But are we not taught in classical evolutionary biology that change or adaptation ... How far do we go to define the tree of life — does it start only from the primordial cell or does it go ...

Life on land was just getting started, and was mostly small. Mosses covered much of the ground and the largest plants of the day grew to just 6 centimeters (2.4 inches).

Microbiology and Molecular Biology Reviews 61, 456–502 (1997) Doolittle, W. F. & Bapteste, E. Pattern pluralism and the Tree of Life hypothesis. PNAS 104, 2043–2049 (2007) Embley, T.