Week 5: Interactions (Lichens)

Question 1

What are Lichens?

Answer 1

A composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship

Question 2

Poikilohydric organisms

Answer 2

Absorb water from their environment straight through their cortex with no vascular tissue

Question 3

Functional Value of Lichens

Answer 3

1. It depends on the ecosystem
2. Retain water
3. Light colours reflects sunlight, lowering solar absorption in summer
4. Air space acts as an insulating layer, preventing temperature fluxes from ground to air.
5. Important food source

Question 4

Nitrophiles

Answer 4

Species that thrive in nutrient enriched areas, eg. agricultural areas, areas of high N emissions from automobile exhaust, power plants or industry

Question 5

Pollution sensitive/tolerant

Answer 5

Based on species response to a wide range of
pollutants

Question 6

Acidophiles

Answer 6

Species that grow on acidic substrates or thrive in areas of high acid deposition (eg. sulfuric acid)

Question 7

Lichens as Public Health Indicators

Answer 7

Lichens can be used as an
index to predict areas in a city where respiratory illnesses will be more prevalent.

Question 8

What are Microlichens?

Answer 8

Crutose (Crusty)

Question 9

What are Macrolichens?

Answer 9

Foliose (Leafy) & Fruiticose (Fruit Tree)

Question 10

Type of Lichen Substrates

Answer 10

1. Trees
2. Rocks
3. Metal
4. Ground

Question 11

What are Apothecia Lichens?

Answer 11

1. Disk or cup-shaped ascomata
2. Spore producing (sexual) reproductive structure found on lichens
3. Spores help improve genetic diversity of lichen populations, but must unite
   with a free-living algae or cyanobacteria to lichenize

Question 12

What are Soralia Lichens?

Answer 12

1. Specialized structures/sites for asexual reproduction
2. Cuff-shaped
3. Hemispherical/Erumpent
4. Excavate

Question 13

What is Cilia?

Answer 13

Hair-like structures that extend from the margin of the lichen thallus.

Question 14

Common Campus Lichen Species

Answer 14

1. Orange-yellow species
2. Grey Species
3. Larger species

Question 15

Orange-yellow Lichen species sensitivity

Answer 15

1. Xanthoria parietina
   (Maritime sunburst lichen) - Nitrophile
2. Xanthomendoza fallax
   (Hooded sunburst lichen)
   Apothecia - Nitrophile
3. Candelaria concolor
   (Candleflame lichen) - Nitrophile indicator species

Question 16

Small grey lichen sensitivity

Answer 16

1. Physcia adscendens
   (Hooded rosette lichen) - Low N requirement, sensitive to Fluorine
2. Physcia millegrana
   (Mealy rosette lichen) - Nitrophile and pollution tolerant indicator species

Question 17

Large Lichen Sensitivity

Answer 17

1. Flavoparmelia caperata
   (Greenshield lichen) - Nitrophile indicator species
2. Parmelia sulcata
   (Hammered Shield lichen) - Nitrophile and pollution tolerant indicator species