Lichen Flashcards
(14 cards)
what is lichen ?
Lichen is a “composite” organism in which a particular kind of fungus is intimately associated with a certain type of eukaryotic green or prokaryotic blue-green alga (or cyanobacterium).
what is foliaceous ?
It is a showy lichen that has appearance of widely spread leaves. It is the most common macrolichen.
How lichen associated with algae?
Although lichens appear to be single plantlike organisms, under a microscope the association is seen to consist of millions of cells of algae (called the phycobiont) woven into a matrix formed of the filaments of the fungus (called the mycobiont).
how many percentages of lichen species ?
the total number of species of lichens represents about 20 percent.
What is taxonomic diversity of algae components about?
The taxonomic diversity of the algal component of lichens is much less. Members of only about 40 genera of green algae and 15 genera of cyanobacteria have been identified as lichen photobionts, and just three of these are found in about 90 percent of all lichens (Tschermak-Woess 2000).
How do unicellular green algae serve as a photobiont ?
The unicellular green alga Trebouxia is exceedingly common and probably serves as the photobiont in perhaps 75 percent of all lichens of all known fungi and about 40 percent of all ascomycetes.
where does lichen live ?
They live in a cold region such as in Amazon rainforest, and the desert. They are very sensitive to environmental pollution.
- Corticolas: in trunks and branches
- Terricolas: in the soil of forest
- Saxicola:on rock and wall
what are the growth form/types of Lichen?
- Crustose Growth Form
- Foliose Growth Form
- Fruticose Growth Form
- Squamulose Growth Form 5.(Lichens with a Dual Growth Form)
Describe Growth Form of Lichen ?
- Crustaceans: with appearance of the scale, tightly affixed to the spectrum, they can be continuous or fragmented to the plates or areolas
- Fructicose: the long-branched is raised or hanging that cdan resemble small tree or entangled bushes
- Foliaceous: is a showy lichens that has a appearance of a widely spread leaves. It is the most common macrolichen.
Major classes of secondary metabolites in lichens ?
- Acetyl-polymalonyl palonyl pathway
- Shikimic acid pathway
- Mevalonic acid pathway
What mammals that use Lichen as a food source ?
Larger mammals that sometimes feed upon lichens include the mule deer, whitetail deer, mountain goat, muskox, and moose.
In the Pacific Northwest, northern flying squirrels rely upon species of Bryoria (brown beard lichens) as their primary winter food source (Maser et al. 1985).
how lichen affects vegetable ?
In some situations, lichens exert considerable influence on the composition of vegetation. Some ground-dwelling lichens, such as species of Cladonia (reindeer lichens), produce chemicals that leach into the soil and inhibit the germination of seeds and growth of young plants.
describe symbiotic relationship between alga and fungus ?
The lichen is the result of symbiosis between fungus and alga which its benefit each other. In lichen, fungus will offer alga a support, moisture, and protect it from heat and dehydration. Likewise, alga will produce the food for itself and for fungus through photosynthesis.
How lichen is created?
- The spore of fungus will encounter the alga
- Spores will grow around the alga and alga reproduce
- They form a new organism (thallus of lichen)
