NUCLEOTYPIC EFFECT IN HOMEOTHERMS - BODY-MASS INDEPENDENT RESTING METABOLIC-RATE OF PASSERINE BIRDS IS RELATED TO GENOME SIZE

The resting metabolic rate of passerines is shown to be negatively cor related with genome size when body mass is held constant (r = -0.75, P < 0.01). This finding extends previous conclusion for mammals to this bird order. The result holds when higher taxonomic levels are used in stead of the species (for genera, r = -0.76, P < 0.03; for families, r = -0.991, P < 0.01) as well as when the independent contrasts derived from the resolved phylogeny are used instead of the taxa (r = -0.73, P < 0.02), with the evolutionarily older contrasts being more strongly correlated (for the contrasts older than 30 million yr, r = -0.998, P < 0.002). The concept of evolutionary characters consolidation (ECC), previously formulated for mammals, is tested with special reference t o the error fraction in the total character variance. In this test, th e ECC for the nucleotypic effect cannot be proven for mammals as a who le class, but it holds for the two separate orders tested, rodents and passerine birds. An upper taxonomic limit for the ECC is suggested.