Table of Contents
What are Lichens?
Lichens are a symbiotic relationship between a fungus and an algae. The fungus provides the structure and the algae provides the food. Lichens can grow in some of the most extreme environments on Earth.
Lichens are Classified Into Three Types
Lichens are classified into three types: crustose, foliose, and fruticose.
Crustose lichens are those that form a hard, crusty surface. They are the most common type of lichen and are found on trees, rocks, and buildings.
Foliose lichens are those that have leaf-like structures. They are the second most common type of lichen and are found on the bark of trees and on rocks.
Fruticose lichens are those that have a shrub-like appearance. They are the least common type of lichen and are found on the bark of trees and on rocks.
Classification Based on Their Habitat:
There are many ways to classify animals, and one way is by their habitat. Animals can be classified as aquatic (living in water), terrestrial (living on land), or aerial (living in the air). Another way to classify animals is by their diet; for example, herbivores, carnivores, and omnivores.
Classification Based on Their Internal Structure:
There are three main types of classification systems, which are based on their internal structure:
1. Cellular Classification: This is the classification system that is based on the cells of an organism. The cells can be classified as prokaryotic or eukaryotic. Prokaryotic cells are the simplest cells and they do not have a nucleus or other membrane-bound organelles. Eukaryotic cells are more complex cells and they have a nucleus and other membrane-bound organelles.
2. Tissue Classification: This is the classification system that is based on the tissues of an organism. The tissues can be classified as epithelial, connective, muscle, or nerve. Epithelial tissues are thin and flat and they line the surfaces of organs. Connective tissues are tough and support the other tissues. Muscle tissues are responsible for movement. Nerve tissues are responsible for transmitting signals throughout the body.
3. Organ System Classification: This is the classification system that is based on the organ systems of an organism. The organ systems can be classified as the digestive system, the respiratory system, the circulatory system, the excretory system, or the reproductive system. The digestive system is responsible for breaking down food and absorbing the nutrients. The respiratory system is responsible for bringing oxygen into the body and removing carbon dioxide. The circulatory system is responsible for transporting the nutrients and oxygen to the tissues and removing the waste products. The excret
Classification Based on their Fungal Partner:
The two main classifications of fungi are ascomycetes and basidiomycetes. These two classifications are based on their fungal partner.
Ascomycetes are fungi that have a partner that is an ascus. An ascus is a sac-like structure in which the spores of the ascomycete are formed.
Basidiomycetes are fungi that have a partner that is a basidium. A basidium is a club-shaped structure in which the spores of the basidiomycete are formed.
Also Read: Important Topic Of Biology-Lichens
Lichen Algae
Lichen algae are a type of algae that form a symbiotic relationship with a fungus. The algae provide the fungus with food and the fungus provides the algae with shelter and protection. Lichen algae can be found in a variety of different environments, including wetland areas, forests, and deserts.
General Characteristics of Lichens
Lichens are composite organisms consisting of a fungal component and an algal component. The fungus is a symbiont of the alga and the two components are physically and functionally integrated. The alga provides the fungus with photosynthates, and the fungus provides the alga with protection from desiccation, pollutants, and predators. Lichens are distributed worldwide and occur in a wide variety of habitats, including soils, rocks, trees, and buildings.
Lichens are slow-growing and long-lived. The thallus (body) of a lichen is typically a few millimeters to a few centimeters in diameter. Lichens are usually either foliose (leafy) or crustose (crusty). Lichens are usually gray, green, or brown, but can be any color. Lichens reproduce asexually by fragmentation or by the production of spores.
