AqBot: Sexual and Asexual Reproduction Cycles and Coccolith and Frustule formation ONLY

Coccolith formation

1. Occurs in the golgi apparatus

2. calcite crystals will nucleate around an organic template called the base plate => the ring of calcite crystals will be evenly distributed to form a protococcollith ring

3. the calcite crystals extend outwards and interlock sideways

4. the protococcolith ring will mature and be exocytosed to form with the coccosphere which is the accumulated exoskeleton of previously formed coccoliths

5. CO2 produced during this process is being sent up to the chloroplast for photosynthesis, so it’s very efficient

Frustule formation

1. the cell elongates and the nuclei divides

2. The plasma membrane will undergo invagination and fold in. Following this, golgi bodies will ascend to cell formation

3. parts of the golgi vesicles will fuse to form the silicalemma this acts as a temporary membrane and serves as the vesicle to form frustules

4. silica will be deposited to form valves and the vesicle will accumulate near 1st girdle band

5. the 1st girdle band is formed and secreted out, the internal silicalemma turns into a new plasmalemma while the outer/old plasmalemma is lost

6. this is repeated for the # of girdle bands needed. Additionally, after each formed band, diatom size will decrease because the frustules are fitting together causing one daughter to be the same size as the parent while the other daughter is smaller

Cyanobacteria

• describe asexual reproduction? what specific group undergoes it?

• describe resting stage(s)

• describe sexual reproduction

• Asexual: fragmentation

  • Hormogonia = in truly filamentous cyanobacteria which can break off and glide away to develop into a new filament.

  • Baeocytes = similar to endospores produced inside the cell, multiple divisions w/in protoplasm bursts open the cell to release and mature.

• Resting stage: aka akinetes = thickened cell walls resistant to freezing and desiccation so can survive for months

• NO sexual reproduction

Rhodophyta

• describe asexual reproduction?

• define 3 important terms

  • carposporangia

  • tetrasporangia

  • trichogyne

• describe sexual reproduction? what specific group undergoes it?

• Asexual: fragmentation

• Terms

  • 2N Carposporangia = specialized reproductive structure in red algae that produce diploid carpospores.

  • 2N tetrasporangia = specialized reproductive structure in red algae that produce haploid spores.

  • Trichogyne = elongated tip

• Sexual: Diplohaplotonic/Sporic/Triphasic 1) 2N carposporophyte = spermatium attaches to trichogyne => nuclei divides so that one moves up the trichogyne and the other moves down the carposporangia to fuse with the carposporangium nuclei => fertilization forms diploid carpospore => 2) 2N tetrasporophyte = carpspore moves to the tetrasporangia since it is the “seat” of meiosis and forms 4 haploid tetraspores => 3) 1N Gametophyte = the 4 tetraspores develop into vegetative thallus via mitosis to start growing

Chlorophyta

• describe asexual reproduction

• describe resting stage(s)

• describe sexual reproduction. what specific group undergoes it?

• Asexual: fragmentation

• Resting stage = hypnospores/hypnozygote

• Sexual for Ulva spp.: Diplohaplotonic/Sporic = 1) swarmers aka biflagellate, unisexual (either male or female) gametes are released from thallus to form cluster and then separate into mate pairs => 2) male and female gametes fuse their cells at anterior end so that 4 flagella are now present => 3) zygote settles (negatively phototactic), attaches by flagella, then flagella gets absorbed into the protoplasm and cell wall is secreted => 4) zoospores w/ 4 flagella are released via meiosis => 5) several days later a zygote germinates, rhizoid and blade cells form to get macroalgae

Euglenophyta

• describe asexual reproduction

• describe resting stage(s)

• describe sexual reproduction. what specific group undergoes it?

• Asexual: fragmentation and binary fission via longitudinal split

• NO sexual reproduction

Dinophyta

• describe asexual reproduction

• describe resting stage(s)

• describe sexual reproduction. what specific group undergoes it?

• Asexual: binary fission via oblique division so each daughter receives half of plates but unequal amounts of epicone and hypotheca.

