The Theory That Shook The World

Other than Mendellson and his studies with genetics, Darwin has by far contributed the most to our modern science. From his theories on variation of species to his explanation of natural selection Charles Darwin has shocked the world by proving the world older than previously thought and creatures not immutable. In this present day these theories are as common belief as a simple mathematical equation such as two plus two equals four; but in the year eighteen hundred and fifty nine Darwin not only risked his reputation with these far fetched findings but also the risk of being excommunicated from the church. Previous to Darwin the thought had been that the world itself was only a few hundred years old and that all creatures were made by God in those seven days as they lived exactly today (Campbell p 421). Aside from past resistance, Darwin also comes under scrutiny still today as missing fossils which are to have been the bridge between a two familiar species are not yet found (Hitching p 3). Whatever the reason of belief or disbelief in Darwin's theories, he astounded the scientific world as well as the public and was able to convince many in the presence of a misguided past belief. This fact alone makes him one of the most important people of science ever. Charles Darwin was born in Shrewsbury-Shropshire, England on Feb 12, 1809 (GEA & RBi p 42). He was the fifth child in a wealthy English family with a history of scientific achievement with his paternal grandfather Erasmus Darwin who was a physician and a savant in the eighteenth century (GEA & RBi p 42). As a young boy Darwin already showed signs of his love for nature. When he was not reading about nature and its quirks he was out in the forest looking for wild game , fish, and insects (Campbell p 424). His father, although noting his son's interest in nature, felt that all the discoveries of the natural branch of science had been accomplished so he sent his son to medical school at Edinburgh instead (Bowler p 62). While Darwin was there, he could not keep his mind on his medical studies and decided to go and study at the University of Cambridge and become a clergyman. It was here that he was to meet two people who would change his future forever; Adams Sedgwick and John Stevens Henslow. Out of these two, Henslow turned into his second father and taught him to be meticulous in his observations of natural phenomena (GEA & RBi p 42). Upon graduating in 1831, Henslow suggested that he go on the Beagle as an unpaid naturalist on the scientific expedition (GEA & RBi p 43). Darwin gladly took Henslow's advice and set out on his voyage to South America to analyze and collect data that would later back up his evolutionary theories (Campbell p 424). Even as Darwin collected his data pertaining to what would become his theory on natural selection, many pre-existing views still had a hold on the scientific world as well as the public. The earliest recorded were those of Plato and Aristotle. Plato (427-347 BC) believed in two worlds; an illusionary which was perceived only through our senses and a real world which was ideal and eternal (Campbell p 422). Aristotle (384-322 BC), on the other hand, believed in a "scala naturae" in which each being has its own rung on a ladder which was permanent (Campbell p 422). Also, there were the present religious views that had to be dealt with as well as the ancient ideals. At that time many believed that animals and plants did not evolve because they were made holy and immutable by God on those seven days (GEA & RBi p 43). A person who was widely respected and also took some beliefs from Aristotle and present religion was Carolus Linnaeus (1707-1778). He believed species immutable and later became known as the father of modern taxonomy (Campbell p 422). Perhaps the largest barrier Darwin had was to convince the present day scientists of his findings in contrast to their pre-existing theories. The most common of the time was the catatropist theory. The definition of this theory was that "a violent and sudden change in the earth" had destroyed all creatures and each time this happened, God would come back down and recreate all the life in a seperate seven days (Webster p 131). This theory in itself seemed created for the soul purpose of covering up the reason for fossils existing and misled thought of the species being immutable (Campbell p 423). After Darwin's voyage on the Beagle, he had begun to develop his own theory of evolution. His personal definition of evolution was "in biology, the complex of processes by which living organisms originated on earth and have been diversified and modified through sustained changes in form and function" (JWV p 20). In regards to his research he had not only found evolution in the wild but in the domesticated sphere as well. Darwin held that all related organisms descended from a common ancestor and he found examples easily in common life (GEA & RBi p 43). One of these such examples were the domesticated pigeon. Darwin studied the skeletal and the live forms of the pigeons he had found. In doing so, he found them all to be related but for a small change in their phenotype. Phenotype being defined as follows "the actual appearance of an organism" (GEA & RBi-2 