A Monumental Scientific Challenge
Just how big is the Tree of LIfe?
There are around 1,750,000 known species on Earth, with countless more awaiting discovery. Most students of biodiversity believe that the real number may be over 10 million. And these are just the species alive today.
The Tree of Life contains all the species that have ever lived — adding extinct species would push the number to over 100 million! The sheer size of the Tree of Life makes reconstructing it one of the most challenging scientific problems ever undertaken.
How much of the Tree of Life has been reconstructed?
Some 100,000 species have been included in formal phylogenetic analyses so far, between 5% and 10% of the known living species, but perhaps only 1% of the real total, and a fraction of a percent of the species that have ever existed.
However, even if not formally analyzed, virtually all known species can now be assigned provisionally a place in the Tree.
This tree contains 3,000 species representing the lineages of some 30,000 flowering plants:
Shown below are 100 trees, each with 3,000 species (see above), to represent a total of 300,000 species:
This is approximately the number of flowering plant species on Earth today. The shaded trees represent the number of species of flowering plants that have been included in phylogenetic analyses to date. So far, approximately 21,000 species, or 7%, have been included.