelp-huge amounts today

important in food production

6. Algin - prevents formation of ice crystals in ice cream

7. Stabilizes- icings, candy, marshmallows, mayo, cheese

8. Paint- reduces brush strokes

9. Sausage casings

For Alga-provides toughness and flexibility -> withstand waves

Green Algae

Phylum and Lineage

Phylum is Chlorophyta

green algae and plants form a monophyletic lineage

Green Algae

General Distributions

Attached to 

-Green Algae live in a wide range of habitats

-90% are freshwater - can be free floating or free swimming

-They are usually attached to substrates: mud , rocks, logs, shells, turtles, other algae and plants

-endozoic in protozoans, coelenterates (jellyfish, corals,hydras), sponges, lichens

- They can also be attached to soil, bark, airborne (dust) and snow-"watermelon snow" carotenoid pigments make it look red (nutrients from wind blown dust)- protective against solar radiation

Green Algae

General Morphology

-Huge Diversity

- Simple unicells; large colonies eg.volvox and Multicellular

-Motile and Non-Motile

-Filamentous(both branched and unbranched)

-Parenchymatous(tissue like 3D)

-Siphonous (Large(possibly branched) cells that are multinucleate).

-usually have 2 flagella of equal length

-Most have a cell wall with Cellulose(connects them to plants)

-Pigments include: chl a, chl b, carotenoids and xanthophylls (connects them to plants)

-Often have an eyespot

-Freshwater have a contractile vacuole

Green Algae

storage product

starch-stored in pyreoids- clear areas in the chloroplasts

Green Algae

General Reproduction

Asexual

Cell Division Mitosis , Fragmentation, spores, daughter colonies

Green Algae

General Reproduction

Sexual 

Different green alga have the 3 life cycles and gamete types

What are the 3 classes of Green Algae?

Chlorophyceae, Ulvophyceae, Charophyceae

Green Algae

Chlorophyceae

Chlorophyceae 

- largest group of green algae

-mostly freshwater

-all are haplontic

-flagella:2,4 or many more

eg. Chlamydomonas

~about 500 species

~motile unicells

~no cellulose

[image]

Green Algae

Chlorophyceae

~Chlamydomonas

Palmella stage

1.Chlamydomonas reabsorbs the flagella 

2.Chlamydomonas grows a gelatinous sheath around it

3. Gelatinous sheath grows to cover many chlamydomonas (Palmella Stage)

4. Chlamydomonas returns to non flagellated stage

Doesn't always occur in unfavorable conditions

Thought the palmella stage became fixed as part of life history-> evolution of colonies

Order of Volvocales

Volvocine Line

Intermediate steps between unicells and large colonial Volvox are preserved in loosely colonial forms

[image]

Coenobium

Colony in which the number of cells is fixed, the arrangement of cells is genetically determined almost each cell is morphologically very similar to chlamydomonas

Volvocine Line

Gonium

4 or 16 cells

Moves with a jerky motion

Breaks apart fairly easily (traumatic)

Any cell can become a new colony

all eyespots are the same size

Volvocine Line

Pandorina

16 Cells

all the cells become new colonies

cells on one side of the colony have larger eyespots

beginning of polarity

shivery movement

Volvocine Line

Eudorina

32 Cells

ball shape

Volvocine Line

Pleodorina

32 or 64 cells

circular

moves in rolling ball motion

Larger cells-small or no eyespots

smaller cells-large eyespots

only the large cells can form daughter colonies

Volvox

Circular and large

512 to 50,000 cells in the colony

-almost all cells are similar to chlamydomonas

-held together in a gelatinous matrix

-reproduce sexually and asexual through the formation of daughter colonies

-develop from the same side of the colony--polarity

-Daughter colonies have the same number of cells as the parent they are just smaller and packed tighter

General Trends in Volvocine Line

As you go "up"

1. Increase in cell #

2. Increase in Polarity as represented by

a) cell size differences

b) eyespot size differ

c) Distribution of daughter colonies

d) Increased directionality-> More like ball rolling

Sexual Reproduction

Gamete types

Gonium and Pandorina- Isogamous

Pleodorina, Volvox- Oogamous

Asexual Reproduction

1. There is a gonidium inside the parent matrix

2. Gonidium divide in half vertically (towards center )

3. Gonidium divides horizontally

4. Obligate divisions - cell becomes circular

5. at 16 or 32 cells ; a hollow sphere forms with an opening(phialopore)- some cells pop out

6. Cell inverts to now flagella are on the outside; popped out cells are now inside; phialopore seals up 

7. An enzyme is released that dissolves the parent matrix -> daughter colonies escape