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