p 77). This small difference had been procured through the use of breeding and mutation. Perhaps the most notable would be the number of feathers in the fantail which ranged from twelve to forty feathers (Darwin p 42). Another example Darwin found in speciation by domesticated breeding were cows and horses. By the definition of a gene pool, "large random assortment of genes that may be rearranged", the farmers were able to produce a better breed of race horse or milk cow by breeding the best he had together (JWV p 21). This sexual evolution was just seen by the public as a way to produce the necessary end but Darwin held it as important evidence of evolution accessible for all to witness. And to back up this finding in the domesticated breeds as well as the wild he came up with his variability within a species. The definition to variability within a species held that 1) the offspring resemble the parents , but were not identical and 2) some differences in the parents were due solely to the environment but were often inheritable (JWV p 20). These two statements as well as the backup with clinical data helped to show that his theory was correct. Another area of variability was that of species in the wild. Perhaps Darwin's most famed findings to back his theory are "Darwin's finches". During his voyage on the Beagle he had observed thirteen different types of finches (Campbell p 425). These finches were found on seperate Galapagos Islands. Here each species of finch had at one time migrated to another island. In doing so the founder effect had been put into action. The founder effect being described as "when a few individuals of a population migrate and form a new colony having only a small gene pool causing a new species" (JWV p 23). Due to the diverse surroundings and limited gene pool the thirteen species had evolved from the original species that had migrated from the mainland to the islands. Darwin also observed other animals on these islands that were not found anywhere else in the world and began to doubt the churches teaching that species were immutable (Darwin p 29). The most controversial of Darwin's theory was that of natural selection. The term evolution was so controversial even Darwin did not use it but the phrase "origin of species" instead (Darwin p 27). Even though he did not term it evolution his views were definitely concrete and were laid out in a few simple sentences. These were the reasons why natural selection was a way of life and always had been. First, Darwin proposed that food supply was too little to support the large population thus eliminating those who were not strong enough to find food and survive. Second, parents adapted to a certain environment well would pass on favorable traits that would help the next generation survive, those without the trait would not survive. Third, each generation would become better adapted and if remaining in the same environment would become more capable of surviving. Finally, even with all the above working there were also factors of mutation, genetic drift, and bottle neck theories which contributed to the survival of the fittest (GEA & RBi p 43). Mutation being the most effective in changing a species had four factors by itself: 1) size of a population, 2) the length of a generation's life span, 3) the degree to which the mutation was favorable, and 4) the rate at which the same mutation appears in descendants (JWV p 21). Although most mutations are fatal, they are key in changing the genetic make up of an individual. Genetic drift is described as when a species for some reason begins to drift apart or come together to create a new specie or species. This is typically seen in today's fossil record when a present species is related to an extinct animal. [see fig. 1] Another of the traits of natural selection is the bottle neck theory. Here a population has been destroyed to such an extent that only a few survive. This limited population will recreate a new species based on its extremely limited gene pool and have a higher chance of carrying a fatal gene. All these factors working together simultaneously create the phenomena of natural selection. Darwin was not going to publish his findings but was forced to by a young man Alfred Russel Wallace who had come to the same conclusion after twenty years had passed. Although both scientists names were on the original copies of the Origin of Species Wallace regarded Darwin as the soul author. Within a year of writing, Darwin published what would be twenty years of research in 1859. Although, thoroughly backed up with painstaking research, it was still refereed to as "the book that shook the world" and in its first day of sales had sold out (GEA & RBi p 43). The immediate reaction in the science world was one of disbelief. The leading scientists of the day said that Darwin could not prove his hypothesis and the concept of variation could not be proved. Darwin was to be doubted for the next seventy years until the rediscovery of Mendel's pea plant experiments (GEA & RBi p 43). With these new findings on genetics, many scientists would take in account Darwin's work. Some of these people were to be a German zoologist named Ernst Mayr, a botanist G. Ledyard Stebbins, and paleontologist named George Simpson .

