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Questions and Answers
Which dye is obtained from the brown lichen Parmelia omphalodes?
Which dye is obtained from the brown lichen Parmelia omphalodes?
Which lichen is known to produce an acid-base indicator dye?
Which lichen is known to produce an acid-base indicator dye?
Which lichen is recognized for its ability to whiten hair of wigs?
Which lichen is recognized for its ability to whiten hair of wigs?
What are the three distinct parts found in the cup-like region of a mature apothecium?
What are the three distinct parts found in the cup-like region of a mature apothecium?
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What type of spores are formed as a result of sexual reproduction in Basidiolichen?
What type of spores are formed as a result of sexual reproduction in Basidiolichen?
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What type of damage do crustose lichens primarily cause?
What type of damage do crustose lichens primarily cause?
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Which of the following statements about asci is true?
Which of the following statements about asci is true?
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How do lichens contribute to the formation of soil on rocks?
How do lichens contribute to the formation of soil on rocks?
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Which lichen is highly poisonous due to the presence of vulpinic acid?
Which lichen is highly poisonous due to the presence of vulpinic acid?
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In which part of the lichens do the algal partners reside?
In which part of the lichens do the algal partners reside?
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What is a pioneer activity of lichens in ecological succession?
What is a pioneer activity of lichens in ecological succession?
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What is the economic importance of lichens primarily attributed to?
What is the economic importance of lichens primarily attributed to?
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Which lichen is an early colonizer in the process of plant succession?
Which lichen is an early colonizer in the process of plant succession?
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Which type of lichen fruit body is characterized by the absence of a true hymenium?
Which type of lichen fruit body is characterized by the absence of a true hymenium?
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What is one of the nutrients that lichens provide to animals that consume them?
What is one of the nutrients that lichens provide to animals that consume them?
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Where does the new hypha develop after germination of ascospores?
Where does the new hypha develop after germination of ascospores?
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What are rhizines and what is their primary function in lichens?
What are rhizines and what is their primary function in lichens?
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Which part of Usnea's internal structure is composed mainly of algal cells and fungal mycelium?
Which part of Usnea's internal structure is composed mainly of algal cells and fungal mycelium?
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Breathing pores in some foliose lichens facilitate which of the following processes?
Breathing pores in some foliose lichens facilitate which of the following processes?
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What is the function of cyphellae in foliose lichens?
What is the function of cyphellae in foliose lichens?
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What is the primary way vegetative reproduction occurs in lichens?
What is the primary way vegetative reproduction occurs in lichens?
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What are soredia and what role do they play in lichen reproduction?
What are soredia and what role do they play in lichen reproduction?
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Which structure is characterized as stalked and coral-like, used in asexual reproduction?
Which structure is characterized as stalked and coral-like, used in asexual reproduction?
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Which species of lichen is commonly used in the preparation of bread in Egypt?
Which species of lichen is commonly used in the preparation of bread in Egypt?
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What distinguishes pseudocyphellae from cyphellae in lichens?
What distinguishes pseudocyphellae from cyphellae in lichens?
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Which lichen is specifically noted for its use as fodder for reindeer and muskox in the tundra region?
Which lichen is specifically noted for its use as fodder for reindeer and muskox in the tundra region?
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What medicinal use is attributed to the lichen species Parmelia sexatilis?
What medicinal use is attributed to the lichen species Parmelia sexatilis?
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What is the primary role of the polysaccharide lichenin found in lichens?
What is the primary role of the polysaccharide lichenin found in lichens?
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Which lichen is used in the tanning of leather?
Which lichen is used in the tanning of leather?
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In which context has usnic acid been utilized?
In which context has usnic acid been utilized?
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Which lichen is noted for its use in the treatment of jaundice?
Which lichen is noted for its use in the treatment of jaundice?
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Which lichen is associated with the production of alcohol in brewery and distillation processes in Russia and Sweden?
Which lichen is associated with the production of alcohol in brewery and distillation processes in Russia and Sweden?
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In which type of environment do lichens grow best?
In which type of environment do lichens grow best?
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What are the primary components that make up the composite plant body of a lichen?
What are the primary components that make up the composite plant body of a lichen?
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Which of the following lichen types grows mainly on the bark of trees?
Which of the following lichen types grows mainly on the bark of trees?
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What is a characteristic of saxicoles?
What is a characteristic of saxicoles?
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Which group of algal members is NOT typically associated with lichens?
Which group of algal members is NOT typically associated with lichens?
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What does the view of helotism suggest about the relationship between algal and fungal partners in lichen?
What does the view of helotism suggest about the relationship between algal and fungal partners in lichen?
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Which fungal group is most commonly associated with lichens?
Which fungal group is most commonly associated with lichens?
