10 public questions tagged with this topic.
Chlorella, a green alga, commonly forms a symbiotic association with fungi to form lichens.
Ref: NCERT Class 11 Biology Chapter 3: Plant Kingdom Algae - General Characteristics and Chlorophyceae
The organism is a lichen. Its algal partner prepares food, while its fungal partner provides shelter and absorbs water and minerals. Lichens do not grow in polluted areas and therefore indicate air pollution.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Viruses Viroids Prions and Lichens
In lichens, the algal phycobiont prepares food, while the fungal mycobiont provides shelter and absorbs water and mineral nutrients. Lichens do not grow in polluted areas and therefore serve as pollution indicators.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Viruses Viroids Prions and Lichens
The phycobiont is the autotrophic algal partner and prepares food. The mycobiont is the heterotrophic fungal partner; it provides shelter and absorbs mineral nutrients and water for the association.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Viruses Viroids Prions and Lichens
In lichens, the phycobiont is the autotrophic algal component, while the mycobiont is the heterotrophic fungal component.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Deuteromycetes and Economic Importance
The association is a lichen. The algal phycobiont prepares food, while the fungal mycobiont provides shelter and absorbs water and minerals. Because lichens do not grow in polluted areas, they indicate air pollution.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Bacteria - Structure and Economic Importance
The organism is a lichen, a mutually beneficial association between an algal phycobiont and a fungal mycobiont. The alga prepares food, while the fungus provides shelter and absorbs water and minerals. Lichens do not grow in polluted areas and therefore act as pollution indicators.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Bacteria - Structure and Economic Importance
A lichen is a stable symbiotic consortium dominated by a fungus and a photosynthetic partner, usually a green alga or cyanobacterium. The photobiont supplies carbohydrates produced by photosynthesis, while the fungus provides structure, water retention, mineral access, and protection from environmental stress. In cyanobacterial lichens, nitrogen fixation may add another resource. These reciprocal contributions justify the traditional classification as mutualism, although modern research shows that benefit balance varies and additional yeasts or bacteria may participate. Parasitism would require a net cost to one partner, competition reciprocal harm, and commensalism no measurable benefit to one member. Lichens therefore illustrate integrated function arising from unlike organisms. At population level, this mechanism can influence abundance, coexistence, and evolutionary selection. Separating immediate individual effects from longer-term community outcomes gives the selected concept a clearer ecological meaning and avoids relying only on memorized terminology. The relevant evidence concerns process rather than wording alone. Linking the described pattern to energetic returns, fitness consequences, or receiver responses makes the inference biologically coherent and distinguishes it from the competing alternatives.
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 8-13
The NCERT text highlights a very practical ecological application of lichens. They are exceptionally sensitive to toxic air pollutants, particularly sulphur dioxide (SO2) from industrial emissions. Because they lack roots and absorb everything directly from the air, they rapidly die in polluted areas. Thus, they act as highly effective, natural biological 'pollution indicators'—they simply 'do not grow in polluted areas'.
Ref: NCERT Class 11 Biology > Chapter 2: Biological Classification > 2.6 Viruses, Viroids, Prions and Lichens
Lichens represent a brilliantly successful, intimate, mutually beneficial symbiotic association between an alga and a fungus. The NCERT textbook specifies that the autotrophic, photosynthetic algal component is termed the phycobiont (which prepares food). Conversely, the heterotrophic fungal component is formally termed the 'mycobiont'. The fungus provides structural shelter, absorbs vital mineral nutrients, and retains water for its algal partner.
Ref: NCERT Class 11 Biology > Chapter 2: Biological Classification > 2.6 Viruses, Viroids, Prions and Lichens