The Double Helix

The Double Helix A review of Watson, James D. The Double Helix. New York: Atheneum, 1968. James Watson's account of the events that led to the discovery of the structure of deoxyribose nucleic acid (DNA) is a very witty narrative, and shines light on the nature of scientists. Watson describes the many key events that led to the eventual discovery of the structure of DNA in a scientific manner, while including many experiences in his life that happened at the same time which really have no great significant impact on the discovery of the DNA structure. The Double Helix begins with a brief description of some of the individuals that played a significant role in the discovery of DNA structure. Francis Crick is the one individual that may have influenced Watson the most in the discovery. Crick seemed to be a loud and out spoken man. He never was afraid to express his opinion or suggestions to others. Watson appreciated Crick for this outspoken nature, while others could not bear Crick because of this nature. Maurice Wilkins was a much calmer and quieter man that worked in London at King's College. Wilkins was the initial person that excited Watson on DNA research. Wilkins had an assistant, Rosalind Franklin (also known as Rosy). Initially, Wilkins thought that Rosy was supposed to be his assistant in researching the structure of DNA because of her expertise in crystallography; however, Rosy did not want to be thought of as anybody's assistant and let her feelings be known to others. Throughout the book there is a drama between Wilkins and Rosy, a dram a for the struggle of power between the two. Watson's "adventure" begins when he receives a grant to leave the United States and go to Copenhagen to do his postdoctoral work with a biochemist named Herman Kalckar. Watson found that studying biochemistry was not as exciting as he hoped it would be; fortunately, he met up with Ole Maaloe, another scientist doing research on phages (Watson studied phages intensively while in graduate school). He found himself helping Ole with many of his experiments and soon he was helping Ole with his experiments more than he was helping Herman with his experiments. At first, Watson felt like he was deceiving the board of trustees by not studying the material that the board sent him to study. However, Watson felt justified because Herman was becoming less and less interested in teaching Watson because of Herman's current personal affairs (Herman and his wife decided to get a divorce). With Herman's lack of interest in teaching biochemistry, Watson found himself spending the majority of the day working with Ole on his experiments. While in Copenhagen, Herman suggested that Watson go on a spring trip to the Zoological station at Naples. It was in Naples that Watson first met Wilkins. It was also in Naples that Watson first became excited about X-ray work on DNA. The spark that ignited Wilkins' fire was a small scientific meeting on the structures of the large molecules found in living cells. Watson had always been interested in DNA ever since he was a senior in college. Now that he learned of some new research on how to study DNA, he had the craving to discover the structure of the mysterious molecule that he believed to be the "stuff of life". Watson never had the chance to discuss DNA with Wilkins that spring; however, that did not kill Watson's desire to learn about its structure. Watson's fire was further kindled by Linus Pauling, an incredibly intelligent scientist out of Cal Tech. Pauling had partly solved the structure of proteins. He discovered that proteins have an alpha-helical shape. Watson thought this was an incredible discovery! He was excited to research and learn about the DNA structure. Watson was worried about where he could learn more about DNA and how to solve X- ray diffraction pictures so the structure of DNA could be understood. He knew he could not do this at Cal Tech with Pauling because Pauling was too great a man to waste time with Watson and Wilkins continually put Watson off. Soon Watson became aware that Cambridge was the place he could get experience to solve the DNA problem. It was about this time that Watson's grant was about to expire. He decided to write Washington and request that his grant be renewed, continuing his studies in Cambridge rather than Copenhagen. Thinking that Washington would not deny his request, Watson packed up and went to Cambridge. He worked several months in Cambridge when finally he received a return letter from Washington. The letter stated that his grant would not be continued. Nevertheless, Watson decided to remain in Cambridge and continue his stimulating intellectual experience. It was in Cambridge that Watson first met Francis Crick. Here, Watson discovered the fun of talking to Crick. In addition, Watson was elated that he found someone in the lab that thought DNA was more important than proteins. Soon Watson and Crick found themselves having a daily lunch break together discussing many scientific topics, in particular, the unique aspects of DNA. As reports came to Watson and Crick about Paulings efforts to discover the structure of DNA, they began to feel pressure to discover the structure before Pauling did. However, Watson and Crick were at a disadvantage because they did not have access to some valuable research done by Wilkins and Rosy. This did not discourage Watson and Crick. With the limited information they had, they began to riddle over the possible structures of DNA. So far all the evidence they had (and also their intuition) indicated that DNA