Genes interacting with the environment leads us to the third important concept for biological literacy: the phenotype. Properly understood, the phenotype is not the textbook simplification “what you see,” but the result of the effect of genes plus the environment plus their interaction (That last component is rather of more interest to specialists than the general public). Both genes and environment play a role: East Africa produces a disproportionate number of distance runners partly because of the small and lightweight bodies of its inhabitants, but also because of a culture that values running and regards competitive running as a ticket out of poverty.
Genetic determinism is thus false and should be avoided. Perhaps there is no need to stress that point, given the excesses of Nazism and other genocidal ideologies; “genetic determinism” is deservedly often used as an epithet. Genes and other biological factors produce organisms, but they do not determine them. The soundbite version: we may be 100% genetic, but we’re not 100% determined.
But environmental or cultural determinism is also false and should also be avoided: even highly environmentally-influenced human traits, such as personality, sexual orientation, intelligence, aggression, and the like, still are phenotypes, with genetic as well as environmental components influencing their expression. Yes, the Tarahumara of the canyons of northwest Mexico value running to such a degree that they are famous for their 48-h jogs covering hundreds of miles. But recognizing the cultural forces at work here should not preclude asking the physiological question of whether the Tarahumara are genetically equipped to process energy more efficiently than the rest of us. If we are cultural determinists, we will never think to ask that question.
An understanding of the true meaning of the concept of phenotype would lead us to a better understanding of not only basic biology, but also prickly issues of race, sex, and behavior. Consider the recent election season, in which there were a fair number of women, African-Americans, Asian-Americans, and lesbian, gay, bisexual, and transgender candidates for office. How often did you encounter, explicitly or implicitly, the misguided idea that their genetically-based characteristics either qualified or disqualified them? Such incidents remind us how useful the concept of phenotype actually is. I repeat: we are 100% genetic—but not 100% determined.
Evolution, adaptation, and phenotype. If teachers could do a better job teaching these concepts, Americans would be more biologically literate, which—dare I hope?—might lead to more thoughtful conclusions about what it means to be human.