To define kinship, biologists look out for what is similar in species but also for what is dissimilar, in the same way you would examine a boy and his grandfather for instance. Echoing the family tree, biologists sum up the relationships between species in a tree: the tree of life.
In Darwin’s time, species were compared according to their morphology – the presence of fur or scales, the number of legs or, in plants, the position of leaves on a stalk for example.
Using the leap in knowledge made in the field of biology combined with the deciphering of theof different species, it is currently possible to estimate the degree of parenthood between all species by ‘reading’ their and . What is more, the calculating power of computers and high-performance methods of analysis are able to compare simultaneously a great number of , or , between many species – from to humans.
All species living on earth share something very intimate:. The that make up are essential to life since they are themselves involved in making . are frequently used by bioinformaticians to construct phylogenetic trees. There are about 200 other ‘universal’ .
…created by scientists who compared 31 families of universalfrom 191 different species.
/ Eubacteria ( )
Unicellular organisms; their is not kept inside a nucleus.
Archaea / ( )
Unicellular organisms; their is not kept inside a nucleus. Unlike , however, archaea generally live in extreme conditions (high acidity, high temperatures, high pressure, …).
Organisms whose have a nucleus which protects their . It is the case of animals – humans included – plants and fungi.
LUCA – Last Universal Common Ancester
represents the hypothetical last common ancestor of all living organisms. It is expected to have been unicellular and to have lived 3 to 4 million years ago.