Concept Of Species and Taxonomic Hierarchy

Introduction

The concept of species and taxonomic hierarchy helps in describing the organisms in terms of their characteristics. This allows the grouping together of organisms that have plenty of similarities. Taxonomy, in particular, is a Biology branch that facilitates the classification of living things. Developed back in the 18th Century, the branch is relevant today. Species are the basic unit of taxonomy. Let us dive deep into the concept of species and taxonomic hierarchy study material. 

Concept of Species 

The species is the fundamental unit or aspect of the taxonomic hierarchy. In simple terms, it is a group of living organisms with certain similarities. 

Botanists have historically been making several attempts to define a species to ascertain the concept of species and taxonomic hierarchy. As a result, they have come up with the following five concepts:

Nominalistic Species Concept

According to this concept, nature is only responsible for producing individuals and nothing more. 

Typological Species Concept or Taxonomic species concept

According to this concept, the species refers to a group of organisms considered very natural. Therefore, according to this concept, a natural taxon in classification has a generalised invariant pattern that all group members share.

Biological Species Concept

According to it, a species is a group of interbreeding natural populations that has reproductive isolation from such other groups.

Evolutionary Species Concept

According to this concept, species is a spatiotemporal lineage of populations whose evolution takes place separately from other lineages. 

Ecological Species Concept

It states that species are individuals whose maintenance takes place ecologically rather than reproductively. 

Taxonomic Hierarchy

Taxonomy refers to the branch of biology that facilitates the classification of all living things. It was developed by Swedish botanist Carolus Linnaeus back in the 18th Century. Linnaeus came up with the idea of binomial nomenclature. This system involved giving a name to each type of species, genus, and organism. 

Linnaeus also developed the taxonomic hierarchy, a classification system for living organisms. This hierarchical system is very important in species and taxonomic hierarchy study material. Under it, there were eight ranks for classifying organisms. These eight ranks, which are part of the concept of species and taxonomic hierarchy, are as follows:

• Domain
• Kingdom
• Phylum 
• Class
• Order
• Family
• Genus
• Species 

A taxon refers to a group of organisms whose classification takes place as a unit. This classification can be of a specific or general nature. For example, all the monkeys are a taxon at the species level since they belong to the same species. However, we could also say that monkeys are related to other primates at the order level since they belong to the order primates. 

Taxonomic ranks in the Taxonomic Hierarchy

The following is a brief description of the various taxonomic ranks in the taxonomic hierarchy:

Domain

A domain is the highest and the most general rank of living organisms. The three domains of life are as follows:

• Bacteria
• Archaea
• Eukaryota

Kingdom

The kingdom is the highest taxonomic rank. The agreed-upon types of kingdoms are as follows:

• Animalia
• Plantae
• Fungi, Protista
• Archaea
• Bacteria 

Sometimes, the grouping of archaea and bacteria occurs as one kingdom called monera. 

Phylum

Phylum is the rank that comes after Kingdom, and it is more specific. For example, in the concept of species and taxonomic hierarchy, according to experts, there are 35 phyla in the kingdom Animalia alone.

Class

A rank that is even more specific than the Phylum is the Class. According to biologists, 108 different classes have been identified in the kingdom Animalia. The most important classes among them are as follows:

• Mammalia (mammals)
• Aves (birds), 
• Reptilia (reptiles).

Order

Order is more specific and narrowed down rank than Class. There are between 19-26 orders of the class of Mammalia. The exact number differs depending on how the classification of organisms takes place. Some popular orders of Mammalia are as follows:

• Primates
• Carnivora (large carnivores or omnivores)
• Cetaceans (whales, dolphins, and porpoises)
• Carnivora (large carnivores or omnivores)
• Chiroptera (bats)

Family

Family, in turn, is more specific than Order and is the next hierarchical rank. The Order Carnivora has a total of 12 families. Some popular families in the Order Carnivora are as follows:

• Canidae (dogs, wolves, foxes)
• Felidae (cats)
• Mephitidae (skunks)
• Ursidae (bears)

Genus

Genus is even more specific and narrower than family. Under binomial nomenclature, it involves the first part of an organism’s scientific name while the second part is the species name. So, for human beings, their scientific name is Homo sapiens, in which Homo is the genus while sapiens is the species name. 

Species

The most specific major taxonomic rank in the concept of species and taxonomic hierarchy is the species. However, its division can sometimes be subspecies. According to biologists, there are roughly 8.7 million different species on Earth.

Conclusion

The concept of species and taxonomic hierarchy describes the organisms in terms of their characteristics. This way, those organisms that share sufficient similarities are grouped. The fundamental unit of taxonomic hierarchy is the species. There are five different concepts under species – Nominalistic Species Concept, Typological Species Concept or Taxonomic species concept, Biological Species Concept, Evolutionary Species Concept, and Ecological Species Concept. Taxonomy is the branch of biology by which we can classify all living things. The various taxonomic ranks in the taxonomic hierarchy are- Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.