was a helical structure like proteins with either one, two, or three strands. Pauling was able to discover the alpha-helix by fiddling with models; by trial and error he came up with the correct structure. Watson and Crick decided to try model building as a method of solving the structure of DNA. Over a period of weeks to months, Watson and Crick fumbled around with DNA models. All did not go smoothly. One of the difficulties was that Watson and Crick did not have all the materials available to construct a model with the inorganic ions like DNA. With some manipulation of on-hand material they were able to create a model to their liking. Watson and Crick had constructed a beautiful three chain helix representing DNA. The next obvious step would be to check the parameters with Rosy's quantitative measurements. To their knowledge the model would certainly fit the general locations of the X-ray reflections. Upon completion, Watson and Crick were ecstatic about their accomplishment. To be the first to discover the structure of such an important molecule like DNA was going to make a major impact in the world. A phone call was made to Wilkins asking that he come to Cambridge to view the model and issue his opinion on its validity. The next day both Wilkins and Rosy came to Cambridge to view the model. Watson and Crick had their presentations prepared. They planned to dazzle their audience as they explained how they solved the complexity of the DNA structure. As their discussion went forth, Wilkins was skeptical on many aspects of the model. Rosy was completely dissatisfied with the model, especially with the fact that the model had Mg++ ions holding together the phosphate groups of the three-chain model. She noted that the Mg++ ions would be surrounded by tight shells of water molecules which contradicted the results she had gained on the water content of DNA molecules from her experiments. The rest of the day was spent trying to salvage what little argument Watson and Crick had. Over lunch was no success, neither did they prevail when they returned to the lab. Soon the day was over and Wilkins and Rosy returned to London. When Watson and Crick's supervisors heard of the failure with the model, they ruled that no further research would be done at Cambridge on DNA. For over a year Watson and Crick let DNA alone, only to be pondered upon while not working on other projects. That year Watson worked on researching the tobacco mosaic virus (TMV). A vital component to TMV was the nucleic acid, so it was the perfect front to mask his continued interest in DNA. Over time and hard work, Watson was able to show that some parts of TMV were helical in shape and thus decided to return to work on the structure of DNA. With more knowledge and expertise the research went forward with passion. Watson had seen an X-ray picture taken by Rosy that to him gave sure evidence that DNA was helical. Wilkins data only furthered his conviction. Watson and Crick were back at it again with a new fervor. They knew that there was a sugar phosphate backbone to the structure and it was held together somehow by the nucleic acids (adenine, thymine, cytosine, and guanine). Watson had a hunch that the shape was going to be a double helix. At first Watson thought the two backbones were held together by a like-with-like structure (adenine-adenine, thymine-thymine, etc.) holding the nucleic acids together with a hydrogen bonds. After about a day Watson realized that a like- with-like structure just was not possible. Watson knew that the amounts of adenine always equaled thymine and amounts of cytosine equaled guanine. With the help of Crick, they tried to construct a model by pairing adenine with thymine and guanine with cytosine. This fell together very nicely. After obtaining several opinions on the validity of their work they placed a call to Wilkins. Wilkins and Rosy came down and to the surprise of Watson and Crick, Wilkins and Rosy were immediately pleased with the model. After comparing results and measuring the model they decided that Wilkins and Rosy would publish a paper at the same time Watson and Crick published their paper, announcing their discovery. This was indeed an incredible discovery for the world, especially for the world of biology. The structure for the "stuff of life" was finally discovered. Watson and Crick went on to win the Nobel Prize for their work. Pauling who had worked so hard to discover the structure was not disgruntled by the fact that someone had beaten him to the discovery, but rather pleased that the problem was finally solved. Everyone was enthusiastic about the new discovery. This was excellent reading. Watson not only told the story of how the structure of DNA was discovered but he also let us in on the developments of parts of his personal life. He would speak of how he tried to have dinners at a school that was teaching young, pretty French girls English. He also spoke much of his relationship with Crick and Crick's wife, Odile. He made the book come alive and science seem more fun, breaking the stereotype of the scientist. I especially enjoyed how he described Rosy and her firm dedicated feministic attitude. The reader could feel sympathy for the tribulations Wilkins had to go through working with her. The book was an excellent account of the discovery of the structure of DNA. Throughout the text, Watson mostly eluded to the greatness of others rather than to his own greatness. Even though he played probably the most significant part in the discovery of DNA's structure he gave credit to those that have inspired him.

