makudang-kudang sujana biologi wantah uning ring kekalih pahan: seleksi viabilitas (utawi pamargin idup), sané mamargi nincapang kawéntenan organisme punika prasida setata maurip, miwah seleksi fekunditas (utawi kesuburan utawi reproduksi), sané mamargi mangda nincapang kawéntenan reproduksi, nincapang kahuripan.
Some biologists recognise just two types: viability (or survival) selection, which acts to increase an organism's probability of survival, and fecundity (or fertility or reproductive) selection, which acts to increase the rate of reproduction, given survival.