Lichens

Question 1

What makes up a lichen

Answer 1

Ascomycete, basidiomycete yeast, and a photosynthesis partner (algae or Cyanobacteria)

2 microbionts and 1 photobiont

Question 2

Can fungi and algae within lichens grow independently?

Answer 2

Yes

Microbiont cells often grow slowly, don’t reproduce, lack morphology of lichen thallus.
Photobiont cells multiply and reproduce easily in pure culture

Question 3

Taxonomy of lichen is based on ____ morphology

Answer 3

Mycrobiont

Question 4

Who proposed that the algae and fungus grow Independently within a lichen

Answer 4

Beatrix potter

Question 5

Benefits of the lichen symbiont relationship

Answer 5

-lichens able to expand habitat into rocks and trees where there is more solar radiation
-mycobiont may absorb minerals from substrate and may absorb nutrients from the atmosphere (N2) from the algae
-protections for algae within the fungal strucure-chemical, solar and physical protection

Question 6

Upper cortex of lichens can screen ____% of solar radiation

Answer 6

50

Question 7

3 forms of lichens

Answer 7

Crutose
Foliose
Fruiticose

Question 8

Crutose lichen

Answer 8

Form cheats that grow so closely to substrate that they can not be removed without damage to substrate

Question 9

Foliose lichen

Answer 9

Leaf-like, composed of lobes, loosely attached to substrate by rhizines

Question 10

Fruticose lichen

Answer 10

3D in structure, branched and round in cross section

Question 11

Lichens as bio indicators

Answer 11

Are extremely vulnerable to habitat alteration. More lichens=less disturbances

Question 12

Macrobiotic crusts

Answer 12

Intimate association between lichens, mosses and Cyanobacteria.

Stabilize soil against erosion by wind and water

Free-living Cyanobacteria and the Cyanobacteria in lichens, fix nitrogen allowing for nitrogen into habitats

Question 13

Lichens as colonizers

Answer 13

Primary succession

Nicknamed nature’s pioneers because they have the ability to colonize bare rock and are often the first plant-like forms to become established on newly exposed surfaces

Brings in Nitrogen, carbon, invertebrates, traps seeds

Question 14

Boreal lichen woodlands

Answer 14

Boreal forest covers a large part of the northern hemisphere.
Lichen ground cover is 50-90%

Preserve soil moisture, reflect heat, add organic matter, trap seeds

Question 15

Lichens and Caribou

Answer 15

-lichens on ground are primary winter food for caribou (90%)
-rumen microorganisms help metabolize usnic acid in lichens
-partially digested lichens in gut where eat by indigenous people

Question 16

Most serious threat to the continued health of lichens is …….

Answer 16

Increased air pollution

Lichens absorb minerals in rain, and the presence of pollutants, including sulphur, will result in the decline of the thallus.

Species of lichens vary in sensitivity to air pollution-> bio indicator species of pollution intensity (Chernobyl)

Question 17

Lichen dyes

Answer 17

Lichens are a common source of natural dyes. They are extracted by either boiling water or “ammonia fermentation”

Ammonia fermentation involves letting the lichen steep in ammonia for at least 2-3 weeks

Question 18

Lichens for medicine

Answer 18

Estimated that 50% of all lichen species have antibiotic properties. One of the most potent lichen antibiotics is usnic acid as a result the species is commonly used in traditional medicine