Future of Human Evolution

The Future of Evolution Evolution, the science of how populations of living organisms change over time in response to their environment, is the central unifying theme in biology today. Evolution was first explored in its semi-modern form in Charles Darwin 's 1859 book, Origin of Species by means of Natural Selection. In this book, Darwin laid out a strong argument for evolution. He postulated that all species have a common ancestor from which they are descended. As populations of species moved into new habitats and new parts of the world, they faced different environmental conditions. Over time, these populations accumulated modifications, or adaptations, that allowed them and their offspring to survive better in their new environments. These modifications were the key to the evolution of new species, and Darwin proposed natural selection or "survival of the fittest" as the vehicle by which that change occurs. Under Natural Selection, some individuals in a population have adaptations that allow them to survive and reproduce more tha n other individuals. These adaptations become more common in the population because of this higher reproductive success. Over time, the characteristics of the population as a whole can change, sometimes even resulting in the formation of a new species. Humans have survived for thousands of years and will most like survive thousands of more. Throughout the history of the Huminoid species man has evolved from Homo Erectus to what we today call Homo Sapiens, or what we know today as modern man.. The topic of this paper is what does the future have in store for the evolution of Homo Sapiens. Of course, human beings will continue to change culturally; therefore cultural evolution will always continue; but what of physiological evolution? The cultural evolution of man will continue as long as man can think; after all it's the ideas we think up that makes up our cultures. In a thousand years man might complete a 180 degree turn culturally (not to mention physiologically) and as seen by our fellow inhabitants of earth we would in essence be different beings. One can say that this new culture has chosen its ideas based on Natural Selection. One can see this in the spread of ideas in the past history of homo sapiens, the ideas which cause man to succeed are chosen such as science and democracy (the present growth of Islam is also worthy of mention, but would be a paper in itself). Lamarck's fourth law, that is, ideas acquired by one generation are passed on to the next, describes this transfer of ideas from one generation to another. The question is can humans evolve (physically), that is through changes of some sort to the general human gene pool, enough to be considered a different species sometime in the future. The answer to this is tricky. The answer is "yes" if there is no human intervention and "not likely" (or atleast controlled) if there is human intervention. The more interesting answer is the latter. The first answer deserves some mention. Through the subtraction or addition (that is through chance changes of some sort) of alleles (different forms of a characteristic gene) from the overall gene pool until homo sapiens are no longer is feasible. One might ask how and were this is occurring. The answer is human genes are changing all the time through radiation and spontaneous mutations (the latter more rapidly no than ever since the human population is now larger than ever) and one can see these changes to the overall gene pool in the disappearance of certain human tribes within parts of Africa and South America.. These tribes unfortunately take exclusive alleles with them. What about Natural Selection in present human culture. Some peoples are growing faster than others, for example-Chinese faster than any other in the present world, thus the large Chinese population. Therefore some group traits ae more common than others. Yet the loss of these alleles and the gain of these mutations offer marginal c ontributions to our species and thus have little or no effect. The first step in understand evolution in present terms is to mention genetic engineering (including genetic drift). The first step to understanding genetic engineering, and embracing its possibilities for society, is to obtain a rough knowledge base of its history and method. The basis for altering the evolutionary process is dependant on the understanding of how individuals pass on characteristics to their offspring. Genetics achieved its first foothold on the secrets of nature's evolutionary process when an Austrian monk named Gregor Mendel developed the first "laws of heredity." Using these laws, scientists studied the characteristics of organisms for most of the next one hundred years following Mendel's discovery. These early studies concluded that each organism has two sets of character determinants, or genes (Stableford 16). For instance, in regards to eye color, a child could receive one set of genes from his father that were encoded one blue, and the other brown. The same child could also receiv e two brown genes from his mother. The conclusion for this inheritance would be the child has a three in four chance of having brown eyes, and a one in three chance of having blue eyes (Stableford 16). Genes are transmitted through chromosomes which reside in the nucleus of every living organism's cells. Each chromosome is made up of fine strands of deoxyribonucleic acids, or DNA. The information carried on the DNA determines the cells function within the organism. Sex cells are the only cells that contain a complete DNA map of the organism, therefore, "the structure of a DNA molecule or combination of DNA molecules determines the shape, form, and function of the [organism's] offspring " (Lewin 1). DNA discovery is attributed to the research of three scientists, Francis Crick, Maurice Wilkins, and James Dewey Watson in 1951. They were all later accredited with the Nobel Price in physiology and medicine in 1962 (Lewin 1). "The new science of genetic engineering aims to take a dramatic short cut in the slow process of evolution" (Stableford 25). In essence, scientists aim to remove one gene from an organism's DNA, and place it into the DNA of another organism. This would create a new DNA strand, full of new encoded instructions; a strand that would have taken Mother Nature millions of years of natural selection to develop. Isolating and removing a desired gene from a DNA strand involves many different tools. DNA can be broken up by exposing it to