CLASS ELEVEN BIOLOGY CHAPTER 2 BIOLOGICAL CLASSIFICATION PART 7

 CLASS ELEVEN BIOLOGY CHAPTER 2 BIOLOGICAL CLASSIFICATION QUESTIONNAIRE FOR TESTS AND REVISION.

PART 7

1.     What are lichens, and what is their ecological significance?

a.      Lichens are symbiotic associations between algae (phycobiont) and fungi (mycobiont). They are important indicators of air quality and pollution levels.

2.     How do lichens demonstrate mutualism?

a.      Lichens demonstrate mutualism by the algae providing food through photosynthesis, while the fungi provide shelter and absorb mineral nutrients and water for both organisms.

3.     Why are lichens used as pollution indicators?

a.      Lichens are sensitive to air pollution and do not grow in polluted areas, making them valuable indicators of environmental health and air quality.

4.     What roles do algae and fungi play in the lichen symbiosis?

a.      Algae provide carbohydrates through photosynthesis, while fungi provide a structure, absorb water and minerals, and protect the algae.

5.     How are lichens adapted to survive in extreme environments?

a.      Lichens have adaptations such as tolerance to desiccation, UV radiation, and extreme temperatures, allowing them to thrive in harsh habitats like arctic tundra and rocky deserts.

6.     What is the structure of lichens, and why are they often mistaken for single organisms?

a.      Lichens have a thallus structure composed of fungal hyphae intertwined with algae cells. They appear as single entities due to their close physical and functional integration.

7.     How do lichens reproduce, and what are their reproductive structures called?

a.      Lichens reproduce sexually and asexually. Sexual reproduction involves fungal spores, while asexual reproduction involves fragmentation or production of specialized reproductive structures called soredia or isidia.

8.     Name some common types of lichens and their habitats.

a.      Common types include crustose (growing tightly attached to substrate), foliose (leaf-like), and fruticose (shrub-like) lichens. They inhabit diverse environments from tree bark to rocky surfaces.

9.     How do lichens contribute to ecosystem processes?

a.      Lichens contribute to soil formation by breaking down rocks, fix nitrogen in some ecosystems, and provide food and shelter for insects and small animals.

10.  What is the nutritional strategy of lichens?

a.      Lichens are autotrophic due to their algae component, which performs photosynthesis, providing energy-rich carbohydrates to both partners.

11.  Explain the role of lichens in early succession and soil stabilization.

a.      Lichens are pioneer organisms in primary succession, colonizing bare rock and soil, and contributing to soil formation and stabilization through their physical and biochemical activities.

12.  How are lichens used in traditional and modern medicine?

a.      Lichens have been used traditionally in medicines for their antibiotic and antimicrobial properties. Modern research explores their potential in treating infections and diseases.

13.  Discuss the economic importance of lichens.

a.      Lichens have economic value as indicators of environmental health, sources of dyes, food for wildlife, and potential sources of bioactive compounds in pharmaceuticals and industry.

14.  Describe the symbiotic relationship between lichens and their environment.

a.      Lichens interact with their environment by absorbing nutrients, gases, and water from the air, making them sensitive indicators of air quality and environmental change.

15.  How do lichens contribute to cultural and artistic practices?

a.      Lichens have cultural significance in indigenous cultures for dyeing textiles and baskets, and they inspire artists and photographers with their intricate forms and colors.