Introduction
Lichens are a collection of terrestrial organisms that can be found growing in a variety of habitats, including on rocks, gravestones, walls, tree bark, roofs, soil, and other surfaces. They can be found growing on rocks, gravestones, walls, tree bark, roofs, soil and other surfaces. They are composite organisms that require a clean environment with enough oxygen in order to thrive. Due to their ability to grow on practically any surface, including sea level and high alpine elevations, some species of lichens can be found in a wide range of environmental circumstances as well. These species were discovered approximately 400 million years ago, according to fossil records.
Generally speaking, these organisms can be found in a variety of colours, shapes, sizes, and forms. They are further categorised into several sorts based on the physical characteristics that they possess. There have also been instances where these organisms have been found with small branchlets, flat leaf-like structures, a powder-like appearance, and in a variety of other configurations.
Lichens are in a symbiotic connection with green algae and fungus because of the way they obtain their nutrition from them. Many lichens pair with either one photobiont or more than one photobiont and one mycobiont, the number of which varies from species to species.
According to studies, there are over 18,000 recognised species of lichens, and it has also been estimated that lichens cover approximately 4 to 5 percent of the Earth’s surface. Beard lichens, dog lichens, Iceland moss, and oak moss are just a few of the many types of lichens that exist.
Structure
The interior morphology of lichens is nearly identical across all species, according to the study of their anatomy.
Lignin’s outer surface is composed of fungal filaments that are tightly packed together, forming the cortex and shielding the algal cells from the effects of the sun’s ultraviolet rays.
In most cases, a layer of algal cells can be found behind the dense covering of fungal filaments. In order to allow for gaseous exchange between the cells and the surrounding environment, the algal cells do not have a rigid arrangement or are not densely packed. It contributes to the photosynthetic activity that results in the formation of organic food for lichens.
Located beneath the mass of algae cells, the medulla is a tube-like structure. When growing on a suitable substrate, the medulla of crustose and squamulose lichens will attach directly to it.
Importance Of Lichens
- It is widely recognised that lichens have significant economic value and that they are critical to the environment in a variety of ways
- In some cases, lichens are credited with the conversion of rocks into soil, and they contribute to soil formation and improvement as well as plant growth by providing essential nutrients for plant growth in soil
- Lichens also play a significant part in the nitrogen cycle, absorbing nitrogen from the atmosphere and storing it in their tissues
- People all across the world rely on lichens for food, and they are a vital source of nutrition. Iceland moss is a major source of food in specific sections of both the Northern European and American continents, and it is also found in the Arctic
- Petrologists and geologists can investigate and determine the age and other characteristics of rocks and their surfaces based on the size of these lichens, according to the size of the lichens
- These species have been well-known for their different colouring agents and dyes since the dawn of civilization. They are a good source of natural colours, according to the USDA. The lichens that produce the litmus test, pH indicator, and other colours that are used in laboratories are harvested from a variety of species
- Lichens also serve as a biodegradation agent, degrading contaminants such as polyester, lead, copper, radionuclides, and other radioactive elements that pollute the environment
- Aside from the pharmaceutical industry, lichens are widely employed by a variety of cosmetic sectors and are also used as a natural medication to treat a variety of skin problems and rashes, among other things
- Some types of lichens are used in the degradation of pathogens and other environmental reservoirs that are responsible for certain severe infectious diseases in plants, animals and humans
- They are also a valuable source of food for a variety of aquatic creatures, and they are commonly employed as anti-infective agents in the pharmaceutical industry to create antibiotics, anti-mycobacterial agents, antiviral agents, and anti-inflammatory compounds
Symbiosis
For many years, people believed that lichens were all of the same species. Researchers were able to discover that lichens are actually two or more creatures working together in a process known as symbiosis, thanks to the invention of the microscope in the nineteenth century. Ascomycetes and basidiomycetes are the fungi that form the lichens we see on the ground. Fungi are heterotrophs, which means they must consume their food in order to survive. The fungus in lichens, on the other hand, have devised a method of obtaining their own sustenance. They coexist in symbiosis with cyanobacteria or algae, which are capable of producing their own food through the process known as photosynthesis.
Algae and cyanobacteria normally require a wet environment in order to survive, and as a result, they are rarely seen on terrain that is not near water. The fungi, on the other hand, can absorb water vapour to keep their spouse moist while also providing shade from the harmful UV rays. The cyanobacteria, often known as algae, on the other hand, use water and sunshine to produce the carbohydrates that the fungus requires to exist.
Conclusion
They are a keystone species in a number of ecosystems around the world. Many creatures, such as deer, birds, and rats, use them as a food source and a habitat, and they benefit from their presence. Birds use them as nesting materials because they give them. They shield trees and rocks from the effects of extreme weather conditions such as rain, wind, and snow. Lichens have been used for a variety of purposes by both animals and humans over the years. Animals such as elk, deer, birds, and insects rely on them for food, shelter, and building materials. In fact, some insects have altered their appearance to resemble lichens, which make up a significant portion of their natural environment.