6 Things That Darwin Did Not Know

Charles Darwin is known as the Father of Evolution
A. C. Cooper/De Agostini/Getty Images

There are so many scientific facts that scientists and even the general public take for granted in our modern society. However, many of these disciplines we now think are common sense were not even thought about yet in the 1800s when Charles Darwin and Alfred Russel Wallace were first putting together the Theory of Evolution through Natural Selection. While there was quite a bit of evidence that Darwin did know about as he formulated his theory, there were so many things we know now that Darwin did not know.

Basic Genetics

Mendel's Pea Plants. Getty/Hulton Archive

Genetics, or the study of how traits are passed down from parents to offspring, had not been fleshed out yet when Darwin wrote his book On the Origin of Species. It was agreed by most scientists of that time period that offspring did indeed get their physical characteristics from their parents, but how and in what ratios was unclear. This was one of the main arguments opponents of Darwin at the time had against his theory. Darwin could not explain, to the satisfaction of the early anti-evolution crowd, how that inheritance happened.

It wasn’t until the late 1800s and early 1900s that Gregor Mendel did his incredible game changing work with his pea plants and became the “Father of Genetics”. Even though his work was very sound, had mathematical backing, and was correct, it took quite some time for anyone to recognize the significance of Mendel’s discovery of the field of Genetics.

DNA

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DNA Molecule. Getty/Pasieka

Since there was no real field of Genetics until the 1900s, scientists of Darwin’s time were not looking for the molecule that carries genetic information from generation to generation. Once the discipline of Genetics became more widespread, many people raced to discover just which molecule it was that carried this information. Finally, it was proven that DNA, a relatively simple molecule with only four different building blocks, is indeed the carrier of all genetic information for all life on Earth.

Darwin did not know that DNA would become an incredibly important part of his Theory of Evolution. In fact, the subcategory of evolution called microevolution is completely based on DNA and the mechanism of how genetic information is passed down from parents to offspring. The discovery of DNA, its shape, and its building blocks have made it possible to track these changes that accumulate over time to effectively drive evolution.

 

Evo-Devo

Chicken embryo at later stage of development. Graeme Campbell

Another piece of the puzzle that lends evidence to the Modern Synthesis of Evolutionary Theory is the branch of Developmental Biology called Evo-Devo. In Darwin’s time, he was unaware of the similarities among groups of different organisms with how they develop from fertilization through adulthood. This discovery was not apparent until long after many advances in technology were available, such as high powered microscopes, and in vitro tests and lab procedures were perfected.

Scientists today can examine and analyze how a single celled zygote changes based on cues from the DNA and the environment. They are able to track similarities and differences of different species and trace them back to the genetic code in each ova and sperm. Many milestones of development are the same between very different species and point to the idea that there is a common ancestor for living things somewhere on the tree of life.

Additions to the Fossil Record

Australopithecus sediba fossils. The Smithsonian Institute

Even though Charles Darwin had access to quite a catalog of fossils that had been discovered up through the 1800s, there have been so many more fossil discoveries since his death that are very important evidence that supports the Theory of Evolution. Many of these “newer” fossils are human ancestors that help support Darwin’s idea of “descent through modification” of humans. While most of his evidence was circumstantial when he first hypothesized the idea that humans were primates and were related to apes, many fossils have since been found to fill in the blanks of human evolution.

While the idea of human evolution is still very much a controversial topic, more and more evidence keeps being discovered that helps strengthen and revise Darwin’s original ideas. This part of evolution will most likely stay controversial, however, until either all intermediate fossils of human evolution have been found or religion and people’s religious convictions cease to exist. Since the likelihood of either of the events happening is pretty much slim to none, there will continue to be uncertainty surrounding human evolution.

Bacterial Drug Resistance

Bacteria colony. Muntasir du

Another piece of evidence we have now to help support the Theory of Evolution is how bacteria adapts quickly to become resistant to antibiotics or other drugs. Even though doctors and medics in many cultures had used mold as an inhibitor of bacteria, the first widespread discovery and use of antibiotics, such as penicillin, did not occur until after Darwin died. In fact, prescribing antibiotics for bacterial infections did not become the norm until the mid-1950s.

It wasn’t until years after the widespread use of antibiotics became common that scientists understood that continuous exposure to the antibiotics could drive the bacteria to evolve and become resistant to the inhibition caused by the antibiotics. This is actually a very clear example of natural selection in action. The antibiotics kill off any bacteria that is not resistant to it, but the bacteria that is resistant to the antibiotics survive and thrive. Eventually, only bacterial strains that are resistant to the antibiotic will work, or “survival of the fittest” bacteria has taken place.

Phylogenetics

The Phylogenetic Tree of Life. Ivica Letunic

It is true that Charles Darwin did have a limited amount of evidence that could fall into the phylogenetics category, but much has changed since he first proposed the Theory of Evolution. Carolus Linnaeus did have a naming and categorizing system in place as Darwin studied his data and that helped him to formulate his ideas.

However, since his discoveries, the phylogenetic system has been changed drastically. At first, species were placed on the phylogenetic tree of life based on similar physical characteristics. Many of these classifications have been changed from the discovery of biochemical tests and DNA sequencing. The rearrangement of species have impacted and strengthened the Theory of Evolution by identifying previously missed relationships between species and when those species branched off from their common ancestors.

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Scoville, Heather. "6 Things That Darwin Did Not Know." ThoughtCo, Dec. 8, 2017, thoughtco.com/things-darwin-didnt-know-1224480. Scoville, Heather. (2017, December 8). 6 Things That Darwin Did Not Know. Retrieved from https://www.thoughtco.com/things-darwin-didnt-know-1224480 Scoville, Heather. "6 Things That Darwin Did Not Know." ThoughtCo. https://www.thoughtco.com/things-darwin-didnt-know-1224480 (accessed May 26, 2018).