Classification: phylogeny and taxonomy
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Explainer Video
Summary
Classification: phylogeny and taxonomy
In a nutshell
It is very important to be able to classify organisms correctly. Taxonomy is the science of classification. It involves naming, defining and grouping organisms. Phylogeny is the study of evolutionary history that illustrates the relationship between these organisms. A phylogenetic tree is a diagram that accurately depicts relations between different organisms and species.
Phylogeny
Definition
Phylogeny is the study of the evolutionary history of organisms. Phylogeny allows us to visualise the relations between different species and determine how closely related they are. All species have evolved from common ancestors, which can be illustrated through a phylogenetic tree.
Phylogenetic tree
A phylogenetic tree is used to demonstrate the evolutionary relationships between biological species. All organisms on Earth are part of a vast phylogenetic tree because they share a common ancestry. Each branch in the phylogenetic tree indicates the divergence of a species and the pattern of this branching shows the series of common ancestors.
Taxonomy
Taxonomy is the classification of living and extinct organisms. It consists of naming and organising species into groups based on evolutionary relationships using phylogeny. This allows scientists to identify and study them more easily.
Taxonomic classification
Taxonomic classification consists of eight categories. An organism can only belong to one group per taxon. The further down the table, the more closely related the species are.
TAXON | Description | Example (Homo sapiens) |
| Domain (1.) | This is the largest group and consists of Bacteria, Eukarya and Archaea. | Eukarya |
| Kingdom (2.) | This is the second largest group. The five kingdoms are Animalia, Prokaryota, Protista, Fungi and Plantae. | Animalia |
| Phylum (3.) | The third stage of classification. | Chordata |
| Class (4.) | The fourth stage of classification. | Mammalia |
| Order (5.) | The fifth stage of classification. | Primates |
| Family (6.) | The sixth stage of classification. | Hominidae |
| Genus (7.) | The seventh stage of classification that makes up the first part of a binomial name. | Homo |
| Species (8.) | The smallest group of individual organisms with a similar genotype. They can interbreed to produce fertile offspring. | sapiens |
Binomial naming
The binomial naming system is the nomenclature used to classify organisms. As the name suggests, this contains two taxa, the genus and the species. This eliminates the confusion of using common names and aids in identifying the exact species of an organism. The binomial name is the same across the globe which makes it easier for scientists to collaborate.
Note: Binomial names should be italicised or underlined. If the rest of the text is italic, the binomial name can be in regular font.
Example
Homo sapiens is the binomial nomenclature for humans.
Courtship behaviour
Definition
Courtship behaviour are actions carried out by organisms to attract a mate of the same species. It can be used to aid in classifying animals as it is species specific. Only members of the same species will carry out and respond to courtship behaviours.
Example
Before mating, male fruit flies perform a dance that involves tapping the female, vibrating their wings and licking the female.
FAQs - Frequently Asked Questions
What is courtship behaviour?
Courtship behaviour are actions carries out by organisms to attract a mate of the same species.
What is phylogeny?
Phylogeny is the study of evolutionary history.
What is taxonomy?
Taxonomy is the classification of living and extinct organisms.