Lichens are very sensitive to atmospheric pollution because they are not able to draw minerals from polluted air.

Directions: Read the passage and answer the following question.

For professionals who are engaged in naming different kinds of organisms, lichens have always been a very interesting, rather provocative, challenge. The difficulty with lichens is that lichen is not a separate organism in the sense of being one type of individual. It is actually a close partnership between or cohabitation of two different organisms, a fungus and an alga (Algae are very simple plants). The cohabitation is indeed interesting as the partners are quite unlike in the sense that they are profoundly different.
The two types of organisms participating in the partnership are so closely interwoven that they appear as a single organism. The individual appearance of lichen is entirely different from that of either of the partner organisms that make up the structure of the lichen. Lichens are found in many different but recognizable types and each type is different and distinct. A number of these types have been given specific individual names of their own, in spite of the fact that each one of them is already a combination of two or even three different species.
There are about 1,700 known species of lichen in Britain alone. Through out the world about   18,000 distinct species of lichen have been identified and described. The algal partners in lichens, unlike the fungal partners, are photosy nthetic and are hence capable of   living on their own in nature, as independent species in their own right. The fungal partners in British lichens are generally distinguishable and belong to Ascomycetes or Basidiomycetes. However, for survival in nature they need the companionship of the right kind of algal partner. These fungal partners cannot survive on their own, a fact that is not applicable to their algal partners and many other fungi which can survive on their own.
Lichens use their entire surface area to absorb water and minerals from rainwater. They can even absorb water and minerals directly from the atmosphere. This characteristic property makes lichens extremely sensitive to atmospheric pollution and it is almost impossible for lichens to survive in polluted areas. This is the reason why we find very few lichens around industrial areas and big cities.
The capacity to tolerate pollution varies in different species of lichen. This difference in the tolerance levels make lichens very good biological indicators of the levels atmospheric pollution.   .
If you are interested to know the quality of air in your area, just go for a walk around your local churchyard. You will get an idea about air quality in your area. Churchyards are generally undisturbed areas as compared to other busy areas. The stone headstones found in churchyards provide a good substrate for lichens. A close observation of these lichens will provide you with enough indication as to how good is the air quality in your locality.
Uses Over the ages lichens are put to a number of uses. Lichens were extensively used as pigments or dies for clothing before the advent of the present day synthetic dyes. In fact different lichens were used to produce different dye colors and these colors could be mixed in different proportions to produce a wide variety of new colors and shades.
The chemistry of lichens is indeed very interesting. The fact is that lichens produce a large number of acids and many of them are unique in the sense that they are found only in lichens. It would be very interesting to know that the popular litmus dye widely used as an acid/alkaline indicator in laboratories comes from lichens. Yet another important fact about lichens is that some lichen species have antibiotic properties. Some lichen acids are used in antibiotic drugs and are found to be much more effective than penicillin.

Question

Multiple choice

Lichens are very sensitive to atmospheric pollution because they are not able to draw minerals from polluted air.

Directions: Read the passage and answer the following question.

For professionals who are engaged in naming different kinds of organisms, lichens have always been a very interesting, rather provocative, challenge. The difficulty with lichens is that lichen is not a separate organism in the sense of being one type of individual. It is actually a close partnership between or cohabitation of two different organisms, a fungus and an alga (Algae are very simple plants). The cohabitation is indeed interesting as the partners are quite unlike in the sense that they are profoundly different.
The two types of organisms participating in the partnership are so closely interwoven that they appear as a single organism. The individual appearance of lichen is entirely different from that of either of the partner organisms that make up the structure of the lichen. Lichens are found in many different but recognizable types and each type is different and distinct. A number of these types have been given specific individual names of their own, in spite of the fact that each one of them is already a combination of two or even three different species.
There are about 1,700 known species of lichen in Britain alone. Through out the world about   18,000 distinct species of lichen have been identified and described. The algal partners in lichens, unlike the fungal partners, are photosy nthetic and are hence capable of   living on their own in nature, as independent species in their own right. The fungal partners in British lichens are generally distinguishable and belong to Ascomycetes or Basidiomycetes. However, for survival in nature they need the companionship of the right kind of algal partner. These fungal partners cannot survive on their own, a fact that is not applicable to their algal partners and many other fungi which can survive on their own.
Lichens use their entire surface area to absorb water and minerals from rainwater. They can even absorb water and minerals directly from the atmosphere. This characteristic property makes lichens extremely sensitive to atmospheric pollution and it is almost impossible for lichens to survive in polluted areas. This is the reason why we find very few lichens around industrial areas and big cities.
The capacity to tolerate pollution varies in different species of lichen. This difference in the tolerance levels make lichens very good biological indicators of the levels atmospheric pollution.   .
If you are interested to know the quality of air in your area, just go for a walk around your local churchyard. You will get an idea about air quality in your area. Churchyards are generally undisturbed areas as compared to other busy areas. The stone headstones found in churchyards provide a good substrate for lichens. A close observation of these lichens will provide you with enough indication as to how good is the air quality in your locality.
Uses Over the ages lichens are put to a number of uses. Lichens were extensively used as pigments or dies for clothing before the advent of the present day synthetic dyes. In fact different lichens were used to produce different dye colors and these colors could be mixed in different proportions to produce a wide variety of new colors and shades.
The chemistry of lichens is indeed very interesting. The fact is that lichens produce a large number of acids and many of them are unique in the sense that they are found only in lichens. It would be very interesting to know that the popular litmus dye widely used as an acid/alkaline indicator in laboratories comes from lichens. Yet another important fact about lichens is that some lichen species have antibiotic properties. Some lichen acids are used in antibiotic drugs and are found to be much more effective than penicillin.

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