Classification is a dynamic scientific endeavour that seeks to organise creatures based on accumulated knowledge from various domains. It aids in defining the links between organisms and between organisms and their environments.
Five Kingdom Classification System
Historically, all living things were divided into two kingdoms: plants and animals (or so I was taught). Animals were everything that moved, ate, and grew to a certain size before stopping. Plants were any living organism that did not move or eat and grew continuously. Plantae (plants) Animalia (animals) Monera (monera) (the prokaryotes). Many biologists currently divide Monera into Eubacteria and Archaebacteria.
Kingdoms are subdivided into phyla, which in turn are subdivided into classes, orders, families, genera, and species. A species is a type of organism, like a dog, tiger shark, amoeba, or Acer palmatum (Japanese maple).
Larger organisms are easy to classify, but in a microenvironment it might be difficult. If you’ve studied biology, describe an individual living item and try to classify it by kingdom.
The monera (includes Eubacteria and Archaebacteria)
Individuals are single-celled, have a cell wall, lack chloroplasts and other organelles, and lack a nucleus. Monera are typically quite small, although one variety, blue-green bacteria, resembles algae. They are filamentous and relatively long in length, green, and lack obvious structure inside the cells. There is no evident mechanism of feeding. They either take nutrients via the cell wall or synthesise them through photosynthesis.
Protista
Protists are unicellular organisms that typically move via cilia, flagella, or amoeboid processes. Generally, there is no cell wall, however certain species do have one. They contain organelles, including a nucleus, and may contain chloroplasts, which is why some are green and others are not. They are minuscule, however many are large enough to be identified under a dissecting microscope or even a magnifying glass. Nutrients are obtained through photosynthesis, consumption of other species, or a combination of the two.
Fungi
Fungi are multicellular organisms that possess a cell wall, organelles, and a nucleus but lack chloroplasts. They lack movement mechanisms. Fungi come in a variety of sizes, from microscopic to extremely big ( such as mushrooms). Absorption is the process by which nutrients are obtained. Fungi obtain the majority of their nourishment from rotting matter.
Plantae
Plants are multicellular and the majority do not move, while certain plants’ gametes do so via cilia or flagella. The nucleus, chloroplasts, and cell walls are present. Photosynthesis is the process through which nutrients are obtained (they all require sunlight).
Animalia
They have cilia, flagella or contractile protein-based muscular organs. They include organelles and a nucleus, but do not contain chloroplasts or cell walls. Animals obtain nutrition by swallowing.
Importance Of Classification Of Animal Kingdom
Animal kingdom classification is critical for understanding the relationships between all living organisms. Species are classified using the Linnaeus approach based on shared traits.
The Swedish botanist Carolus (Carl) Linnaeus devised this method of animal kingdom classification in the early 1700’s. The Linnaeus Method, also known as Linnaean Taxonomy, establishes a taxonomic hierarchy and binomial nomenclature, which assigns each animal species a two-word scientific name. This approach of naming animals scientifically is often rooted in Latin and involves combining the genus and species. Humans, for example, are categorised as homo sapiens, but wolves are classed as canis lupus.
The more characteristics that a group of animals shares, the more specific that group of animals is. Each species is classified according to nine branching types. The fundamental way of classifying animals is as follows:
- Domain.
- Kingdom.
- Phylum.
- Class.
- Order.
- Suborder.
- Animal Families.
- Genus.
- Species.
Six Classifications Of Kingdoms
Carl Woese and colleagues proposed the fundamental division of prokaryotes into Eubacteria (later renamed Bacteria) and Archaebacteria (later renamed Archaea) in 1977, based on the structure of ribosomal RNA this later resulted in the proposal of three “domains” of life, Bacteria, Archaea, and Eukaryota. When combined with the five-kingdom model, this resulted in a six-kingdom model with Bacteria and Archaea replacing Monera. Although this six-kingdom paradigm is frequently used in recent US high school biology textbooks, it has come under fire for allegedly undermining current scientific agreement. However, the split of prokaryotes into two kingdoms is retained in Thomas Cavalier-latest Smith’s seven kingdoms theory, albeit Protista is replaced with Protozoa and Chromista.
Conclusion
Although recent discoveries in genetic research have proposed new changes and rekindled the debate among experts, the classification of nature’s five kingdoms remains the most widely recognised today. This is the case for Carl Woese and George Fox’s sixth kingdom, which separated bacteria into two groups in 1977 (Archaea and Bacteria), and Cavalier-seventh Smith’s kingdom, which introduced a new group for algae termed Chromista to the previous six.