If some of the germ lines that led from the primaeval soup had not been, to a first approximation, immortal then extant organisms would not exist.

Although individually insignificant, ants make up for this in sheer numbers and total biomass; they are among the dominant extant organisms on Earth.

In extant organisms, proteins with central functions in meiosis are similar to key proteins in bacterial transformation.

For this reason, mycologists are unique among those who study extant organisms in using a dual system of nomenclature.

I don't think there is anything to be concerned about unless there were organisms extant before the earth became inhabitable.

All of these biological disciplines can be involved with extinct and extant organisms.

Thus, a host of prefixes have been defined to describe various branches of the phylogenetic tree relative to extant organisms.

A pan-group or total group is the crown group and all organisms more closely related to it than to any other extant organisms.

A school of investigation called Aktuopaläontologie, subsisting largely in Germany, attempts to investigate biostratinomic effects by experimentation and observation on extant organisms.

When Jubal tries to explain religion to him, Smith understands the concept of God only as "one who groks", which includes every extant organism.