ultra-high-frequency sound waves, but this is an extremely inaccurate way of isolating a desirable DNA section (Stableford 26). A more accurate way of DNA splicing is the use of "restriction enzymes, which are produced by various species of bacteria" (Clarke 1). The restriction enzymes cut the DNA strand at a particular location called a nucleotide base, which makes up a DNA molecule. Now that the desired portion of the DNA is cut out, it can be joined to another strand of DNA by using enzymes called ligases. The final important step in the creation of a new DNA strand is giving it the ability to self-replicate. This can be accomplished by using special pieces of DNA, called vectors, that permit the generation of multiple copies of a total DNA strand and fusing it to the newly created DNA structure. Another newly developed method, called polymerase chain reaction, allows for faster replication of DNA strands and does not require the use of vectors (Clarke 1). Genetic drift, another important factor when discussing evolution, is the study of statistical population genetics. ). One aspect of genetic drift is the random nature of transmitting alleles from one generation to the next given that only a fraction of all possible zygotes become mature adults. The easiest case to visualize is the one which involves binomial sampling error. If a pair of diploid sexually reproducing parents (such as humans) have only a small number of offspring then not all of the parent's alleles will be passed on to their progeny due to chance assortment of chromosomes at meiosis. In a large population this will not have much effect in each generation because the random nature of the process will tend to average out. But in a small population the effect could be rapid and significant. Suzuki et al. explain it as well as anyone I've seen; "If a population is finite in size (as all populations are) and if a given pair of parents have only a small number of offspring, then even in the absence of all selective forces, the frequency of a gene will not be exactly reproduced in the next generation because of sampling error. If in a population of 1000 individuals the frequency of "a" is 0.5 in one generation, then it may by chance be 0.493 or 0.0505 in the next generation because of the chance production of a few more or less progeny of each genotype. In the second generation, there is another sampling error based on the new gene frequency, so the frequency of "a" may go from 0.0505 to 0.501 or back to 0.498. This process of random fluctuation continues generation after generation, with no force pushing the frequency back to its initial state because the population has no "genetic memory" of its state many generations ago. Each generation is an independent event. The final result of this random change in allele frequency is that the population eventually drifts to p=1 or p=0. After this point, no further change is possible; the population has become homozygous. A different population, isolated from the first, also undergoes this random genetic drift, but it may become homozygous for allele "A", whereas the first population has become homozygous for allele "a". As time goes on, isolated populations diverge from each other, each losing heterozygosity. The variation originally present within populations now appears as variation between populations (Suzuki 704). The evolution of man can be broken up into three basic stages. The first, lasting millions of years, slowly shaped human nature from Homo erectus to Home sapiens. Natural selection provided the means for countless random mutations resulting in the appearance of such human characteristics as hands and feet. The second stage, after the full development of the human body and mind, saw humans moving from wild foragers to an agriculture based society. Natural selection received a helping hand as man took advantage of random mutations in nature and bred more productive species of plants and animals. The most bountiful wheats were collected and re-planted, and the fastest horses were bred with equally faster horses. Even in our recent history the strongest black male slaves were mated with the hardest working female slaves.

The Relationship between yeast fermentation and food concentr

In this experiment different concentrations of sucrose were tested to determine which leads to the most respiratory activity in yeast. Yeast is a heterotrophic anaerobic fungus which lacks chlorophyll. Yeast is used commercially to ferment the sugars of wheat, barley, and corn to produce alcohol, and in the baking industry to raise or expand dough. Yeast or alcoholic fermentation is the anaerobic process of respiration by which sugars, such as glucose and sucrose, are converted into ethanol and carbon dioxide (CO2 ). This process is illustrated in the following equation: yeast C12H22O11 + H2O ---> 4 CH3CH2OH + 4 CO2 sucrose + water (yields) ethanol + carbon dioxide In order to determine what concentration of sucrose and water leads to the most respiratory activity, ten large test tubes were set with different concentrations by the process of serial dilution. The first test tube was filled with 40 ml of 60% sucrose solution. Then, the nine remaining test tubes were serially diluted, so that the sucrose concentration ranged from 30% to 0.12%. The hypothesis in this expriment was that the most respiratory activity would take place with 60% sucrose concentration. Since yeast fermentation requires sucrose and water, aproximately equal proportions of both would yield to the most respiratory activity. Once the sucrose concentration was serially cut to the desired level, the experimenter added 5 ml of yeast suspension to each one of the ten test tubes. Then, ten small test tubes were placed invertedly into each one of the large test tubes, making sure no air bubbles remained within the small tibes. The test tubes were left 24 hours, allowing for fermentation to take place. But, no respiratory activity was detected. In previous experimentation, it was found that yeast fermentation did take place in different molasses concentrations. Since, molasses contains large quantities of sucrose, it was assumed that different concentrations of pure sucrose would yield similar results, when mixed with yeast. However, this was not the case. The probable explanation is that in order for fermentation to take place, an enzyme is needed to break down sucrose --a disacharide-- into glucose and fructose --monosacharides. This enzyme is present in molasses, but it is absent in the sucrose solution.

