Another theoretical calculation exists, where bending moments up to 39 Nm are evaluated during the stem phase [ 22].
Eventually the operative procedure is divided in Goal Oriented Phases (GOP); 1- Incision phase, 2- Prosthesis phase, subdivided in a. femoral phase b. acetabulum phase c. stem phase 3- Closure phase.
Such a late date for the primary radiation of the extant eukaryotes suggests a long stem phase in the evolution of eukaryotes and has major biological implications.
During the stem phase, the emerging eukaryotic cell, probably, evolved the phagocytic capacity and would engulf additional bacteria, typically, resulting in multiple, transient symbioses and transfer of a varying number of the bacterial symbiont's genes to the eukaryotic genome.
Under this scenario, the gene encoding the single subunit RNAP was transferred from a prophage in the endosymbiont genome to the nuclear genome at the pre-LECA, stem phase of eukaryote evolution.
Conceivably, these quintessentially eukaryotic variants of the HEPN domain originated by rapid sequence evolution from either a bacterial or an archaeal HEPN ancestor at the stem phase of eukaryote evolution antedating the LECA.
It seems likely that during the pre-LECA stem phase of eukaryotic evolution, the diversification of the primitive eukaryotes was limited as suggested by the fossil evidence [ 28].
If this is a valid depiction of the evolutionary history of eukaryotes, developing approaches to the study of the pre-LECA stem phase of eukaryotic evolution is a major challenge for evolutionary biologists.
In the taxonomy we categorised the procedure in 5 different Goal Oriented Phases (GOP): 1. the incision phase 2. the femoral phase 3. the acetabulum phase 4. the stem phase 5. the closure pase Each GOP was subdivided in Goal Oriented Actions (GOA) and each GOA is subdivided in Separate Actions (SA) thereby defining all the necessary actions to complete the procedure.
Stand initiation and competition driven stem exclusion phases represent even-aged forest dynamics.
