The Science Of Classifying Living Things: An In-Depth Look

Since the beginning of human civilization, we have sought to organize the vast diversity of life on our planet. But what is the specific science behind classifying living organisms like animals and plants? This field provides crucial foundations for biology, evolution, and even medicine.

If you’re short on time, here’s a quick answer: The science of classifying living things is called taxonomy or biological systematics.

Definition and History of Taxonomy

Taxonomy is the scientific discipline of classifying and categorizing living organisms based on their shared characteristics. It helps scientists understand the relationships between different species and provides a framework for organizing and studying the vast diversity of life on Earth.

Origins of Modern Taxonomy with Carl Linnaeus

The foundations of modern taxonomy can be traced back to the 18th century Swedish botanist Carl Linnaeus. Linnaeus developed a hierarchical system of classification, known as binomial nomenclature, which assigns every living organism a unique two-part Latin name.

This system is still widely used today and forms the basis of modern taxonomy.

Linnaeus’ work revolutionized the field of biology, as it allowed scientists to communicate more effectively and accurately about different species. By using a standardized naming system, researchers could avoid confusion and easily refer to specific organisms in their studies.

Linnaeus’ contributions to taxonomy earned him the title “Father of Modern Taxonomy.”

Taxonomy vs. Systematics – Precise Meanings

While taxonomy and systematics are closely related fields, they have distinct meanings within the scientific community. Taxonomy refers to the classification and naming of organisms, while systematics focuses on the evolutionary relationships between species.

Taxonomists use a variety of characteristics, such as morphology, genetics, and behavior, to group organisms into hierarchical categories, including kingdoms, phyla, classes, orders, families, genera, and species.

Systematists, on the other hand, analyze these classifications to understand the evolutionary history and relatedness of different species.

It’s important to note that taxonomy and systematics are dynamic fields that are constantly evolving as new discoveries are made and scientific understanding improves. Researchers continue to refine and update classification systems as they gain new insights into the relationships between living organisms.

For more information on taxonomy and its history, you can visit the Encyclopedia Britannica website.

Principles and Concepts of Taxonomy

Taxonomic Ranks: Kingdom, Phylum, Class, etc.

Taxonomy is the science of classifying living organisms into different groups based on their characteristics and evolutionary relationships. One of the fundamental principles of taxonomy is the use of taxonomic ranks, which help organize and categorize organisms into hierarchical groups.

The highest taxonomic rank is the kingdom, which represents the broadest category. Currently, there are five recognized kingdoms: Animalia, Plantae, Fungi, Protista, and Monera. Each kingdom is further divided into smaller groups, such as phylum, class, order, family, genus, and species, in a hierarchical manner.

For example, humans belong to the Animalia kingdom, Chordata phylum, Mammalia class, Primates order, Hominidae family, Homo genus, and Homo sapiens species.

Taxonomic ranks allow scientists to organize and compare different organisms, making it easier to study and understand the diversity of life on Earth. They provide a standardized system for naming and classifying organisms, facilitating communication and research among biologists around the world.

Phylogenetic Relationships and Evolutionary History

Another important concept in taxonomy is understanding the phylogenetic relationships among different organisms. Phylogeny refers to the evolutionary history and relationships between species. By studying the similarities and differences in their genetic material, morphology, and behavior, scientists can reconstruct the evolutionary tree of life.

Phylogenetics is the field of biology that uses molecular data and other evidence to determine the evolutionary relationships between organisms. This information helps in classifying organisms based on their shared ancestry and helps in understanding how different species are related to each other.

Through the use of techniques such as DNA sequencing, scientists can compare the genetic material of different organisms to identify similarities and differences. These similarities and differences provide clues about the evolutionary relationships between species, allowing scientists to construct phylogenetic trees that depict the evolutionary history of life on Earth.

Morphology, Genetics, and Phylogenetics in Classification

Classification in taxonomy is based on multiple criteria, including morphology, genetics, and phylogenetics. Morphology refers to the physical characteristics of organisms, such as their shape, size, and color.

