From octopus to olive tree, from alligator to algae. An organism is something that lives. This means that the concept “organism” is very diverse. However, some characteristics are shared amongst all life on earth. At the basis of all organisms is the cell: the building blocks of life. Moreover, all organisms can grow, reproduce and react to their environment. These and other characteristics of life separate living creatures from their non-living surroundings.
From octopus to olive tree, from alligator to algae. An organism is something that lives. This means that the concept “organism” is very diverse. However, some characteristics are shared amongst all life on earth. At the basis of all organisms is the cell: the building blocks of life. Moreover, all organisms can grow, reproduce and react to their environment. These and other characteristics of life separate living creatures from their non-living surroundings.
Tree of life
In order to organize all organisms, scientists came up with the tree of life. This figure shows all organisms that currently inhabit the earth and all known organisms that used to live on earth. The genealogical tree exists of three big domains: Bacteria, Archaea and Eukarya. Unicellular organisms were the first living creatures on earth to evolve, and still form the biggest group. This means that multicellular organisms (plants, macro-algae, fungi, animals and humans) are a small minority: you can find them in a small corner in the Eukarya domain. In Micropia, you can discover the tree of life with your own eyes.
Viruses aren’t alive
Micro-organisms, or microbes, are found everywhere in the tree of life. Microbes with and without a nucleus, unicellular microbes like baker’s yeast , and multicellular microbes like the tardigrade. One group of microbes is excluded however from the tree of life: viruses. A virus is only a package of genetic material coated in protein. Viruses only meet some characteristics of life. This is why most scientists don’t see viruses as living organisms.