2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/97708We investigate the evolution of metal deficient stellar structures, presenting H-burning isochrones covering cluster ages from 800 Myr to 7 Gyr. Evolutionary evidences for selection effects in the metallicity distribution of very metal poor H-burning red giants are reported. The evolution of stars during central and shell He burning is further investigated, discussing the occurrence of He burning pulsators as a function of cluster age.11 pages, 8 encapsulated Postscript figures. Accepted for publication on A&A main journalAstrophysicstext