An Overview of Classification of Living Things
Right from childhood, we are taught about various living things that exist on a planet, but are you aware that all living organisms are classified into their Kingdom? If yes, then why is it so? Well, all organisms in the world are classified because they have similar characteristics, like their physical features, habitat, and production.
Imagine no classification of all the plants, animals, human beings, fungi, and bacteria. How would we be able to link the evolutionary relationship among them? Thus classification is crucial. Now let's look closely at the classification of living things and see how living things are classified.
What is Classification, and How do we Classify Living Things?
Classification of living things is the process of grouping and categorising organisms based on their similarities and differences. This system of classification is also known as taxonomy.
Classification is based on the characteristics and structure of organisms, and it is hierarchical, meaning that organisms are grouped into increasingly specific categories.
The Linnaean system of classification has eight major levels, starting with the most general and moving to the most specific. There are, in total five kingdoms or orders of living things.
Following are overviews of each taxonomic level in modern biological classification
Classification of Living Things
Kingdom
In Biology, the kingdom is the second highest rank in which the living organisms are divided. Whitaker was the one who proposed the five-kingdom classification. These five kingdoms are as follows:
Kingdom monera
Kingdom protista
Kingdom fungi
Kingdom plantae
Kingdom animalia
5 Different Types of Kingdom
Phylum
The next level of categorisation is the phylum, which is used to classify creatures into larger groups based on shared characteristics. The phylum Chordata includes humans as well though these two species are all different, Phyla are classified in the same way as the Plantae Kingdom.
Sponges are included under the phylum Porifera.
Coelenterata includes, but is not limited to, jellyfish, hydras, and corals.
Flatworms, or Platyhelminthes.
Roundworms (Nematoda).
Class Annelida includes segmented worms.
Arthropoda: Insects and other arthropods.
Molluscs are a class of molluscs that includes bivalves like clams.
Sea urchins, or Echinodermata, are a kind of echinoderm.
The Chordata, or Chordates.
Class
Within the taxonomic hierarchy, the class comes after the phylum but before the order. Class members are more similar to one another than members of other phyla. Although they share the Phylum Chordata, amphibians and reptiles are in separate classes within that phylum. To reproduce, amphibians (mostly frogs, toads, and salamanders) secrete fluids to keep their skin wet and smooth, and they deposit thousands of jellylike eggs in aquatic environments.
In addition to having dry, scaly skin and reproducing by laying tiny clutches of leathery eggs on land, reptiles (snakes, lizards, turtles, and tortoises) belong to the Class Reptilia.
Order
The order is located between the class and family in the taxonomic ladder. An order's groups share more characteristics than the rest of the class. Mammalian characteristics, such as the need for mothers to provide milk to their young, are shared across the orders of whales and reindeer (caribou), even though they are both classified within the Class Mammalia. Cloven-hoofed animals, including reindeer, cows, pigs, antelope, and giraffes, belong to the Order Artiodactyla. The cetaceans (whales, porpoises, and dolphins) make up their order, which is called the Order Cetacea.
Family
The family is at the second-highest taxonomic level, after the order but before the genus. The relationships between individuals of the same taxonomic family are more extensive than those between members of the same order. The Order Carnivora includes a wide variety of animals, including foxes, coyotes, lions, cats, otters, and weasels. Foxes and coyotes, on the other hand, are members of the family Canidae. The family Felidae includes both lions and cats, whereas the family Mustelidae includes otters and weasels.
Genus
Between families and species lies the taxonomic genus (plural: genera). Significant structural similarities and tight relationships exist between the groups of species that make up a genus. Individuals within the same genus are more closely related to one another than they are to those in other genera within the same family. Family Felidae comprises such diverse cats as lions, tigers, ocelots, housecats, bobcats, and lynx. Tigers and lions are Panthera, whereas ocelots and house cats are Felis, and lynxes and bobcats are Lynxes.
Example of Biological Classification of Phantom
Species
The capacity of individuals of different species to marry and have fertile offspring is the most crucial aspect of species categorisation (those that can breed and produce more offspring). Only between members of the same species can offspring develop normally; interbreeding between members of different species is very rare.
Hybrid offspring between species within the same genus have been seen; however, they nearly invariably prove to be infertile. A mule is the offspring of a horse and a donkey, which is a good illustration of this phenomenon. Since mules are infertile, it's unlikely that any offspring would be viable.