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Which view suggests that the fungus in lichen is parasitic on the algal component?
Which view suggests that the fungus in lichen is parasitic on the algal component?
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What is the primary distinction between Gynocarpeae and Pyrenocarpeae in Ascolichens?
What is the primary distinction between Gynocarpeae and Pyrenocarpeae in Ascolichens?
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Which type of lichen is characterized by a powdery appearance due to the fungal mycelium partially enveloping algal cells?
Which type of lichen is characterized by a powdery appearance due to the fungal mycelium partially enveloping algal cells?
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Which classification was introduced by Hawksworth and Hill in 1984?
Which classification was introduced by Hawksworth and Hill in 1984?
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What is a defining characteristic of crustose lichens?
What is a defining characteristic of crustose lichens?
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Which fungal group does Basidiolichen belong to?
Which fungal group does Basidiolichen belong to?
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What type of attachment do foliose lichens have to their substratum?
What type of attachment do foliose lichens have to their substratum?
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Which of the following is an example of a Deuterolichen?
Which of the following is an example of a Deuterolichen?
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In general, how are lichens classified based on the structure of their fruit bodies?
In general, how are lichens classified based on the structure of their fruit bodies?
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Study Notes
Lichen Characteristics and Classification
- Lichens are composite organisms, a symbiotic association of algae (phycobiont) and fungi (mycobiont).
- The fungal partner dominates the thallus and produces its own reproductive structures.
- The algal partner carries out photosynthesis, providing carbohydrates utilized by both partners.
- Lichens are thalloid, and are categorized based on morphology into crustose, foliose, and fruticose types.
- Reproduction occurs vegetatively (fragmentation, soredia, isidia), asexually (oidia), and sexually (ascospores or basidiospores, only fungal component involved).
- Ascospores are produced within ascolichens.
- The growth is slow, and they can survive harsh conditions.
Lichen Habit and Habitat
- There are about 15,000 species and 400 genera found globally.
- Lichens commonly grow on bark, rocks, bare soil, etc., in various habitats, with abundant moisture or less pollution.
- Some species thrive in extremely cold conditions (e.g., Arctic tundras, Antarctic regions), while others thrive in highly polluted areas.
Associated Members
- Algal members belong to Chlorophyceae (e.g., Trebouxia, Trentepohlia, Coccomyxa), Xanthophyceae (e.g., Heterococcus) and Cyanobacteria (e.g., Nostoc, Scytonema).
- Fungal members mainly belong to Ascomycotina (e.g., Discomycetes) and a few to Basidiomycotina (e.g., Thelephoraceae).
Nature of Association in Lichens
- Some view lichen relationship as parasitic, with the fungus depending on the alga in some species.
- Others view the association as symbiotic where both partners benefit.
- Another view suggests a dominant-subordinate relationship (helotism), with the fungus as the dominant partner.
Lichen Classification
- Lichens are categorised based on the nature and structure of the fungal fruit bodies.
- They are classified into Ascolichens (belonging to Ascomycotina) and Basidiolichens (belonging to Basidiomycotina). further subdivided into categories like Gynocarpeae (apothecial type) and Pyrenocarpeae (perithecial type), depending on fruit body type.
Thallus Structure
- Thalli are generally grey or greyish green, or in some cases, red, yellow, orange, brown.
- Thallus categorization is done into Leprose, Crustose, Foliose, Fruticose, and Filamentous based on structure.
Specialized Thallus Structures
- Breathing pores for gas exchange
- Cyphellae - cup-like depressions
- Cephalodia - warty outgrowths
Lichen Reproduction
- Lichen reproduction is vegetative (fragmentation, isidia, soredia), asexual (oidia), and sexual.
- Soredia: Dust-like structures made of algal cells and hyphae that propagate the lichen.
- Isidia: Small, stalk-like or lobed structures that spread the lichen.
- Fragmentation: Pieces of the thallus grow into new plants. Sexual reproduction (Ascolichen and Basidiolichen) involves specialized organs:
- Spermagonoum.
- Carpogonium.
- Ascospores, or basidiospores, are produced during sexual reproduction in particular types of lichens.
Lichen Importance
- Economic Importance: As food and fodder (e.g., reindeer moss), medicine (e.g., some species containing antibiotics and other substances), and in some industries (e.g., dyes, cosmetics).
- Ecological Importance: As pioneer colonizers, they help to break down rock, and provide habitat for other organisms. Also, they are sensitive to air pollution, making them good indicators of air quality.
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Description
Dive into the fascinating world of lichens with this quiz that covers their characteristics, classification, and habitats. Learn about the symbiotic relationship between fungi and algae, various morphological types, and the survival strategies of lichens across different environments.
