Ap Biology Paper

August 20, 2012 AP Biology Paper thing Daniel Gildenbrand Many scientists have contributed to the subjects of nature, evolution, medicine, and to the development of how experiments are executed. In this essay I will go over four scientists, their experiments, and how those experiments benefited the scientific community and the way we currently live our lives. These four scientists greatly contributed to science and were arguably the greatest contributors to their field of study.

First, we have Francesco Redi and his famous experiments challenging the previous assumption that maggots underwent “spontaneous generation”, a theory about the formation of living organisms without descent from similar organisms, and naturally spawned from rotting meat. Redi disproved this theory with his experiments. In one of those experiments, Redi took three groups of jars: in the first jar of each group he put an unknown object; in the second, a dead fish; and in the third, a rotting piece of meat.

The first group of jars was left open with no lid, the second group was covered in a woven piece of gauze, so that only air could get into the jar, and the third group was firmly sealed with a lid. After a few days of wait, Francesco noted that maggots appeared in the open jars where he saw flies had landed. The group of jars covered with the gauze had maggots on top of the gauze because the flies could smell the rotting meat so they laid their eggs there. Finally, he observed jars sealed with a lid had no maggots.

With this experiment he disproved the theory of abiogenesis. His contribution to the scientific community did not end with just the results of his experiments as he was credited with the development of the “controlled experiment. ” Controlled experiments changed the way we conduct experiments and greatly increased the accuracy of our results. The famous quote “Omne vivum ex ovo” (“All life comes from an egg”) is commonly associated with Redi’s experiments. A great contributor to the field of medicine and microbiology was Louis Pasteur.

He was famous for his experiments with micro-organisms and for inventing the S-flask, which is now of great use in scientific experiments. Louis’ experiments saved the silk industry, and solved problems with the manufacture of alcoholic drinks. Most importantly, Pasteur invented the process now known as pasteurization. While working with the germ theory, which he bettered with his research, Pasteur proved that micro-organisms such as bacteria were responsible in the souring of alcoholic drinks such as beer and wine.

He also discovered that microbes where infecting silk worm eggs and advocated that only disease-free eggs should be selected, which saved the industry. Another one of Pasteur’s accomplishments was when he confirmed the disproval of abiogenesis through his experiments. In the experiment, he put exposed boiled broth into two groups of S-flasks, which he invented to slow the growth of bacteria in test tubes. Then, he covered one of the groups of flasks with a filter designed to prevent any particles from entering the tube.

The other group was group of S-flasks was left alone (the S-flasks also only allowed a minimal amount of particles to enter the tube). He concluded that bacteria only grew in the flasks after they were broken open; therefore, the microbes had to come from the outside, in the form of spores on dust particles. To counter the growth of these bacteria, he developed “pasteurization” which is a process that kills bacteria within a liquid by heating then cooling the liquid. Pasteurization is now used just about anywhere beverages are manufactured to prevent any bacteria from entering the products.

Finally, Louis Pasteur’s arguably greatest contribution to science was bettering the concept of vaccination. When Pastuer was working on a problem causing chickens to die from a virus called “chicken cholera” on a farm, he exposed some of the healthy chickens to a weaker form of the virus. After returning from a month-long vacation, Louis discovered that the chickens did not die from the disease, like the others, but had actually grown immune to the disease and were completely healthy.

He applied the same principle of vaccination to a quickly spreading epidemic called anthrax. Louis Pasteur’s contributions to science were vast and if we think about it, his research has forever changed the way that we live our lives today. Charles Darwin was an English naturalist who was dubbed the father of evolution. His work included establishing the fact that all species descended from common ancestors and describing a process he called natural selection in which different species struggled for life, leaving only the ones that adapted better to survive.

Darwin has often been called one of the most influential figures in human history. His work undoubtedly affected people’s view on life and his theory of evolution transformed the way we think about the natural world. Darwin collected his research from many different places but his most influential research was gathered along his voyage on the Beagle. In 1831 Darwin tagged along the ship The Beagle on a survey voyage. When he got to the Galapagos Islands, he noticed that each island had similar finches that had their own distinctive features.

He then noticed that these features corresponded with the environment that the birds lived in and what they had to hunt. He explained the situation with the theories of evolution and natural selection. He stated that the finches had originated from a similar ancestor and had evolved their characteristics to adapt to each sub-environment on the islands. Then, by natural selection, the finches that were better suited for their environment where left to breed and thrive on the islands. This is what we would call today, “Survival of the fittest. What Darwin accomplished with his research is vital to the scientific community and what we learn today. His work explains why many things exist as they do and how some things came to be. Finally, we had Sir Alexander Fleming, who discovered the “wonder drug” penicillin. Fleming had discovered the world’s first anti-biotic, or bacteria killer. Penicillin is a drug that kills bacteria in many forms and is widely used in medicine and is essential in healing infections. As important as penicillin may be, it was found in a very strange way.

