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Thursday, August 12, 2010

Scientific Method

Thursday, August 12, 2010 - 2 Comments

Science is an organized and systematic knowledge which is gathered through observations inquiry and experiments. Since function in the realm if matter and energy. The methods of science cannot be applied in areas of investigation involving the aspects of human mind and spirit. Scientific knowledge is neither inherently good nor bad. Same scientific knowledge that gave the nuclear energy and nuclear medicines also gave the nuclear wastes problems for the workers and environment.

            Make Observations
            Formulate a hypothesis
            Design a controlled experiment
            Collect data
            Interpret data
            Draw conclusions
            Consult prior knowledge

Biological method of study: In order to resolve a specific biological problem certain scientific method is adopted in which conclusion or answers to various related questions of biological problem are drawn from observation and experiments. Summary of this method is explained in the flow chart. Here malaria is being considered as an example of biological problems.
(1) Observations: After determination of specific biological problem observations are made to collect relevant information or data. Malaria is dreadful disease whose history goes back to pre birth time of Christ. In ancient days there was no treatment of malaria and large number of people used to die due to this disease. Some historians have attributed the downfall of Greek and Roman empires to this disease. The scientists were struggling to know the cure or treatment of this disease from ancient times. In those days back of cinchona tree was considered to be effective remedy against malaria. At the same time the bad air coming from stagnant ponds was considered to be possible cause of malaria. Some volunteers drank dirty water from the ponds to find the cause but failed. In 1878 French army physician Lavern found small microscope thread like organisms in the blood of malaria patients. These thread like organisms were not present in the blood of healthy person. He called this micro-organism as malarial parasite that was later described and given the name Plasmodium. By this time four major observations for malaria were recorded.
(i) Malaria and marshy places were some how associated. (ii) Quinine from cinchona bark was an effective remedy for malaria. (iii) Malaria parasites always have malarial parasite in their blood. (iv) Drinking marshy water did not cause malaria.
(2) Hypothesis: Observations alone do not usually provide solution to scientific problems. In most of the cases one or more suitable propositions are made on the basis of the observations. These propositions are called hypothesis. The hypothesis are tested by scientific method and the scientific hope that one of the hypothesis would turn out to be the solution of scientific problem under study good hypothesis has the following merits:
(i) It is close to the observed facts.
(ii) The deductions can be drawn from it.
(iii) Deduction should be suitable for testing experimentally.
(iv) Results whether positive or negative should be reproducible.
Every year about 200 million people get malaria and about two million die of it in which most of them are children and pregnant women. Main hypothesis is “Plasmodium is the cause of malaria”. Hypothesis can not be directly tested. Some deductions are made from the hypothesis which is put to test through experimentation.
(3) Deduction: Many deductions may be drawn from hypothesis. Testing one deduction and finding it correct does not mean the hypothesis is correct. The validity of hypothesis is more supported if many deductions confirm the hypothesis. Symptoms of deductions are (i) High fever (106°F) with shivering (ii) Headache and nausea (iii) High breathing rate with increased heart beat (iv) Heavy sweating sometime after high fever leading to normal or below normal temperature (v) Person feels fatigued and exhausted (vi) Recurrence of all above symptoms after specific intervals in absence of proper treatment. Deduction can be tested by experiment.
(4) Experiment: Experimental group is the group of those people who are affected but the real cause is now known e.g. group of malarial patient on the other hand a group of un affected people is called control group e.g. group of healthy people. Both groups are kept in identical conditions. In order to find out the real cause of malaria, experts examined the blood of about 100 malaria patients termed as experimental group, and examined blood of 100 healthy persons known as control group.
(5) Results: Most of the malarial patients had plasmodium in their blood where as the blood of healthy persons was free of plasmodium. These results verified the deduction and thus the hypothesis i.e. the plasmodium is the cause of malaria was proved to great extent. AF. A King in 1883 suggested “Mosquitoes are involved in spreading the malaria”. His observations are (i) People who slept out doors in open spaces suffered more frequently from malaria than those who slept indoors (ii) People who slept under mosquito net did not suffer from malaria. (iii) Persons who slept near smoke fire also did not suffer from malaria.
Opinions of King were further tested by Ronald Ross in 1880 who performed different experiments in order to establish relationship between the work of Lavern and King. After discovery that plasmodium is the cause of malaria, Ronald Ross tried to find out how plasmodium entered the blood of man. He observed that plasmodium was growing and multiplying in the stomach of female. Anopheles mosquito that had bitten a person ill with malaria Ross selected sparrow instead of man for experiments. Malarial parasite (plasmodium) completes its life cycle in two steps. Asexual reproduction is completed in human body and sexual reproduction completed in the body of female Anopheles mosquito. Ross proved that mosquito is the cause of malaria that transferred plasmodium from the blood of one sparrow to the other.

Environment and World Resources

Common environment unites life. In some parts of the world, the land is recovering from decades of abuse. We can compare polluted lake Eric of 1960s to much cleaner lake of 1990s. A lake once unfit for fishing and other recreational uses is now used for these purposes. Tracts of land have been set aside for use as natural and wilderness areas. Many non biodegradable (the substances that cannot be broken down by biological processes) substances have been taken out of market place. These developments and others like them offer hope. Some societies are beginning to realise that all life shares dependence on earth’s resources. Even though there is hope many societies have not abandoned those values that treat land, water and air commodities that can be brought and sold or neglected and abused. The problems are most acute in the developing counties that are striving to attain the same wealth as industrialized nations. In the process the land suffers, population growth goes unchecked, tonic wastes are dumped plant and animal species becomes extinct and deserts and famine expand. Government and private agencies like world watch institute have undertaken large-scale evolution of environmental health of the world. The results of such studies deserve the serious attention of every concerned citizen.
Global over population in some cause of global problems. Among these human population growth is expected to continue in twenty first century that is around 92% in less developed countries.
Since majority of population will be of child bearing age, growth could even be faster in 21st century. As the human population grows, the disparity between wealthiest and poorest nations will increase.
World Resource: Human over population is stressing world resources. Although new techniques continue to increase food production, most food is produced in industrialized countries that already have high per capita food consumption. Maximum oil production is expected to continue into new millennium to meet the ever increasing needs of energy. Continued use of fossil food adds more carbon dioxide to the atmosphere, contributing to the green house effect and global warning.
Deforestation: The process of cutting or removing the forests of large areas of the world results from continued demand for forest products and fuel. Thus trend contributes to the green house effect causes severe regional water shortage and results in the extinction of many plants and animal species especially in tropical forests. Forest presentation would result in the identification of new species of plants and animals that could be important human resources, new foods and drugs, building material and predators of the pests. Nature also has intrinsic value that is first important as its provision of human resources.
Solution: Above mentioned problems cannot be easily solved, famine and other problems, that accompany over production steps should also be taken towards improved social and economic conditions and better resource management.

Genetic Unity, Evolutionary Oneness and Diversity of Life

All life is based on fundamental molecule Deoxyribose nucleic acid (DNA). This molecule carries genetic codes from all proteins that make up the structural and functional components of life and is passed from generation to generation. Study of DNA molecule is important to know different aspects of life. DNA molecule controls activities of life which bears hydrogen, oxygen, carbon, nitrogen and phosphorus; cell is the fundamental unit of life.
Animals are united at all levels because of their evolutionary origin and shared forces that influence their history. