Tag: lichens ( the nature's pioneers )

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

During unfavourable conditions slime molds form spores which are survival for a long time, spore dispersal take place by

  1. Water currents

  2. Air currents

  3. Insects

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Slime moulds are Saprophytic Protists.
  • They move along decaying twigs and leaves engulfing organic material. 
  • Under a suitable condition, they form aggregation called Plasmodium.
  • During unfavourable condition, the plasmodium differentiates and form fruiting bodies bearing spores at their tips.
  • The spores possess true walls.
  • They are extremely resistant and survive for many years even under adverse conditions. 
  • The spores are dispersed by air currents.
  • So, the correct answer is 'Air currents'.
Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

A teacher explaining physical contact leading to equal physiological dependence between two thalloid forms was telling about

  1. Mycorrhizal association

  2. Establishment of heterothallism

  3. Operation of heterothallism

  4. Advent of lichen formation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lichens are formed by the physical association between fungal partner and the algal partner. The fungal partner acts as a mycobiont and algal partner acts as a phycobiont. In lichens, fungus grow around algae and provide bulk for their growth. The algae and fungus association is must for lichens to reproduce. So, they are physically dependent on each other. Here, both fungus and algae are in their thalloid forms.

So, option D is the correct answer.

Multiple choice botany living world lichen lichens lichens ( the nature's pioneers )

Which of the following are functions of phycobiont in a lichen?

  1. Synthesis of organic food

  2. Nitrogen fixation

  3. Mineral absorbtion

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

a) The phycobiont part of lichen is the autotrophic part which constitutes algae. The function of autotrophic algae is to provide nutrition. It synthesizes organic food by the process of photosynthesis.
b) If the algal component is blue-green algae, then apart from photosynthesis phycobionts also carry out nitrogen fixation. Nostoc, blue-green algae consist of heterocysts that have the enzyme nitrogenase. Nitrogenase converts atmospheric nitrogen into a usable form of nitrogen.

c) Mineral absorption is done by fungal mycelium.
So the correct answer is ' Synthesis of organic food and NItrogen fixation'.

Multiple choice botany living world lichen lichens lichens ( the nature's pioneers )

The component of a lichen may belong to which of the following kingdom/s?

  1. Plantae

  2. Monera

  3. Fungi

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The components of lichen include fungi and algae.
  • Algae may be cyanobacteria or green algae.
  • Cyanobacteria belong to the kingdom monera as they are prokaryotic organisms.
  • Green algae belong to Thallophyta of kingdom Plantae.
  • Fungi belong to kingdom fungi.
  • So the correct answer is " Any of the above".
Multiple choice botany living world lichen lichens lichens ( the nature's pioneers )

Lichens are best indicators of

  1. Water pollution

  2. Soil pollution

  3. Air pollution

  4. Noise pollution
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lichens are used as the indicators of air pollution. These structures grow on tree bark and rocks. Air pollutants which are in the gaseous forms get dissolved in the rainwater, especially SO$ _2$ (sulphur dioxide) can damage lichens, and check them from growing. In places where lichens are not growing, it indicates that the air is heavily polluted with sulphur dioxide and other pollutants. 

Thus, the correct answer is option D. 

Multiple choice botany living world lichen lichens lichens ( the nature's pioneers )

Function of fungal part of a lichen is

  1. Absorption of minerals

  2. Providing food for lichen

  3. Protection

  4. Both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The function of fungal part of a lichen is the absorption of water and minerals from the substratum and providing protection for the phycobiont.
  • Food production is done by phycobiont.
  • So, the correct answer is 'Absorption of minerals and Protection'.
Multiple choice botany living world lichen lichens lichens ( the nature's pioneers )

Which of the following statement holds good with the term lichen?

  1. Lichens are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations

  2. They are multi cellular eukaryotic organisms that are heterotrophs

  3. A composite organism made up of a fungus, that grows symbiotically with an algae or a cyanobacterium

  4. Lichens contains only unicellular organisms with a prokaryotic cell organization
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Mosses are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations.
  • Lichens are multicellular, eukaryotic but they have symbiosis as their mode of nutrition where algal component provides nutrition and fungal component helps in mineral absorption and protection.
  • Lichens contain unicellular cyanobacteria if the algal component contains cyanobacteria but all cells are not unicellular as fungal myceliae are multicellular.
  • So the correct answer is 'A composite organism made up of a fungus, that grows symbiotically with an algae or a cyanobacterium.'
Multiple choice botany living world lichen lichens lichens ( the nature's pioneers )

Which of the following pairs include photosynthetic and saprophytic organisms respectively?

  1. Monocot and dicot

  2. Algae and fungi

  3. Mosses and ferns

  4. Ferns and gymnosperms

  5. Gymnosperms and angiosperms
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Algae are photosynthetic organisms, while fungi are saprophytic organisms.