Genetic Engineering

Bioengineering, or genetic engineering is an altering of genes in a particular species for a particular outcome. It involves taking genes from their normal location in one organism and either transferring them elsewhere or putting them back into the original organism in different combinations. Most biomolecules exist in low concentrations and as complex, mixed populations which it is not possible to work efficiently. This problem was solved in 1970 using a bug, Escherichia coli, a normally innocuous commensal occupant of the human gut. By inserting a piece of DNA of interest into a vector molecule, a molecule with a bacterial origin of replication, when the whole recombinant construction is introduced into a bacterial colonies all derived from a single original cell bearing the recombinant vector, in a short time a large amount of DNA of interest is produced. This can be purified from contaminating bacterial DNA easily and the resulting product is said to have been "cloned". So far, scientists have used genetic engineering to produce, for example: • improve vaccines against animal diseases such as footrot and pig scours; • pure human products such as insulin, and human growth hormone in commercial quantities; • existing antibiotics by more economical methods; • new kinds of antibiotics not otherwise available; • plants with resistance to some pesticides, insects and diseases; • plants with improved nutritional qualities to enhance livestock productivity. Methods: • Manipulation of the Gene pool, which is related to Hybridization which is the breeding of species but the species are not the same but they are related. • Chain reaction is the production of many identical copies of a particular DNA fragment. • The utility of cloning is important, it provides the ability to determine the genetic organization of particular regions or whole genome. However, it also facilitates the production of naturally-occurring and artificially-modified biological products by the expression of cloned genes. • Insertion of selectable marker genes to pick out recombinant molecules containing foreign inserts • Removal or creation of useful sites for cloning • Insertion of sequences which not only allow but greatly increase the expression of cloned genes in bacterial, animal and plant cells. • The ability to take a gene from one organism (e.g. man or tree), clone E. coli and express it in another (e.g. a yeast) is dependent on the universality of the genetic code, i.e. the triplets of bases which encode amino acids in proteins:

Leprosy

Leprosy or Hansen's disease, is a chronic, infectious disease that mainly affects the skin, mucous membranes, and nerves. A rod shaped bacillus named Mycobacterium leprea, causes the virus. Mycobacterium leprea is very similar to the bacillus that causes tuberculosis. The reason Leprosy is also known as Hansen's disease, is because it was first identified in 1874 by a Norwegian physician named Gerhard Henrik Armeur Hansen. Leprosy appears in both the Old and New Testaments. In the bible Leprosy was not the disease that is recognized now, but as various physical conditions that were nothing like the disease. A punishment from God was what these conditions were considered to be. The victim was said to be in a state of defilement. This Hebrew term was translated as lepros, which the word leprosy came from. The disease's probable origin was the Indus Valley that is located in India. Leprosy spread from there to the Mediterranean region and North Africa, then all of Europe was affected. This disease is much less common now, as the world case count has dropped below 1 million. During 1995 about 530 000 new cases of leprosy were discovered. It is obvious that third world countries have way more cases as India, Indonesia, and Myanmar account for almost 70% of the cases reported in the world. 5500 know cases of Leprosy still exist in the US, and about 200 cases a reported annually. Tests to produce leprosy in experimental animals, have not been successful as of yet. Though the organism can be grown in Armadillos, several laboratories have been reported cultivating leprosy in the test tube. Loss of sensation in a patch of skin is often the first symptom that Leprosy displays. In the lepromatous form, large area's of the skin may become infiltrated. The mucous membranes of the nose, mouth, and throat may be invaded by large numbers of the organism. Because of damage to the nerves, muscles may become paralyzed. The loss of sensation that accompanies the destruction of nerves may result in unnoticed injuries. These may result in secondary infections, the replacement of healthy tissue with scar tissue, and the destruction of bone. The classic disfigurements of Leprosy, such as loss of extremities from bone damage or the so-called leoline facies, a lionlike appearance with thick nodulous skin, are signs of advanced disease, now preventable with early treatment. For many years the use of chaulmoogra oil was used for the treatment for Leprosy. Today drugs such as dapsone, rifampin, and clofazimine are used alongside a healthy diet. If killed too quickly, bacilli may cause a systematic reaction. The reaction is called erythema nodosum leprosum, or ENL may cause progressive impairment of the nerves. Corticosteroids control such reactions. Of all contagious diseases Leprosy is maybe the least infectious. New patients are rarely ever quarantined. Most patients are treated on an outpatient basis. A Leprosy vaccine is currently under development.

