Charles Darwin is widely known for making the uncomfortable assertion that humans and apes are related. When he published his theory of evolution, he created a foundation on which everyone could grow. But Darwin's theory of evolution has actually experienced an evolution of its own and has incurred legacies both positive and negative.

One hundred and fifty years ago, the greatest work of the nineteenth century, as stated by many, was published. The Origin of Species by Means of Natural Selection by Charles Darwin sold 1,250 copies in its first day. Darwin had created the first intelligible and thoroughly substantiated theory of how species differentiate.

The Origin described how, through the ages, different species adapted to their environment so they would have a better chance of survival. Natural selection, the basic principle of evolution, states that parents of an organism will pass adaptations onto their offspring that will increase the likelihood of survival. If an organism lives longer, it will have a better chance to reproduce.

Even before he published The Origin, Darwin predicted the impact his book would have on the world. He knew that his theory would revolutionize science. He also anticipated that people would twist and corrupt it for their own purposes, which is exactly what happened. In preparation, Darwin wrote his supporters, asking for help defending his ideas. Thomas Huxley, Darwin's truest supporter, wrote, “I am sharpening up my claws and beak in readiness.” If Darwin were alive today, he would likely be horrified to see what evolved from the corruption of his theory.

In the late nineteenth century, a new form of thinking about society evolved. After Darwin published The Origin of Species, some believed that people should follow the rules of nature and compete for existence. The terms “social Darwinism” and “survival of the fittest” were coined. Darwin was outraged at this corruption of his theory.

Some social Darwinists believed that rich capitalists should be in charge. As a result, the poor would be ignored by the government, and those with physical or mental disabilities were considered to be inferior. Immigrants also were discriminated against. Many people used social Darwinism as justification for racism, imperialism, and capitalism.

The Ku Klux Klan is an extreme example of social Darwinism, along with imperialism, which is the practice of extending power or rule over another country or territory. For decades, people used Darwin's theory to justify horrible acts of discrimination, and unfortunately, it would only get worse.

World War II was one of the most terrible events of the twentieth century. Adolf Hitler and the Nazi party killed several million Jewish people, gypsies, homosexuals, and physically and mentally disabled people, and began a war that ravaged the world. If Darwin had been alive, he would have been horrified.

Hitler took Darwin's theory as a justification to create a “master race.” He proclaimed, “The stronger must dominate and not blend with the weaker, thus sacrificing his own greatness.” He believed Aryan features like blond hair and blue eyes were superior. People who agreed with eugenics believed in “selective breeding,” where only the “superior” group should have children and all others should be eradicated. Although Darwin's theory revolutionized science behind the scenes, to the public, it seemed as if Darwin and his theory had plunged the world into a nightmare.

Then Darwin's theory began to have a positive legacy in the field of science. Theodius Dobzhansky, a famous evolutionist, once said, “Nothing in biology makes sense except in the light of evolution.” Thanks to Darwin, we can now explain how two sets of DNA become one and pass traits down through generations. Darwin's theory can be applied to genetics, botany, agriculture, habitat preservation, endangered species, medicine, paleontology, and comparative anatomy. Even now, the full potential of his theory in medicine is still not wholly understood.

Recently, a new field called Darwinian medicine has evolved that includes the study of antibiotic resistance, which could totally change the way physicians deal with diseases. Penicillin was discovered in 1944 and antibiotics were believed to be “wonder drugs.” Every time a doctor prescribed antibiotics, the disease was cured. Recently, the efficacy of antibiotics has declined. Bacterial infections have started to become resistant to penicillin and other antibiotics, often because people misuse them. If you have strep throat and do not use the antibiotics for the prescribed length of time, you may not kill all of the bacteria. These bacteria can become resistant to the antibiotic and multiply, passing on the resistance. This occurrence is explained by ­natural selection.

When HIV was first recognized in 1981, little was known about its evolution. Unfortunately, in 1983, drug companies that received incentives to find a treatment for HIV produced many drugs that the virus became immune to, creating various strains of HIV. Since then, research into antibiotic resistance has given scientists clues to finding new treatments and vaccines for HIV. Scientists now realize that controlling this disease may be a matter of restricting its evolution, the exact model of natural selection. Since HIV is so quick to evolve, however, this is easier said than done.

Scientists have found that some people are resistant to HIV because they carry a mutation of the gene CCR5. Today, more than 20 percent of Europeans have this mutated gene, but for some reason, a very small percentage of the populations in Africa and Asia carry it. Scientists believe that centuries ago an epidemic similar to HIV invaded Europe, creating this resistant gene in the surviving population. By studying the gene, they hope to find new treatments for HIV.

With this new understanding of antibiotic resistance, many new protocols for treating diseases will evolve. Right now, the HIV and AIDS crisis in Africa is huge. Research into antibiotic resistance will help save many lives. Technically, all of these treatments and studies should be credited to Darwin and his theory of evolution.

Despite all the examples, applications, and benefits of Darwin's theory, some believe it is incorrect. Since Darwin published his theory, theologians and some religious groups have been in an uproar; The Origin contradicts traditional stories of creation. Some creationists say that life began 6,013 years ago. Evolutionary theory covers a much longer time period.

Today, the differences in the basic tenets of creationism and Darwin's theory are causing a conflict in school curricula. Some theologians believe that evolution should not be taught in schools because it can confuse a child's idea of God and His creation. Many trials have tried to determine if creationism or evolution should be taught in school, including the Scopes Monkey Trial in 1925, which creationists won, with the result that evolution was removed from the curriculum in public schools in Tennessee. From 1925 to 1930, creationists won many verdicts. After that, evolution began to reappear in textbooks and school curriculum. Many high school textbooks now describe evolution in depth. Today, evolution has been swaying the verdict in many trials, such as Kitzmiller v. Dover Area School District in 2005.

For a century and a half, Darwin's legacy has evolved to include a wide range of topics. From the smallest cell to the great blue whale, The Origin of Species explains how species evolve and adapt. Over the years, Darwin's theory of evolution has evolved too, through controversy. Some corrupted it into social Darwinism. Others put Darwin's theory to good use and revolutionized science. Due to Darwin, thousands of lives have been saved because of advances in medicine. Who knows what will evolve from his theory in the years to come.