THE taxonomy is the branch of Biology responsible for describing, identifying and naming living beings according to established criteria.
At seven taxonomic categories are: kingdom, phylum, class, order, family, genus and species.
The term taxonomy has Greek origin and is formed by the junction of taxis, which means to arrange, and nomos, whose meaning is rule.
Therefore, the classification system of living beings is a means of gathering and organizing information on the diversity of individuals to enable the study of species.
Carl von Linné is known as the father of modern taxonomy, as his book natural system, published in 1735, was indispensable for the classification and nomenclature of living beings as we know them today.
taxonomic classification
The 7 main taxonomic categories, also called taxa, of living things in descending order (or hierarchical order) are:
- Kingdom: most comprehensive taxonomic category that includes phyla;
- Phylum: category inferior to the kingdom and that brings together classes;
- Class: category inferior to the phylum and that gathers orders;
- Order: category below class and which brings together families;
- Family: category inferior to the order and that brings together genres;
- Genre: category inferior to the order and that brings together species;
- Species: more specific taxonomic level.
The species is the fundamental unit of classification of living beings, where beings with exclusive characteristics and that can reproduce among themselves, generating offspring that are also fertile in natural environment.
More recently, the classification of living beings into Domains, a taxonomic group broader than the kingdom. The three domains of living beings are: Eukarya, of the eukaryotic organisms, Bacteria and Archaea, these two group the prokaryotic beings.
There are also intermediate taxonomic groups, such as subphylum, subfamily, subgenus and subspecies.
For example, dogs and wolves belong to the same species. However, a more comprehensive classification makes it possible to distinguish the dog as a subspecies of the wolf. Therefore, the scientific name of the wolf is kennel lupus and of the domestic dog is Canis lupus familiaris.
Also read about Classification of living things into kingdoms.
Examples of classification of living things
Check below three examples of beings that belong to the Eukarya domain, that is, they are made up of eukaryotic cells, those that have a nucleus separated from the cellular cytoplasm.
THE Blue Whale It is the biggest animal on the planet. Its scientific name is Balaenoptera musculus and its taxonomic classification is:
| Kingdom | Phylum | Class | Order | Family | Genre | Species |
|---|---|---|---|---|---|---|
| animalia | Chordata | mammalia | cetacea | Balaenopteridae | Balaenoptera | B. muscle |
O mandacaru is a plant native to Brazil and typical of the Caatinga. Its scientific name is Cereus jamacaru and its taxonomic classification is:
| Kingdom | Phylum | Class | Order | Family | Genre | Species |
|---|---|---|---|---|---|---|
| plant | Magnoliophyta | Magnoliopsid | caryophyllales | cactaceae | Cereus | Ç. jamacaru |
O shitake mushroom It is a type of fungus widely used in cooking. Its scientific name is lentinulus edodes and its biological classification is:
| Kingdom | Phylum | Class | Order | Family | Genre | Species |
|---|---|---|---|---|---|---|
| fungi | Basidiomycota | homobasidiomycetes | agaricales | Marasmiaceae | lentinulus | L. edodes |
know more about classification of living beings.
Difference between taxonomy, systematics and phylogeny
As we have seen, the taxonomy acts in the description and classification of living beings into categories.
THE systematic is a branch that, in addition to studying the organization of living beings, considers the evolutionary relationship between species.
THE phylogeny studies the hypotheses related to the evolutionary histories of living beings, from their ancestors to recent beings.
Therefore, systematics is a comprehensive area that studies biological diversity, taking into account the description of species (taxonomy) and evolutionary kinship (phylogeny).
See too: phylogeny
Biological nomenclature of living beings
Carl von Linné also formulated a method for naming living things that became known as binomial system, as it consists of two names.
The language chosen for the nomenclature is Latin, because being a “dead language” it would not change. Also, the writing should be italicized or underlined in order to make it stand out in the text.
The scientific name of a living being consists of two terms: genus and species.
The genus corresponds to the general epithet and its first letter must be written in capital letters. The species follows and corresponds to the specific epithet.
For example, the popular name of the largest feline in the Americas is jaguar, but its scientific name, according to the nomenclature proposed by Linnaeus, is panthera onca, Where panthera is the gender and Jaguar is the species.
See other examples:
| Popular name | Scientific name |
|---|---|
| Human | Homo sapiens |
| Lion | panthera leo |
| Tiger | panthera tigris |
| Corn | zea mays |
| Cauliflower | brassica oleracea |
| English potato | Solanum tuberosum |
THE trinomial nomenclature is used when referring to a subspecies. For example, the domestic cat is considered by some scholars as a subspecies of the wild cat and, therefore, its scientific name is Felis silvestris catus.
History of classification of living beings
The first methods of classifying living beings date back thousands of years. The few known species were divided into plants and animals.
the greek philosopher Aristotle more than 2000 years ago he organized subgroups that differentiated animals in blood and without blood, in addition to distributing existing plants in trees, bushes and herbs.
The invention of the microscope made it possible to discover new beings and more and more species from the 18th century onwards were identified.
the naturalist Carl von Linné created a system that allowed the classification of about 100,000 species according to anatomical and morphological characteristics and published his material in 1735 in the book natural system. However, the organization proposed by Linnaeus did not take into account the evolutionary relationships between species.
the german biologist Ernst Haeckel in 1894 he contributed to the organization of living beings with the creation of another kingdom called Protista to add to the known Plantae and Animalia. In 1936 the American biologist Herbert Copeland he also proposed the inclusion of the Monera kingdom.
Finally, in 1959, the American biologist Robert Whittaker resumed previous studies and defined the five kingdoms of living beings: Plantae, Animalia, Protista, Monera and Fungi.
Technological advances and studies in molecular biology have made the North American microbiologist Carl Woese in 1977 determined that the kingdom Monera should be extinct so that beings would be divided into kingdoms Bacteria and Archaea.
In 1990, Woese even presented the classification of living beings into domains, a taxonomic category superior to the kingdom. Therefore, the three domains of living beings are: Bacteria, Archaea and Eukarya.
Taxonomy exercises
Take advantage of the following questions to test the knowledge acquired while reading this content.
question 1
The descending order of biological classification is:
a) kingdom, domain, class, order, phylum, genus, family and species
b) domain, kingdom, phylum, class, order, family, genus and species
c) order, class, kingdom, domain, genus, family, phylum and species
d) phylum, family, class, order, kingdom, genus, domain and species
Correct alternative: b) domain, kingdom, phylum, class, order, family, genus and species.
question 2
Biological classification is a system that groups living things according to
a) Common features
b) Eating habits
c) Patterns of evolution of the most recent species
d) Number of known species
Correct alternative: a) Common characteristics.
question 3
The maned wolf is the largest canid in South America and an endangered animal. Its scientific name is Chrysocyon brachyurus, therefore, according to the nomenclature rules of the binomial system, the terms Chrysocyon and brachyurus correspond respectively to:
a) family and order epithet of the maned wolf
b) genus and species of the Guará logo
c) kingdom and class of the maned wolf
d) phylum and domain of the maned wolf
Correct alternative: b) genus and species of the logo-guará.
Check out issues with commented resolution at exercises on classification of living beings.
Bibliographic references
AMBIS, J.M; MARTHO, G.R. Biology of organisms, volume 2. 2. ed. São Paulo: Moderna, 2004.
DIAS, D.P. Biology nature and society, volume 2. 1. ed. São Paulo: Editora Brasil, 2016.
MENDONÇA, V. L. Biology: living things, volume 2. 2. ed. São Paulo: Editora AJS, 2013.