Biome Broadcast

LANCASTER / PENNSYLVANIA This morning Darian, Danny, Laura, and I were bored so we decided that we would all go on a hike at Blue Ridge Mountain. All of us went home, got our hiking equipment, and packed a lunch. We then met at my house. I drove all of us up to Blue Ridge Mountain. We got there in a half hour it was around 10:30 AM. It was probably one of the most beautiful days we had all year, it was around seventy to seventy five degrees and there was barely any humidity. Even though we have all four seasons and varied amounts of precipitation throughout the year it felt like it was either a scorching humid summer day or it was a freezing snowy winter day. It felt like we only had two seasons all year either summer or winter. When we stepped out of the car we could see and hear birds singing. We could also smell, hear, and see the beautiful trees swaying in the gentle breeze. Pictures of a robin and a cardinal that we saw while stepping out of the car. We all got our gear out of the car and walked over to the trails. We had to decide what trail to take. We had three choices the first trail was half a mile long, the second trail was two miles long, and the third trail was four miles long. Since it was such a beautiful day we all decided to take the third trail that was four miles long. We started hiking around 11:00 AM. While we were hiking we heard wings flapping, we all turned and saw a robin fly towards the ground, pick up a worm, and feed it to her babies. Everyone thought that it was cute. After, we watched the robin for a while we continued hiking until 12:30 PM. Everyone was hungry so we decided to find a spot to eat our lunches. We found a perfect spot, it had a great view, a patch of beautiful dandelions, and a big beautiful maple tree to sit under. A picture of the great view we had during lunch. A picture of one of the many dandelions that were in the patch that we were sitting next to during lunch. A picture of the maple tree we sat under while eating lunch. We all sat down on the big blanket that we had brought along and ate our lunches. Laura went over and picked a dandelion and smelled it. We talked for a while and admired how big and beautiful the Blue Ridge Mountain was. We finished having lunch around 1:30 PM. We then started hiking again. As we were hiking we heard a splashing noise, we could not really identify what it was. We walked toward the noise and encountered some ruff terrain. We finally found what we have been hearing. It was several bears It was several bears trying to catch fish in a stream. One of the bears caught a fish and all of the other bears ran over to see if they could get some but it was to late because the bear had already devoured the fish. A picture of the bears trying to catch fish. We decided to move on and not interfere with the bears because that is not a situation we wanted to be in. As we moved on we saw a rattlesnake eat a mouse. We were about fifty feet away though because if he were to bite one of us on top of this mountain with nobody to help us our chances of survival were pretty low. As we walked on we saw a nest of baby rattlesnakes we looked at them from a safe distance when all of a sudden the mother of the rattlesnakes shot out from behind a rock. We all ran for our lives! We ran for a good five minutes before the rattlesnake stopped chasing us. Nobody was bit thank god. A picture of the baby rattlesnakes that we saw. But we had a big problem we were totally lost! We had traveled pretty far off the trail while the rattlesnake was chasing us. We all decided to travel down the mountain because it seemed to be the most logical way because we hiked up the mountain so if we hiked down the mountain we would probably make it to the car. We started to make our way down the mountain. As we were making our way down the mountain Laura tripped and rolled down the mountain about ten feet. We all ran over to her and discovered she had broke her leg. Darian and I went to find some branches so we could make a splint for Laura's leg. We found some branches and went back over to Danny and Laura. We assembled a splint and put it on Laura's leg. It was just strong enough for her to be able to walk. So we continued making our way down the mountain and luckily we found a compass! We knew we had to travel north because that was the way the trail traveled. So we started to hike north. We eventually made our way back to the trail. We saw some other people that were hiking. They saw we needed help and they gladly provided us with their assistance. They helped us get back to my car. I got in my car and drove to the nearest phone. I called an ambulance and drove back to the mountain. We all waited for the ambulance to come. When the ambulance arrived they put Laura in the back and took her off to the hospital. All of us watched the ambulance drive off into the sunset. A picture of the sunset by the Blue Ridge Mountain.