These characteristics are often used to classify organisms into different groups based on their similarities and differences.

Genetics plays a crucial role in taxonomy as well. Advances in DNA sequencing technology have revolutionized the field of taxonomy by allowing scientists to compare the genetic material of different organisms.

DNA sequences provide valuable information about the evolutionary relationships between organisms and help in determining their classification.

Phylogenetics combines the information from morphology and genetics to construct phylogenetic trees that represent the evolutionary relationships between species. These trees help in understanding the evolutionary history of life and provide insights into the relationships between different groups of organisms.

Processes and Methods of Taxonomists

Taxonomists are scientists who specialize in classifying and categorizing living organisms. They play a crucial role in our understanding of the diversity of life on Earth. In order to accurately classify organisms, taxonomists employ various processes and methods that involve collecting, analyzing, and comparing different characteristics of plants and animals.

Plant and Animal Collection and Specimen Preparation

One of the first steps in the taxonomic process is the collection of plant and animal specimens. Taxonomists may travel to different locations, such as forests, oceans, or even remote areas, to gather samples of various organisms.

These specimens are carefully collected and preserved to maintain their original form and structure. Preservation techniques include drying, pressing, or using preservatives to prevent decay.

Once the specimens are collected, taxonomists meticulously prepare them for further analysis. This involves cleaning, removing excess tissues, and mounting the specimens on sheets or in containers. Proper specimen preparation is crucial to ensure accurate identification and comparison of various characteristics.

Analyzing Morphology and Anatomy

Morphology and anatomy are important factors in the classification of organisms. Taxonomists analyze the physical characteristics of organisms, such as shape, size, color, and the arrangement of body parts.

By examining these traits, taxonomists can identify similarities and differences between different species. They may use specialized tools, such as microscopes or imaging techniques, to study the intricate details of an organism’s structure.

Comparative anatomy is another method used by taxonomists to classify organisms. By dissecting and studying the internal structures of different organisms, taxonomists can identify similarities and differences in their anatomical features.

This information helps in determining relationships and grouping organisms into taxonomic categories.

Biochemical Testing and DNA Sequencing

Biochemical testing and DNA sequencing have revolutionized the field of taxonomy. Taxonomists now have access to advanced techniques that allow them to analyze the genetic material of organisms. By studying the DNA sequences, taxonomists can uncover valuable information about the evolutionary relationships between different species.

Biochemical tests, such as protein electrophoresis or enzyme assays, can also provide insights into the biochemical makeup of organisms. These tests help in identifying unique biochemical characteristics that can be used for classification purposes.

Furthermore, DNA sequencing enables taxonomists to compare the genetic makeup of different organisms. This information can be used to determine evolutionary relationships and create phylogenetic trees.

DNA sequencing has opened new avenues for taxonomists, allowing them to more accurately classify organisms based on their genetic similarities and differences.

Major Groups of Living Things

Taxonomy of Animals (Zoology)

One of the major groups of living things is animals, which are classified based on their characteristics and evolutionary relationships. This field of study is known as zoology. Taxonomy, the science of classifying organisms, helps us understand the diversity of animals and their relationships with one another.

The classification system for animals is hierarchical, starting from the broadest category, the kingdom, and moving down to more specific groups. The five main kingdoms of animals are:

  • Animalia (animals)
  • Plantae (plants)
  • Fungi (fungi)
  • Protista (protists)
  • Monera (bacteria and archaea)

Within the kingdom Animalia, animals are further classified into phyla, classes, orders, families, genera, and species. For example, humans belong to the phylum Chordata, class Mammalia, order Primates, family Hominidae, genus Homo, and species Homo sapiens.

Zoologists study the characteristics, behavior, and habitats of different animal groups to better understand their roles in ecosystems and their evolutionary history. Through taxonomy, scientists can uncover the similarities and differences between species, helping us appreciate the incredible diversity of animal life on Earth.

