Letter to the editor: Darwin’s theory central to biology, immune to bias
This letter is in response to Emily Hoyler’s “Ways of Seeing” piece titled “Darwinism losing its significance” of the Feb. 4 edition of the Addison Independent. Although the article brings up some important and thought-provoking points, there were some misleading and inaccurate statements that I feel obliged to correct as a professional biologist. The main point that I want to make is that Charles Darwin’s theories of natural selection and biological evolution remain the foundation of the entire field of biology. Darwinian theory explains topics as diverse as: the patterning of species distributions across the globe in response to climate change, why invasive species are able to take over new areas, why the human brain is structured and functions as it does, and why bacteria have become resistant to antibiotics (to name a few examples).
Hoyler recommends contextualizing Darwin’s theories historically, and it is a very good point that every scientist has biases associated with their culture. However, the scientific method is based upon repeated testing of conclusions by observation and experimentation, which can bring us closer to objective truths. In the case of evolutionary theory, it now has the support of hundreds of thousands of independent scientific tests conducted in many different contexts over the past 162 years since Darwin published “On the Origin of Species.” Darwin’s theories have withstood repeated scrutiny and they remain highly relevant to anyone interested in biology.
Regarding the specific example referred to by Hoyler, the symbiotic mutualisms that occur between plant roots and mycorrhizal fungi are indeed fascinating. There are entire unexplored ecosystems within the soil under a forest, and Suzanne Simard’s research has shed light upon the fascinating relationships among tree roots and their fungal partners. The interconnections between tree roots do indeed allow trees to take nutrients from one another. For example, a tree living in the shade can take nutrients from a tree living in the sun that is able to photosynthesize at a faster rate. But, this really should not be considered altruism. One tree is not making a selfless decision to give up resources to another tree. Instead, the interactions between tree roots should more accurately be viewed as a parasitism, with one tree taking resources from another.
Hoyler does make the good point that competition should not be thought of as the only interaction between individuals (or species) that has shaped their evolution. Cooperation and altruism are important interactions even from an evolutionary context. There are many good examples of altruistic behavior occurring among animals. For example, vampire bats will share a blood meal with another hungry bat when they return to the roost for the night. Acorn woodpeckers in the western U.S. hoard large stores of acorns that they share with other woodpeckers. Among many monkey species, individuals will develop close relationships with troop members to share food and grooming. Social insects (ants, bees, termites) develop amazing colonies in which labor and resources are shared.
Do these examples of altruism suggest that Darwinian theory is dead? No. In fact, detailed studies conducted by dedicated biologists have shown that every one of these examples fits neatly within Darwin’s theory of natural selection. In some cases (e.g., acorn woodpeckers and social insects) individuals are altruistic specifically toward close relatives. This is known as “kin selection.” By helping close relatives, an individual’s genes are passed on indirectly by those relatives. In other cases (e.g., vampire bats and monkeys), individuals develop close social relationships with one another in a process called “reciprocal altruism.” By helping one another, each individual increases their own chances of passing on genes to the next generation. Kin selection and reciprocal altruism were undoubtedly instrumental in shaping the evolution of human society.
Far from “losing its significance,” Darwinian theory is shedding light upon how altruism may have evolved in humans. Although it is important to acknowledge bias in science, it is important to avoid falling into the trap of assuming that past theories should be abandoned due to past bias.
Associate Professor of Biology
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