Lecture 2 Flashcards
which linaege had a probably loss of a primary plastid?
chromalveolata and excavata
Which lineage had a probable secondary gain of plastid from red algae
chromalveolata:
- stramenopila
- haptophyta
- cryptophyta
- alveolata
Which lineages had a probable secondary gain of plastid from green plants
Euglenozoa, chlorarachniophyta and part of dinoflagellata
What are exceptions in red algae which lost their secondary endosymbiont
apicomplexes, ciliates, oomycetes
Describe Euglenozoa (euglenphyta)
- flagellate unicellular protozoa -
- most closely related to kinetoplastids -
- chloroplast derived from captured green algae,
- 3 membranes on chloroplast
- food reserve: paramylon
- many species are heterotrophic
- sexual reproduction is unknown
What is the ecological importance of euglenozoa
mostly plantonic species
- typically floating in uppermost layer of water column
in freshwater, brakkisch water, common acid peatland
- ability to live in waters with pH to 1.0, optimum 3.0
Which linaege solely contains photosynthetic algae?
haptophyta
Describe dinoflagellata
- belonging to alveolatabut probably polyphyletic
- both phototrophic and heterotrophic as well as mixotrophic
- chloroplast with 3 membranes
- 2 unequal flagella
- giant nucleus with constantly condensed chromosomes
- very complex organelles
What is the ecological importance of dinoflagellates
- mostly planktonic species, major part of phytoplankton
- common outbreaks
- red tide, harmful algal bloom
- production of toxins: saxitoxin, brevitoxin, ciguatoxin
- often in symbiotic relations with cnidarians and others
- zooxanthelles
Principle characteristics of heterokonts like stramenopila
- major eukaryotic lineage of >100 000 spp.
- photosynthetic members commonly designated as brown algae – Chromophyta
- non-photosynthetic members of Stramenopila traditionally recognized as fungi
What are characteristics of chloroplasts of photosynthetic stramenopila?
- 4 membranes (probably originally algal)
- chlorophylls a, c (1, 2) fucoxanthin as accessoric pigment
- differentiated pyrenoid within the chloroplast
What are non photosynthtic members of stramenopila
- Oomycetes (water molds),
- Labyrinthulomycetes,
- Hyphochytridiomycetes and
- other small groups
principle characteristics of brown algae (chromophyta)
- mostly marine, large multicellular algae
- up to 2000 species, the largest may reach up to 60 m
- sometimes forming differentiated tissues
- paccessoric pigments β-carotene and fucoxanthin
- sexual reproduction, flagellated spores and gametes, both isomorphic and heteromorphic alteration of generations (sporophyte, gametophyte)
- laminaran, mannitol and oil as food reserves
- outer cell wall containing anionic polysaccharide algin
- alginates widely used in food, pharmaceutical, paper & textile industry…
- also used as a source of potassium carbonate, iodine, soda
What is the latin name for brown algae
Phaeophyceae
What is the latin name for diatoms
Bacillariophyceae
How many species are estimated for diatoms?
>100 000 spp. estimated
describe structure of diatoms
- unicellular, sometimes forming colonies
- silica cell wall (frustule);
- centric (radially symmetrical) or pennate (bilaterally symmetrical)
- most forms non-motile, only male gametes of centric diatoms possess a flagellum
- accessoric pigment fucoxanthin
what do diatoms use as food reserves?
chrysolaminaran, oil and volutin
What is the importance of diatoms?
- are one of the major carbon producers (up to 1/4 of earth primary production)
- key role in regulation of biogeochemical cycle of silicon
- fossilized oil can be produced (attempts to make it as source for industrial harvesting)
- diatomite (diatomaceous earth) – porous soft sedimemtary rock – filtration, mild abrasive, absorbent
What photosynthetic organisms resulted from a primary symbiontic event
- Glaucophyta
- red algae
What is a cyanelle
is a primary chloroplast (or rather endosymbiotic cyanobacteria)
What kind of algae are red algae?
mostly marine, both micro- and macroscopic, uni- and multicellular algae
- 5000 spp. estimated, <200 freshwater
describe structure of red algae
- chloroplast with 2 membranes, thylakoids unstacked with phycobilisomes
- no motile cells
- polar rings in place of centrioles
- have cell walls
What do the chloroplasts in red algae contain?
- chlorophyll a (also chlorophyll d in small quanities but this probably originates from associated cyanobacterium Acaryochloris
- phycobilisomeproteins as accessory pigments -> this causes the red colour
What do red algae use a food reserve?
floridean polysaccharides
How do red algae reproduce?
pcommonly reproducing sexually, alteration of generations
- (gametophyte, sporophyte [or carpo- and tetrasporophyte])
describe the cell walls of red algae
- microfibrils (cellulose/polysaccharide) and mucilaginous matrix (agar, carrageenan)
- slippery texture;
- Porphyra (‚nori‘ – Japanese term for this kind of edible seaweed); broad use of agar/carrageenan in food industry
- calcium carbonate deposits – coralline algae of coral reefs
- sometimes in extreme depths (268 m recorded!)
- fossils from Precambrian (>700 mya) – among the oldest fossilized algae
What are salient characteristics of chloroplastida
- chloroplast acquired by the primary endosymbiotic event (2 membranes)
- chlorophylls a & b, carotenes & xanthophylls as accessoric pigments, no phycobilins, thylakoids arranged in grana
- starch as the food reserve
- cellulose cell wall
- flagella usually two but same in structure (isokont), though sometimes differently long
What are the 2 main lineages of Viridiplantae
green algae (Chlorophyta, maybe paraphyletic) and streptophytes [Streptophyta]
Describe structure of streptophyta
- lineage that comprises some of the ‚green algae‘ plus all Embryophyta (‚higher plants‘)
- thylakoids in grana
- cell division often mediated by phragmoplast
- motile cells w/ 2 subapically inserted flagella (asymmetric), flagellar apparatus w/ ‚multilayered structure‘ and parallel basal bodies
- mostly land plants
Describe variability of thallus organization of chlorophyta
- flagellate unicells
- coccoids
- coccoid colonies
- coenobia
- filaments (branched, unbranched, heterotrichous)
- thalline
- siphonous
- siphonocladous
What is an apparent representative of chlorophyta
Lettuce like Ulva
- large group; extreme thallus complexity and cellular sophistication
- coastal and marine seaweeds but other habitats as well
- unicellular to multicellular filamentous, but typically thallose, giant-celled siphonous and siphonocladous
- easily cultivated, food source
- excessive outbreaks – production of H2S on decomposition
What is the role of chlorophyta?
phytoplankton and phycosymbionts of liches
Give a few facts about Zygnematophyceae
- largest charophyte group, > 5000 spp.
- only freshwater & terrestrial, no marine
- unicellular, filamentous and colonial
- only non-motile cells (including the gametes!)
GIve a few facts about Charophyceae (stoneworts)
- macroscopic algae with complex thalli, 400 spp. fossils (gyrogonites) > 380 mya (Devonian)
- central stalk w/ multinucleate cells, whorls of branches
- oogonia (♀ gametangia) and antheridia (♂ gametangia) surrounded by unistratose sheath (in land plants the sheath multistratose
- CaO encrustation (name!)
- freshwater – but often saline, alkaline
What algae may be the closest living relatives to land plants?
Zygnematophyceae (green algae), Charophyceae (stonewarts) and Coleochaete
Which algae do not have motile stages?
Zygnematophyceae (green algae) and most red algae and diatoms
- Zygnematopycea: is the richest charophyte group with more than 5000 species. It occurs unicellular, filamentous and in colonies. They are all non-motile cells including the gametes.
