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Flashcards by james.mcknight19, updated more than 1 year ago
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Created by james.mcknight19
almost 11 years ago
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| Question | Answer |
| What is Algae | Photosynthetic organisms, Eukaryotic Protist |
| Algae are not plants | They have different reproductive features |
| What Algae need | Carbon, Nitrogen, Phosphorous, silicon (not all), metals. C:N:P= 106:16:1 (moles) |
| Algae are subject to extreme environments | intertidal zone - large fluctuations in humidity, temp, salinity and light. Polar algae - months of darkness and sub zero temp |
| Plankton | organisms that are free floating and at mercy of current |
| Phytoplankton | photosynthetic algae and cyanobacteria |
| Zooplankton | heterotrophic plankton (tiny crustaceans, heterotrophic protists, bacteria, larvae) |
| Blooms | In unpolluted water phytoplankton is kept in control by seasonal changes, nutrient levels and predation but human interference and pollution leads to algal blooms |
| Blooms (2) | blooms correlate to the release of toxic compounds. Evolved as a defensive mechanism. can lead to massive die off of marine life. |
| Importance of CO2 | CO2 is used for both photosynthesis and in the transformation of CO2 to CaCO3 which is used to make coccolith scales (emiliania huxleyi) |
| Algal Groups | Dinoflagellates (Dinophyta) Haptophytes (Haptophya) Diatoms (Bacilliarophyta) Brown Algae (Phaeophyta) Red Algae (Rhodophyta) Green Algae (Chlorophyta) |
| Dinophyta | Most unicellular biflagellates. flagella beat within two perpendicular grooves. spins like a top as it moves. 2000-4000 sp. both marine and freshwater |
| Gonyaluax polyedra | Armoured dinoflagellate responsible for red tidal blooms along California |
| Reproduction (dinophyta) | Permanently condensed chromosomes so were initially thought to be primitive. Now thought to be highly derived. Reproduce by longitudinal cell division, each daughter cell gets a flagella and half the theca which they then reconstruct. |
| photosynthetic pigments (dinophyta) | Many lack the photosynthetic pigments but those that do have them are usually chlorophyll a and c an carotenoids (mostly peridinin) |
| Carbohydrate food reserve | Starch |
| dinophyta flagellum | Their flagella beat within two grooves with one encircling the dinoflagellate like a belt and the second coming off perpendicular to it. |
| Dinophyta Armour | Most dinoflagellates have thick cellulose plates called theca which are formed by vesicles of cellulose just under the outer membrane. |
| Dinophyta nutrition | 50% of dinoflagellates lack photosynthetic ability and must ingest solid food or by absorbing dissolved organic particles. Some photosyntheitc species also do this and these are known as mixotrophs. Some use a long tube and suck up organic material this is a peduncle or others use a cytoplasmic veil called a pallium. |
| Symbiosis (dinophyta) | often live in symbiosis with sponges, jellyfish, coral, giant clams, octopus. Whne living in symbiosis they lack theca and are called zooxanthellae |
| Cysts (dinophyta) | When conditions are unfavourable dinoflagellates from non-motile cysts that fall to the sea bed. |
| Haptophytes | Diverse array of mostly marine phytoplankton 300sp, most diverse in the tropics. |
| Haptophytes (2) | distinctive feature is the haptonema, which is equal in length to the flagella but does not beat, is used to sense and avoid objects and possibly like a fishing rod. |
| Coccoliths (Haptophytes) | 12 or more different families of haptophytes form small flat scales of CaCO3 these are known as coccoliths |
| Emilliania huxleyi | perfect example of coccolith, also formed white cliffs of Dover |
| Photosynthetic (Haptophyta) | most are photosynthetic with chlorophyll a and c, some contain accessory pigment fucoxanthin. |
| CNN Haptophytes | some haptophytes produce dimethyl sulphide (DMS) which after UV degredation form cloud condensation nuclei (CNN) |
| Diatoms (Bacillariophyta) | They are heterokont - tinsel and whiplash. account for 25% of primary production on earth. greatest biomass and diversity with 100,000 sp. |
| Diatoms (2) | unique cell wall called a frustule made of silicon. The frustule is made of two overlapping parts like a petri dish. |
| Diatom Symmetry | Two types of symmetry, pennate -bilaterally, centric - radial. |
| Diatom reproduction | Mainly asexual, each daughter cell receiving half of the frustule. One will be smaller so the size of the population slowly decreases until critical level is reached and induces sexual reproduction |
| Diatoms resting cells | when conditions are unfavourable they form resting cells at the bottom of the ocean |
| Diatoms (3) | they are a primary food source in marine and freshwater habitats so are used in mariculture for oysters |
| Diatoms phtosynthetic | most autotrophic containing chlorophyll a and c, with accessory pigment fucoxanthin. |
| Diatom Plastids | Pennate - 2 large plastids Centric - numerous discoid plastids |
| Diatoms food reserve | lipids and chrysolaminarin |
| Red Algae (Rhodophyta) | most abundant in tropical waters. 4000-6000 sp, fewer than 100 in fresh water. Lack centrioles and flagella |
| Red algae (2) | some have lost chlorophyll and are now parasitic. main food reserved are granules of floridean starch. |
| Red algae photosynthetic | Chlorophyll a is masked by phycobilins. The pigment is well suited for absorption of green and blue light. |
| Red algae cell wall | inner part contains cellulose microfibrils. outter layer usually having a mucilaginous layer such as agar. |
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