Taxonomy - LeFonch

What is Taxonomy?

Taxonomy is a method of organizing different organisms depending on how closely related they are to one another.
They are classified under various groups, each one more inclusive than the one below it.
Groups lower down are more specific and contain only a certain type of organism. Large groups are very broad and contain many different organisms.
The broadest group is a domain, whereas the smallest is a species.
The most accepted theory states that there are 2 domains, Bacteria and Archaea.
Eukaryota, the group containing multi-cellular organisms, used to be its own domain, but it is now considered a sub-domain of Archaea.

Asgard-arkean and proteobacteria lived in symbiosis.
In endosymbiosis, the two organisms became inseparable.
The Asgard-arkean was the host cell and proteobacteria was the mitochondrion.
Mitochondria still contain small amounts of D.N.A. but cannot live as an independent organism.

Biological classification organizes organisms based on their shared history.
Based on evolution and shared ancestors, a family tree can be built between species.
Classification helps us organize information on species.
It helps people describe and understand new species.
Provides international conventions and names for different species.
All creatures have a scientific name.
There are lots of rules for naming and organization.

Classification is traditionally based on shared physical characteristics.
Morphology is the physical traits of an organism.
Nowadays we perform genetic analysis on sequences or entire genomes for more accurate information.
Analyses are done on DNA base sequences and protein amino acid sequences.
This has revealed new information which has led to a lot of adjustment of the traditional arrangement of clades.

The giant panda and the red panda look very similar, have similar diets and live in the same region and were initially thought to be closely related.
However the giant panda is actually a type of bears (Ursidae) and the red panda is more closely related to raccoons and skunks (Ailuridae).
Eurasian blue tit was separated from the genus of Parus caeruleus and into the genus Cyanistes caeruleus.

Cladograms are arranged into trees.
They branch from a common ancestor, either extinct or extant.
Cladograms show the relationships between groups of organisms in terms of evolution.
Branching points, called nodes, show specialization events.
Specialization events are when differentiating species evolved. Keep in mind though that these points occur over millions of years, despite appearing as a clear branch-off.

A clade is a group of organisms that share a common ancestor.
For example if A and B branch off from the ancestor C, then A and B are a clade.

The current naming system we use was created by the Swedish scientist Carl von Linné, who lived from 1707 to 1778.
Although we have changed the initial arrangement, we still follow the rules and groundwork Linné laid out.

Animals are written as their genus name and species name.
Both are written in italics, or underlined if written on paper.
For example Homo sapiens (humans) and Homo erectus are the same genus, but different species.
Organisms are usually named after their morphology, area of discovery, properties, or in honor of a person or scientists.