Taxonomy of Plants (Botany)

Plants, like animals, are also classified into various groups based on their characteristics and evolutionary relationships. This branch of science is known as botany. Understanding the taxonomy of plants helps us identify and categorize different species, study their adaptations, and explore their ecological roles.

Similar to the animal kingdom, the plant kingdom is organized into hierarchical levels of classification. The main divisions of plants are:

  • Bryophytes (mosses, liverworts, and hornworts)
  • Pteridophytes (ferns and horsetails)
  • Gymnosperms (conifers and cycads)
  • Angiosperms (flowering plants)

Within each division, plants are further classified into different classes, orders, families, genera, and species. For example, the beautiful rose belongs to the division Magnoliophyta, class Magnoliopsida, order Rosales, family Rosaceae, genus Rosa, and species Rosa × damascena.

Botanists study plant taxonomy to understand the relationships between different plant species, their morphological and physiological adaptations, and their ecological importance. This knowledge is crucial for conservation efforts, agriculture, and even medicinal research.

Microbial Taxonomy (Bacteria, Archaea, and Protists)

Microbes are microscopic organisms that play crucial roles in various ecosystems, including our own bodies. The taxonomy of microbes, which includes bacteria, archaea, and protists, helps scientists classify and understand these diverse organisms.

Bacteria and archaea are prokaryotic organisms, meaning they lack a true nucleus and membrane-bound organelles. Bacteria are classified into various phyla, such as Firmicutes, Proteobacteria, and Actinobacteria.

Archaea, on the other hand, are divided into several phyla, including Euryarchaeota and Crenarchaeota.

Protists, on the other hand, are eukaryotic microorganisms that do not fit into the categories of plants, animals, or fungi. They are classified into various groups, including amoebas, ciliates, and algae.

Microbial taxonomy helps scientists understand the diversity of microbes, their evolutionary relationships, and their ecological roles. It also aids in the identification of pathogenic microorganisms and the development of strategies to control and prevent microbial infections.

For more information on the classification of living things, you can visit the NCBI Taxonomy Browser.

Applications and Importance of Taxonomy

Biodiversity Studies and Conservation

Taxonomy plays a crucial role in biodiversity studies and conservation efforts. By classifying and categorizing different species, taxonomists provide a framework for understanding the diversity of life on Earth.

This knowledge is essential in identifying and monitoring endangered species, as well as developing effective conservation strategies. For example, taxonomists have helped identify and protect endangered species like the Sumatran orangutan and the African elephant, contributing to their preservation and the overall health of their ecosystems.

By studying the relationships between different species, taxonomists can also uncover valuable information about the interconnectedness of ecosystems, helping us better understand the impact of human activities on biodiversity.

Pest Control and Invasive Species Management

Taxonomy is instrumental in pest control and managing invasive species. By accurately identifying and classifying pests and invasive species, scientists can develop targeted control methods that minimize harm to the environment and non-target organisms.

For instance, taxonomists have played a crucial role in identifying and managing invasive species like the Asian longhorn beetle and the zebra mussel. Their knowledge of these species’ life cycles, habits, and ecological interactions has enabled the development of effective control strategies, preventing the spread of these harmful organisms and protecting native ecosystems.

Discoveries of New Species

Taxonomy is also vital for discovering and documenting new species. By studying the characteristics and relationships of organisms, taxonomists can identify unique and previously unknown species. These discoveries not only contribute to our understanding of the natural world but also have practical implications.

For example, the discovery of new plant species with medicinal properties can lead to the development of new drugs and treatments. Taxonomy also helps us recognize the importance of undiscovered species in maintaining ecosystem balance and functioning.

Every year, numerous new species are identified by taxonomists, further expanding our knowledge of the incredible diversity of life on our planet.


Taxonomy and systematics allow us to catalog Earth’s abundance of life forms. While originating in rudimentary efforts by early naturalists, taxonomy is now a sophisticated science utilizing anatomy, biochemistry, and genetics.

The work of taxonomists provides a roadmap to the epic diversity of our planet.

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