Classification of Humans
Since humans have a nucleus and organelles, Humans are classified in Domain Eukarya. Ingestion, multicellularity, and the lack of cell walls establish us as members of the Kingdom Animalia. Since humans have spinal cords, we belong to the Chordata Phylum (our subphylum is Vertebrata because we have a segmented backbone).
Summary
Through this article, we learned the concept of classification, which is the process of arranging various species, such as animals, plants, fungi bacteria, into groups and subgroups to link their evolutionary pattern, recognise and study them easily.
We learned the biological classification, which is taxonomy, has 7 kingdoms viz, kingdom, Phylum, Class, order, family, genus and Species. We closely studied all the species which are included under each category, and finally, we learned about how living things are classified. We hope you enjoyed reading this article.
FAQs on Order of Living Things
1. What is the classification of living things, and why is it important in science?
The classification of living things, also known as taxonomy, is the scientific method of arranging organisms into groups based on their similarities and evolutionary relationships. It is crucial because it helps scientists to:
Identify and name organisms uniformly worldwide.
Understand the evolutionary links between different species.
Organise vast amounts of biological information in a clear and logical way.
Study biodiversity and support conservation efforts effectively.
2. What are the primary levels used in the order of living things?
The modern system of classification uses a hierarchical structure with seven main levels, arranged from the broadest to the most specific. This order is:
Kingdom: The highest level, grouping organisms based on fundamental characteristics (e.g., Animalia, Plantae).
Phylum: A division within a kingdom (e.g., Chordata for animals with a backbone).
Class: A division within a phylum (e.g., Mammalia for mammals).
Order: A division within a class (e.g., Primates).
Family: A division within an order (e.g., Hominidae for great apes and humans).
Genus: A group of very closely related species (e.g., *Homo*).
Species: The most specific level, identifying a single type of organism (e.g., *sapiens* for modern humans).
3. Who developed the modern system for classifying living things?
The foundation of the modern classification system was developed by Carolus Linnaeus, a Swedish botanist, in the 18th century. He introduced the hierarchical system of classification and, most importantly, binomial nomenclature. This is the two-part naming system (e.g., *Homo sapiens*) that gives every species a unique and universally recognised scientific name.
4. Can you provide an example of how a living thing is classified through all the levels?
Certainly. Let's take the example of the domestic cat:
Kingdom: Animalia (It is an animal).
Phylum: Chordata (It has a spinal cord).
Class: Mammalia (It is a mammal that feeds milk to its young).
Order: Carnivora (It primarily eats meat).
Family: Felidae (It is part of the cat family).
Genus: *Felis* (It belongs to the group of small, non-roaring cats).
Species: *catus* (It is a domestic cat).
Therefore, the full scientific name for a domestic cat is *Felis catus*.
5. Why do scientists use a two-part scientific name (binomial nomenclature) instead of common names?
Scientists use the two-part system of binomial nomenclature for several critical reasons:
Universal Understanding: Common names for an organism can vary by language and region. A scientific name is the same worldwide, preventing confusion.
Specificity: It precisely identifies a single species. For example, the common name 'frog' can refer to thousands of different species, but a scientific name points to only one.
Shows Relationships: Organisms in the same genus (the first part of the name) are understood to be closely related. For example, *Panthera leo* (lion) and *Panthera tigris* (tiger) are both in the genus *Panthera*.
6. How is the 'order of living things' in classification different from the levels of biological organisation?
This is a key distinction between two important biological concepts:
The 'order of living things' in classification (taxonomy) is a system for grouping and relating different species to each other based on shared characteristics. It follows the hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species.
The levels of biological organisation describe the structural hierarchy within a single organism, from the smallest component to the whole being. This order is: Organelles → Cells → Tissues → Organs → Organ Systems → Organism.
7. In the order of living things, why are some groups of animals more likely to become extinct than others?
Within the vast order of living things, certain groups are more vulnerable to extinction due to a mix of biological traits and environmental pressures. For example, large animals at the top of the food chain, like tigers and eagles, are often more at risk. This is because they typically:
Have smaller population sizes naturally.
Require large habitats, which are often destroyed or fragmented by human activity.
Have low reproductive rates, meaning their populations cannot recover quickly from threats like poaching or habitat loss.
