Science: Biology
6.2.5 Classification
Exam Board: AQA
Classification
In the 1700s, Carl Linnaeus developed a 7-Level system to classify all living organisms into groups.
Kingdom → Phylum → Class → Order → Family → Genus → Species
Linnaeus originally classified organisms based on their structure and characteristics.
Over time, technological developments have lead to:
-
A better understanding of internal structured due to improvements in microscopes
-
A better understanding of biological processes
This has provided scientists with new evidence on which to base our model of classification and inspired Carl Woese to develop a ‘three-domain system’ with an 8th level.
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species
In this system, organisms now also fall into 1 of 3 domains:
All organisms have a binomial latin name consisting of its Genus + species.
For example:
-
The regular name for our species is human
-
But the binomial name is Homo sapiens
-
Homo is the Genus and sapiens is the species
-
When writing binomial names, the Genus must be a capital and the species lowercase.
Why use latin?
-
Latin is universal - many scientists speak different languages so if everyone agrees to name things in latin (a dead latin that no longer changes) it prevents confusion
Evolutionary Trees
Closer branches = more related
Fossil and DNA evidence is used to establish the relationships between organisms on these trees.
