Tag: lichens ( the nature's pioneers )

Quizzes (0) Questions (111)

Questions Related to lichens ( the nature's pioneers )

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

There exists a close association between the algae and the fungus within a lichen. The fungus

  1. Fixes the atmospheric nitrogen for the alga.

  2. Provides protection, anchorage and absorption for the alga.

  3. Provides food for the alga.

  4. Releases oxygen for the alga.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The photobiont supplies the association of organic carbon from photosynthesis, and the mycobiont ensures protection, and regulates the supply of minerals and water. The nutritional exchange between partners is probably much more complex than exchange of water and minerals for organic carbon.

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

A teacher was explaining about a constant physical contact involving almost equal physiological interdependence in two different thalloid forms. He was trying to explain, which one of the following?

  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

The teacher was explaining the advent of lichen formation. A lichen is made up of a simple photosynthesising organism, usually green algae or cyanobacteria, surrounded by filaments of a fungus. Generally, most of lichens bulk is made of interwoven fungal filaments, although in filamentous and gelatinous lichens this is not the case. The fungus is called as a mycobiont. The photosynthesizing organism is called as a photobiont. Algal photobionts are called as phycobionts. Cyanobacteria photobionts are called as cyanobionts. The part of a lichen that is not involved in reproduction, the "body" or vegetative tissue" of a lichen, is called as the thallus. The thallus form is very different from any form, where the fungus or alga are growing separately. The thallus is made up of filaments of the fungus called as hyphae. The filaments grow by branching then rejoining to create a mesh, which is called being. The mesh of fungal filaments may be dense or loose.

Thus, the correct answer is option D.

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. A parasitic relationship with the alga.

  2. A symbiotic relationship with the alga.

  3. A saprophytic relationship with the alga.

  4. An epiphytic relationship with the alga.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lichen is a stable symbiotic association between a fungus and algae. The combined life form has properties that are very different from the properties of its component organisms. Lichens come in many colors, sizes, and forms. The properties are sometimes plant-like, but lichens are not plants. 

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

Lichens grow at a very slow rate (1 mm per year). In how many years, a lichen matures?

  1. 1 - 4 years

  2. 4 - 8 years

  3. 100 years

  4. 20 - 25 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lichens usually reach maturity and produce ascocarps at 4-8 years of age. The age of some lichens in alpine-arctic area is 1000-4500 years. Their longevity can be partially attributed to their ability to survive long periods of drought unharmed.

Thus, the correct answer is option B.

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

In majority of lichens, there is association of

  1. Green algae and ascomycetes

  2. Green algae and basidiomycetes

  3. Blue green algae and ascomycetes

  4. Blue green algae and basidiomycetes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The lichen fungi (kingdom Fungi-ascomycetes) cultivate partners that manufacture food by photosynthesis. Sometimes, the partners are algae (kingdom Protista), other times cyanobacteria (kingdom Monera), formerly called as blue-green algae.

Thus, the correct answer is option C.

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

Which of the following structure helps in the respiration of lichens _____________.

  1. Soredia

  2. Cyphella

  3. Isoidia

  4. Cephalodia
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The cyphellae are small circular depressions and are found irregularly scattered on the underside of some lichens such as Sticta. They have a definite rim made of spherical thin walled cells and open into the medulla of the lichen. 
So, the correct answer is 'Cyphella'
Multiple choice botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

Soredium is a propagule of __________.

  1. Lichens

  2. Phycomycetes

  3. Zygomycetes

  4. Both axcomycetes and basidiomycetes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Soredia are common reproductive structures of lichens. 
  •  Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or green algae.
  •  These can be either scattered diffusely across the surface of the lichen's thallus, or produced in localized structures called soralia.