Scientists have divided the discussion of evolution. According to one faction, the previously known theory of evolution is very incomplete. What should be missing and why is this so controversial.
Evolution made man what he is today. But what are the reasons and drivers of human changes? Most people learn in school that Charles Darwin’s theory of evolution best describes the process. But even in biology, scientists disagree. In 2014, scientists published an important article related to the conflict and a new, expanded theory of evolution defended. The Guardian picked it up.
Natural selection: not the driving force in evolution?
Natural selection is considered universal. In short, this means that only individuals that are best adapted to the environment survive through several generations. This is how living things adapt and change, and thus evolution. The theory was developed by Charles Darwin in 1859. Today’s theory, based on Darwin’s findings, is called “standard evolutionary theory” (SET) or “synthetic evolutionary theory”. But for more and more scientists, this explanation is too simplistic or misleading.
In 2014, eight scientists published the article “Does Evolutionary Theory Need Rethinking?” (Does the theory of evolution need a rethink?). Her answer: “Yes, urgently.” Each of the scientists comes from innovative and cutting-edge scientific fields. Together they provide arguments for the approach that Darwin’s theory, and thus SET, is not comprehensive for all of evolution. the natural selection is not the strongest force in evolution.
Instead, they advocate a framework unspectacularly called Extended Evolutionary Synthesis (EES), which emerged in the 1950s and has been evolving ever since. In the research project of the same name, 51 world-renowned experts continue to test and research EES in an interdisciplinary way.
According to the EES, Darwin’s theory of evolution is not enough. One possible reason for the alleged omissions: he theorized natural selection without knowing what genes were.
According to the scientific paper, aspects missing in SET include:
- Plasticity: how the environment directly affects the properties of the organism; English: “plasticity”
- Developmental Bias: how physical development affects the occurrence of variations; English: “developmental bias”
- niche construction: how organisms change their environment to avoid natural selection; English: “niche construction”
- Extra-genetic inheritance: how organisms pass on more than genes to subsequent generations
For Darwin-based SET, these are the results of evolution. For supporters of EES, there are other drivers.
The Theory of Evolution: Is Darwin Still the Measure of All Things?
Darwin’s theory is well known, but very general. Over time, he was able to observe how living things adapt to their environment. He could not explain how this change was inherited. New insights and considerations complicated Darwin’s theory. In the 20th century, Gregor Mendel tried to understand heredity. Reproduction seemed to mysteriously shuffle genes. For example, a grandfather may have red hair and his son may not. The red hair may then reappear in his granddaughter. How does natural selection work when variations between two generations are not always passed on to the next?
According to Darwin, natural selection occurs insidiously, with small changes from generation to generation. He once wrote “Nature does not jump”: Nature does not jump. In 1910, zoologist and geneticist Thomas Hunt Morgan experimented with radioactive food for flies and thus showed that nature sometimes “jumps”: flies received mutated characteristics that were directly transmitted. This finding was difficult to reconcile with Darwin’s theory.
“Culture war” in biology
The impetus for the rethink originally came from molecular biology, where researchers look at individual molecules through a microscope. During the 20th century, they found arguments that natural selection is not the driving force: they discovered that the molecules in our cells mutate at a very high rate. Contrary to what the theory of evolution predicted, however, it was not only beneficial changes that were passed on and useless ones that were discarded at some point – mutations often remained nothing more than chance. Natural selection appeared to play little or no role, at least in this process.
Representatives of the theory of synthetic evolution and representatives of “non-Darwinian evolution” debated the importance of natural selection. To this day, the synthetic theory of evolution remains the focus of modern evolutionary biology.
“We’re not here to explain the trunk of an elephant,” British evolutionary biologist Brian Charlesworth told the Guardian. Charlesworth is widely regarded as one of the long-established proponents of the synthetic theory of evolution, but he does not believe that the theory of evolution needs to be radically revised. After all, evolution should be universal and focus on small factors that affect all living things.
In science, however, opinion groups with stubborn fronts are also formed. To some, the discussion between the two sides looks more like a culture war than a scientific disagreement—a battle between traditional theory and an expanded theory that incorporates new knowledge. However, biologist Eugene Koonin believes that researchers must get used to disagreement because there can be no single correct theory of evolution. “There is no one-size-fits-all theory,” he tells the Guardian.
The EES research project also believes that the new framework does not replace the old way of thinking, but that all findings should be used simultaneously to stimulate research on this topic. You can read more about it at extendedevolutionarysynthesis.com.
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