Heterokontophyta Flashcards
Golden algae taxonomy
Phylum Heterkontophyta
Class chysophyceae
Phylum Heterokontophyta have what type of endosymbiosis
Secondary with red algae
Habitat of Chrysophyceae
Oligotropic (low nutrient) fresh water environments
Feeding of Chrysophyceae
-facultatively heterotrophic (mixotrophy) in absence of adequate light, or plentiful, dissolved food
-eat yeast, smaller eukaryotic algae, and starch grains, bacteria
-in low light, 80% of carbon from phagotrophic activity
Heterokont meaning
2 flagella
-tinsel (anterior)
-whiplash
Cysts of Chrysophyceae
Stomatocysts
-preserved in fossil record
-silica shell
-~100mya (Cretaceous)
-161 distinctive morphological stomatocysts identified in arctic peat
-cyst wall inside membrane
-silica deposits within coalesced golgi vesicles
-pore at apex plugged with polysaccharide
What type of rock can you find fossilized stomatocysts
Pyrite
Why are ancient fossils of stomatocysts found in marine environments but the class is freshwater?
Probably in ocean water, and estuary type of environment transported them to fresh water to be fossilized
Chrysophyceae pigments
-chlorophyll’s a, C1 and C2
-chlorophyll c is for photo system 2
-accessory and protective pigment: fucoxanthin (carotenoid) that gives golden colour
B-1,2 glucan, found in posterior vesicle
Chyrosolaminarin
Photosynthate and storage organelle of Chrysophyceae
Pyrenoids
Chrysophyceae mobility
-flagellar swelling contains electron-dense area called a photoreceptor
-eyespot under flagellar swelling inside the chloroplast
-tinsel and whiplash
Cell walls of Chrysophyceae are composed of
Cellulose, Loricas and silicified scales and walls
Lorica
Envelope of microfibrils around protoplast
-not generally attached to protoplast
Chrysophyceae reproduction
-isogametes structurally similar to vegetative cells
-zygotic meiosis
-female produce a pheromone to attract males flagellated cells to swim to female
-resulting zygote becomes a stomatocyst and loses its flagella
Stomatocysts can result from _______
Asexual or sexual reproduction and are indistinguishable
Freshwater ________ are commonly used as in dictators of the environmental conditions during the deposition of the sediments
Stomatocysts
How do Chrysophyceae indicate environmental conditions?
-Indicate low levels of pollution
-high phosphate decreases populations
-prefer low pH related to their acid phosphatase enzymes that liberate phosphate from organic compounds and give advantage in low nutrient areas
-seasonal cold and oligotrophic conditions protect from predation
Fires give more nutrients so less Chrysophyceae
Class Bacillariophyceae are known commonly as….
Diatoms
Diatoms habitat and feeding
-almost every aquatic habitat as free-living photoautotrophs, colourless heterotrophs or photosynthetic symbiotes
Most numerous aquatic eukaryotes are
Diatoms
Most important aquatic primary producers are
Diatoms (25% of global PP)
Diatoms habitat
-dominant in cold, nutrient rich waters (ocean upwellings) and circulated waters of fresh water lakes
-planktonic, benthic, periphytic, endozpic (in animal) or ectozoic (on animal)
Diatom Frustules
-contain 96.5% silica oxide
-Frustules are enveloped by organic skin of amino acids and sugars
-bio-silica structure have increased strength because of their organic-inorganic microstructure
-silica walls accumulate in sediment (bio indicator)