Everything today is a product of evolution. From apes to Homo sapiens, humans went from crawling on all fours to walking on two flat feet. Mammals have evolved from tiny rodents to a diverse category of cats, horses, dogs, elephants, dolphins and many others. However, there would be no evolution without natural selection; it is what sets everything apart and gives unique genes a purpose. Without it, species would not have the chance to adapt and thrive in the world's changing climates. Polar bears have thick coats to keep them warm in the Arctic, cacti have spikes to protect them from harsh desert environments, and dolphins use sonar to communicate and detect objects underwater. However, traits that help some species survive can, in turn, harm others. For example, humans have been battling disease-causing bacteria for hundreds of years. When antibiotics appeared, it seemed that humans were winning the war against disease. However, recently, harmful bacteria are making a comeback and are slowly, but surely, becoming resistant to the many antibiotics available today. Thanks to evolution and natural selection, bacteria have mutated and multiplied so quickly that scientists have struggled to keep up. Soon the world could face another pandemic, and those of the past have left only a small dent in the human population. Although evolution is impossible to stop, humans have also played a role in speeding up the process of forming antibiotic-resistant bacteria; From misdiagnosing illnesses to throwing old antibiotics in the trash, people everywhere play a role in winning or losing this battle against bacteria. Antibiotics are essential to fight diseases caused by pathogenic bacteria....... middle of article......gy 11.1 (2010): 2-12. Premier Academic Research. Internet. November 21, 2011. Kaufman, Gerri. “Antibiotics: mode of action and resistance mechanisms.” Art and Science 25.42 (2011): 49-55. CINAHL Plus with full text. Internet. November 9, 2011. Kropinski, Andrew. “Phagotherapy – Everything old is new again. » The Canadian Journal of Infectious Diseases and Medical Microbiology 17.5 (2006): 297-303.Pub Med. Internet. November 22, 2011. O'Connor, EM and RF Shand. “Halocins and sulfolobicins: the emerging history of archaeal protein and peptide antibiotics.” Journal of Industrial Microbiology and Biotechnology 28.1 (2002): 23-30. Premier Academic Research. Internet. November 21, 2011. United States. Government Accountability Office. “Antibiotic resistance data gaps will persist despite steps taken by HHS to improve surveillance. » GAO.gov.Government Accountability Office, June 1, 2011. Web. November 9. 2011.