The tree of life

“The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth”.

— Charles Darwin

On the Origin of Species, 1859.

The tree of life

“…would it be too bold to imagine that, in the great length of time since the earth began to exist, perhaps millions of years … that all warm-blooded animals have arisen from one living filament (…) and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end? (…) shall we conjecture that one and the same kind of living filament is and has been the cause of all organic life?”

— Erasmus Darwin

 Zoonomy or the laws of organic life, 1794

The process of evolution produces a pattern of relationships among species, biological connections between living beings and generations, which are often depicted by the image of the tree. As a science, Genealogy is the map of these connections, and contributes with History in the study of the origin of life.

The tree of life is a sacred symbol in different cultures. In different ways, it represents the relationship between Heaven and Earth, in which leaves and branches sprout and mature, while the trunk and roots support these movements, symbolizing immortality, fertility and creation. 

“The tree of life should be called the coral of life.”

— Charles Darwin

Notebook B, 1837.

The inspiration for Darwin’s “The Tree of Life” was not exactly a tree, but a coral. The living organism that served as a model for Darwin’s new concept, summed up under the term “tree thought”, is similar to a coral, but was later identified as red algae (Bossea orbignyana).