Lineage (evolution)

An evolutionary lineage is a temporal series of populations, organisms, cells, or genes connected by a continuous line of descent from ancestor to descendant.

[4] Members of a species are considered to evolve as a single unit (or lineage) when they repeatedly share the same genes.

Branches on the tree of life may grow together, a phenomenon called reticulation, which occurs due to different biological processes.

Another process, introgression, occurs when hybrids between distinct lineages transfer novel genetic material through subsequent crossing.

Thus, the tree-like representation would be proper as long as introgression and hybrid speciation are rare or limited to closely related tips (of lineages).