Levels of Selection

Neutrality has provided evolutionary biologists room to develop the theory of natural selection, and to debate over the levels of selection. The idea that natural selection acts at the level of the individual organism emerged from the Synthesis still a dominant view, during that time developments within the biological sciences led to alternative views that have come to constitute its two chief challengers. On the standard Darwinian view, populations of organisms evolved because the individuals in them have differential levels of fitness, pluralism, and realism. The traditional Darwinian view of the levels of selection thus gives rise to another question of multicellular, eukaryotic beasts like man that emerged sometime during the 3.8-4 billion years during which there has been life on Earth. Elisabeth Lloyd [1992; 2001] further distinguished two issues that are sometimes built into the debate over the levels of selection, what she calls the beneficiary and the manifestor of adaptation questions.