Organisms are grouped into categories. We can group them into different categories by their external features, internal anatomy, chromosomes or molecules.
An example of this is the Genus Cains
Golden retrievers Chiwawas Wolfs
These animals are all apart of the genus Cains, due to their genetic make up and physical features.
So how do we represent all these groups and information?
We create diagrams called a phylogeny tree.
Observe the image to the right. As the diagram branches out it becomes more specific, eventually getting to species.
Once we have divided the organisms into their groups, we have to name the groups. This is called taxonomy.
The basic hierarchy of biological classification is shown to the left.
Domains are the most general categories, containing the most diverse organisms.
Species are the most specific categories, containing only a few organisms.
After species we have sub species. Some species will show variation between populations.
Tigers are broken up into 8 sub species. The Bengal Tiger, Indochinese Tiger and Malayan Tiger are only some of the sub species of Tigers.
As you will notice by the pictures, Sub-species are extremely similar.
Scroll over the sub species of tigers to see an image of them
Different organisms within a species will interbreed. However Organisms of different species will often not interbreed in nature.
In some cases different species will interbreed. This often results in a Hybrid which is sterile.
The most common example is a Mule (male donkey + female horse) and Hinny (female donkey + male horse).
Another hybrid is a Liger (shown to the left). This is a cross between a male lion and a female tiger.
We can break all organisms up into three categories. Scroll over the Domains.
We can break up kingdoms into 5 categories. Scroll over the kingdoms bellow
However, some biologist believe there are 6 kingdoms. We can further break down Monera into kingdoms Bacteria and Archea.
