Tag: lichens ( the nature's pioneers )

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Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Lichens are the associations of 

  1. Bacteria and fungus

  2. Algae and bacterium

  3. Fungus and algae

  4. Fungus and virus
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lichens are association (mutually beneficial) between fungus and alga. The fungal partner is mycobiont and algal partner is phycobion. The mycobiont is usually an ascomycete and phycobiont is usually green algae Lichens can grow in extremely inhospitable conditions In many ecosystems they are the pioneer species. The role of mycobiont is providing body structure and anchorage and absorption of minerals and water. The role of phycobiont is mainly in providing food through photosynthesis. So, the correct answer is 'Fungus and algae'.

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Lichens are well known combination of an alga and a fungus where fungus has 

  1. An epiphytic relationship with the alga.

  2. A parasitic relationship with the alga.

  3. A symbiotic relationship with the alga.

  4. A saprophytic relationship with the alga.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Symbiosis in lichens is the mutually helpful symbiotic relationship of green algae and/or blue-green algae (cyanobacteria) living among filaments of a fungus. The fungus benefits from the algae or cyanobacteria, because they produce food by photosynthesis. The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment, and provide an anchor to it.

Thus, the correct answer is option C.

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Which statements is wrong about lichens?

  1. Some species are eaten by reindeers

  2. Lichens are indicators of pollutions

  3. They grow rapidly about 2 cm per day

  4. They have algal and fungal partners in their thallus
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lichen is a symbiotic partnership between fungus and alga. It has algal and fungal partners in its thallus. In this, the fungus is a dominant partner. Hence, lichen has majority of characteristics of fungus. It absorbs sulphur dioxide from the atmosphere. Hence, it is widely used as indicator of air pollution. It grows very slowly.  It is eaten by snails, squirrels and some species of monkeys and reindeers during winter. They grow at 1 mm per day.

Thus, the correct answer is 'They grow rapidly about 2 cm per day.'

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

A semi-parasite relationship between the algal and fungal components of a lichen is termed as

  1. Helotism

  2. Predation

  3. Parasitism

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 According to Crombic, the relation between an algae and a fungi is helotism. Which is a kind of master-slave relationship, where the algal partner acts as a slave to the fungal partner, because, algae is an autotroph  however, the fungal partner may hinder the reproduction and nutrition of the algae.

So, the correct answer is 'Helotism'

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Body of lichen consists of two dissimilar organisms. Choose the correct option w.r.t. component which form bulk of the thallus

  1. Autotrophic component

  2. Prepare food for fungi

  3. Form sexual reproductive structure

  4. Provide belongs to ascomycetes or sometimes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lichens are the symbiotic association of algae and fungi. Lichens are autotrophic, they can make their own food with the help of sunlight and provide food to the fungi and in return fungi provide protection to the lichen. Lichens always reproduce asexually. It is the most controversial organism, it possesses the characters of algae and fungi both. It is placed in ascomycetes.

So, the correct answer is " Autotrophic component'.

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

A lichen having much branched system of cylindrical or ribbon-like branches but a small thallus, is called as

  1. Foliose lichen

  2. Fruticose lichen

  3. Crsutaceous lichen

  4. Thallose lichen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fruticose lichen ususally round in cross secetion (terete), and most are branched. They can be like little shrubs growing upward, or they can hang down in long strands. The fruticose lichens have much branched cylindrical, ribbon-like, flattened or sometimes filamentous thalli. 

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Lichens are important in the studies on atmospheric pollution because they

  1. Can cause eutrophication

  2. Efficiently purify the atmosphere
  3. Are very sensitive to pollutants like $SO _2$

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.
  • If air is very badly polluted with sulfur dioxide($SO _2$) there may be no lichens present, just green algae may be found. If the air is clean, shrubby, hairy and leafy lichens become abundant
  • Hence Lichens are important in the studies on atmospheric pollution because they are very sensitive to pollutants like sulfur dioxide. 
  • So, the correct answer is ' Are very sensitive to pollutants like $SO _2$.
Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Select the true statements out of the following.

  1. The lichens are curious because they are composite or dual organism.

  2. The apothecium consists of the fungal component only (e.g. Cladonia), such apothecia are called lecideine type.

  3. Parmelia, Physica, Lecanora etc. have more highly developed apothecia called Lecanorine type in which both fungal and algal components are present.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lichens are a small group of curious plants, they are curious because they are the composite or dual organism. They are the association between fungi and green algae or blue-green bacteria.

Apothecium is round and cup-shaped structure. If the apothecium consists only the fungal component, it is known as lecideine type (e.g., Lecidea, Cladonia, Gyrophora) and if it consists bath algal and fungal components it is known as lecanorine type (e.g., Lecanora, Parmelia).
Therefore, the correct answer is option D.

Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

In lichens, medulla has

  1. Endodermis

  2. Hadrome

  3. Hypodermis

  4. Piliferous layer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mosses are flowerless plants that grows as dense green tufts or mats in damp and shady locations. Lichens on the other hand though, they appear similar to mosses, are not related to these are are a composite organism of algae, cyanobacteria and living in a symbiotic relationship in a fungus. The medulla which is found below the cortex in lichens and is made up of loosely woven layer of fungal filaments. Hadrome refers  to collection of hydroids or vascular tissue that occur in some bryophytes or mosses and help in transporting water and minerals drawn from the soil.

Therefore, the correct answer is option B.