Life on Earth began billions of years ago and has continued ever since. As the environment changed, smaller and simpler organisms appeared first, and as the environment changed, simple organisms developed complex functions and evolved into complex organisms to survive in the changing climate environment. Evolution is the term used to describe this process. In his works and writings, Charles Darwin provided a more comprehensive explanation of the phenomenon of the emergence of life and the evolution of life.
Due to two major inferences drawn from the theory of evolution, evolution is linked to classification:
Lower organisms are those that have not changed over time and have been able to survive by maintaining their basic and primitive body structures for long periods of time.
Higher organisms are relatively recent and have evolved complex body functions in order to survive and reproduce, as well as to produce more healthy progenies in order to maintain their race’s survival and survival.
What is Diversity in the Living World?
The world is dominated by a plethora of living organisms that can be found on land, in water, on ice, in deserts, and in other environments. Every living organism is unique in terms of its structure, body functions, genetic make-up, and so on. This is especially true for bacteria. A variety of structural organs or functions are developed by living organisms in response to the environmental conditions in which they are found in different habitats. Evolution has shaped organisms’ ability to adapt to their changing environments. Biodiversity refers to the presence of different types and classes of organisms in a variety of different environments. Warm and humid climates support a greater diversity of organisms, which is referred to as mega-biodiversity.
Humans are descended from apes, according to evolutionary theory. However, they no longer resemble one another in any way. In addition, every individual is unique in their own right. Every individual has a unique skin tone, hair colour, eye colour, and genetic makeup, which is the most important factor to consider. As a result, every individual has a unique set of genetic characteristics.
As a result, in order to improve identification, we have created groups of organisms that are somewhat similar in appearance and share some functional and structural similarities. Classification is the term used to describe this process. There are a variety of factors that influence how organisms are classified. A significant portion of the work is done on the basis of the following criteria:
- Presence of nucleus
- Body design ; that implies the composition of cells or the presence of single or multiple cells is known as cellular design.
- Food production
- The degree to which organisms that carry out photosynthesis are organised in their bodies
- The organisation of one’s body parts, the development of the body, the development of specialised organs for different functions, the development of organ systems are also some factors
Classification System
The classification of organisms is accomplished through the use of two methods. Among the classification systems used are those that divide organisms into plants and animals, and those that use a five-kingdom system that provides a more detailed and organised classification of organisms:
Two – Kingdom Classification
Carolus Linnaeus devised a two-kingdom classification. Plants and animals were the two categories of organisms that he classified.
The following are some of the limitations of the two-kingdom classification:
- Organisms are classified as either plants or animals according to this classification system. Primitive organisms, on the other hand, were neither of these two types of organisms.
- Fungi are a distinct class of organisms with a distinct structure, physiology, and mode of reproduction from other organisms.
- Lower organisms are not divided into either of the groups according to the classification.
- According to this system, the class of decomposers is not clearly defined.
Five – Kingdom Classification
Whittaker divided the organisms into five different classes,
Monera
Protista
Fungi
Plantae
Animalia
Hierarchy of Classification
At different levels of taxonomic classification, Carolus Linnaeus organised the organisms into different taxonomic groups. These taxonomic groups are listed in the following order, in alphabetical order:
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Characteristics of Five Kingdom
Kingdom Monera
- These are unicellular prokaryotes, which means they have only one cell.
- The organisms are devoid of a true nucleus.
- They may or may not have a cell wall, depending on the species.
- In nature, they can be either heterotrophic or autotrophic.
- Bacteria, cyanobacteria, and other microorganisms are examples.
Kingdom Protista
- This category includes organisms that are both unicellular and eukaryotic in nature.
- They can be classified as either autotrophic or heterotrophic in their mode of nutrition.
- They demonstrate the presence of pseudopodia, cilia, or flagella, which are necessary for locomotion.
- For instance, amoeba and paramecium are examples of microorganisms.
Kingdom Fungi
- These are multicellular, eukaryotic organisms, as the name implies.
- A saprophytic mode of nutrition is used by them, which includes chemoheterotrophic extracellular digestion and other processes.
- Chitin is the material that makes up the cell wall of these organisms.
- They have a symbiotic relationship with blue-green algae and thrive as a result.
Kingdom Plantae
- These are multicellular, eukaryotic organisms, as the name implies.
- Cellulose is the primary component of the cell wall of these organisms.
- They are autotrophs, which means that they produce their own food through photosynthesis.
The kingdom Plantae is subdivided into the following subclasses: Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms.
Kingdom Animalia
- Even though these organisms are multicellular and eukaryotic in nature, they do not appear to have cell walls.
- They are heterotrophs, which means that they are organisms that cannot produce their own food.
- The organisms have a wide range of genetic variations.
- They are organised on an organ-system level.
Earthworms, Hydra, and other organisms are examples.
Conclusion
Everywhere on the planet, there is a great deal of variety in living organisms to be found. The warm and humid regions of the earth are home to a wide variety of species, earning them the title of “region of mega biodiversity.” There are 12 countries in the world that contain more than half of the world’s biodiversity. India is one of these countries. Each individual possesses a distinct DNA make-up. Human beings differ in the way we appear and the various characteristics that contribute to our appearance, such as our height, complexion, and so on. Comparing ourselves with a different species, such as a horse or a fish, we would undoubtedly differ significantly in almost all aspects; however, if a horse is compared to a horse, we would only be able to discern a few distinctions between the two.