• Resting cysts

• Sexual reproduction (triggered by environmental conditions). Gymnodinium spp. = 1) gametes form when vegetative cell is subject to short days at low temperatures (gametes and vegetative cell are very similar) => 2) gametes divide, swarm, copulate, and then fuse at sulcus to form a zygote which is also similar to vegetative cell => 3) epicone enlarges, transverse flagella and waste band are lost, and zygote rounds off to form hypnospores => 4) hypnospore mature in 48 hrs, plastids bleach, 2 nuclei fuse, and a thick endospore is secreted under the temporary exospore with spines => 5) after 4 weeks, hypnospore germinates, endospore is digested away, mucilage envelope develops, wall bursts, and swarmers escape => 6) swarmer (small vegetative cell) develops brown color, goes through 2 meiotic divisions and forms 4 haploid flagellates/daughter cells which grow up

Cryptophyta

• describe asexual reproduction

• describe resting stage(s)

• describe sexual reproduction. what specific group undergoes it?

• Asexual: DOMINANT

• Sexual: Not much is known about sexual reproduction for this group. Cryptomonas spp. => both 1N haplomorph and 2N diplomorph can reproduce vegetatively and the vegetative cells act as gametes

Heterokontophyta/Ochrophyta: Chrysophyceae

• describe asexual reproduction

• describe resting stage(s)

• describe sexual reproduction. what specific group undergoes it?

• Asexual: Dinobryon spp. => 1) vegetative cell enlarges and bulges out of lorica => 2) golgi forms vesicles for continuous silica deposition so that a silicified statospore wall forms => 3) small piece of cytoplasm outside of wall forms collar => 4) mature statospore has 2 nuclei, 2 plastids, and rich in energy reserve => 5) swarmers fly out of statosphere and mature in a male or female colony

• Resting stage: statospores = cysts in Chrysophyceae; can be spherical, ellipsoid, or oval; outer surface is smooth or ornamented w/ warts, spines, and arms; form from either vegetative cells or during sexual reproduction.

• Sexual: Dinobryon spp. = 1) after the female produces erogen the male colony will divide at the younger tip/tiers so that one male cell will remain in the lorica while the other will go to the female cell => 2) the male and female cells with orient themselves so their flagella are parallel, then they will fuse at anterior end of the lorica resulting in plasmogamy (cytoplasm of the parents fuse, but not the nuclei), overall a quadiflagellate planozygote (motile, diploid zygote) will form => 3) flagella are lost and zygote moves up the lorica mouth => 4) zygote will round at the mouth of the lorica and a binucleate statospore will form => 5) cellulosic vesicle will form a spark germination => 6) SOMEHOW meiotic cleavage results in 4 daughter cells

Heterkontophyta/Orchophyta: Bacilliariophyceae

• describe asexual reproduction

• define auxospore

• describe the gametes of the different diatoms

• describe sexual reproduction. what specific group undergoes it?

• Diatom - Chaetoceros spp. => 1) valves of parent become epitheca of daughter cell => 2) daughter cells produce hypotheca, one daughter cell will be the same size as the parent while the other daughter cell will be smaller => 3) when the daughter cell gets too small, ~30-40% of max adult size, sexual reproduction kicks in to increase the cell size.

• Sexual: sexual reproduction can also occur under certain environmental conditions (i.e., light, temp, nutrients, etc.) Chaetoceros spp.

• Auxospores = forms from the fusion of 2 gametes via meiosis; in centric and gonoid diatoms, the male gamete is motile while the female gamete is not; in pennate and trellisoid diatoms, there are non-motile gametes

• Sexual: Chaetrocerous spp. = 1) gametogenesis initiates due to temp and many meiotic events form 32 male gametes, which are released as uniflagellate swimmers => 2) male gametes lose flagella and attach to female gamete by swimming through the open valve to the inside of the frustule => 3) cell contents extrude and form auxospores => 4) auxospores will produce new cells with maximum size frustules => 5) daughter cells remain attached and undergo 2 divisions so that resting spores and produced and can germinate to produce larger cells

Heterkontophyta/Orchophyta: Raphidophyceae

• describe sexual reproduction. what specific group undergoes it?

• Sexual: Chattonella spp. 1) vegetative diploid cell grows by binary fission => 2) haploid cells prodcued under low nutrients, they change into resting cycts, and spend several months dormant in sediment => 3) swarmers germinate from the cysts and somehow (unknown) become diploid

Haptophyta - Emiliania huxleyi

• what are the 3 cell types

• how do they mainly reproduce?

• describe sexual reproduction. what specific group undergoes it?

• 3 cell types: coccolith, naked, and scaly

• mainly reproduce via asexual/binary fission

• Scaly cell may be gametes/sexually reproduce. ALSO "Cheshire Cat" escape = as a result of giant virus infecting diploid phases, the diploid scaly cell becomes a haploid phase to be unrecognizable to the virus while diploid info passed to the next generation