When Fleming was leaving his laboratory for a vacation, he had stacked all his cultures of staphylococci on a bench in a corner of his laboratory. When he returned, he started to show some of the samples to his lab assistant and randomly noticed that one of the samples had grown a mold. He thought nothing of it until he also noticed that the mold had killed the staphylococci sample that was in the dish. Fleming saw that this mold had great potential. He spent several weeks growing more of the mold and, with the help of a colleague, he figured out that it was a Penicillium mold.

He continued to run experiments with the mold and figured out that it killed many different types of harmful bacteria. But the most important characteristic of the mold was that it did no harm to the human body. Since Fleming was not a chemist, he could not isolate the actual antibacterial element within the mold and use it as medicine. Later on though, two chemists by the names of Florey and Chain managed to make penicillin a usable product. Fleming’s discovery of penicillin greatly benefited the evolution of medicine and has been a vital asset in fighting bacteria and illness.

Francis Redi, Louis Pasteur, Charles Darwin, and Alexander Fleming each greatly benefited the scientific community. Their research and discoveries allowed for great advancements in medicine, knowledge, and helped shine light on things previously unknown. Francesco Redi and Louis Pasteur both disproved the theory of spontaneous generation. Charles Darwin changed the way we view species and the natural world with his theories of evolution and natural selection. Lastly, Alexander Flemings advanced field of medicine by discovering the miracle drug of penicillin.

Whether it was by Darwin giving us new knowledge on the natural world or by Redi, Louis, and Pasteur pushing medicine further, these fours scientists greatly improved our lives and forever changed the way we live them. Bibliography Francesco Redi Meat and Maggots 1. “Francesco Redi and Controlled Experiments. ” The Church and Science:Conflict or Complement. N. p. , n. d. Web. 7 Sept. 2012. <http://www. scientus. org/Redi-Galileo. html>. 2. “Redi Experiment. ” Kent School District. N. p. , n. d. Web. 7 Sept. 2012. <http://www1. kent. k12. wa. us/staff/timly 3. “Francesco Redi and Spontaneous Generation.  Louis Pasteur – The Life, Work and History – Microbiology, Chemistry, Fermentation and Beer. N. p. , n. d. Web. 7 Sept. 2012. <http://www. pasteurbrewing. com/Articles/spontaneous-generation/francesco-redi-and-spontaneous-generation. html>. Louis Pasteur Micro-organisms and the flask 1. “Louis Pasteur Biography. ” Bio. com. A&E Networks Television, n. d. Web. 07 Sept. 2012. <http://www. biography. com/people/louis-pasteur-9434402>. 2. “BBC – History – Louis Pasteur. ” BBC – Homepage. N. p. , n. d. Web. 7 Sept. 2012. <http://www. bbc. co. uk/history/historic_f 3.

Bellis, Mary. “Louis Pasteur – Germ Theory of Disease. ” Inventors. N. p. , n. d. Web. 7 Sept. 2012. <http://inventors. about. com/od/pstartinv Charles Darwin Evolution, Survival, Natural Selection 1. “BBC – History – Charles Darwin. “BBC – Homepage. N. p. , n. d. Web. 7 Sept. 2012. <http://www. bbc. co. uk/history/historic_figures/dar 2. “Darwin’s Theory Of Evolution. “Darwin’s Theory Of Evolution. N. p. , n. d. Web. 7 Sept. 2012. <http://www. darwins-theory-of-evolution. com/>. 3. “Darwin’s Theory. ” BioWeb. N. p. , n. d. Web. 7 Sept. 2012. <http://bioweb. cs. earlham. du/9-12/evolution/HTML/theory. html>. Alexander Fleming Molds and Penicillin 1. Rosenberg, Jennifer. “Alexander Fleming Discovers Penicillin. ” 20th Century History. N. p. , n. d. Web. 7 Sept. 2012. <http://history1900s. about. com/od/medicaladva 2. “Sir Alexander Fleming – Biography. “Nobelprize. org. N. p. , n. d. Web. 7 Sept. 2012. <http://www. nobelprize. org/nobel_prizes/medicine/laureates/1945/fleming-bio. html>. 3. “Alexander Fleming and Penicillin. “History Learning Site. N. p. , n. d. Web. 7 Sept. 2012. <http://www. historylearningsite. co. uk/alexander_fleming_and_penicillin. htm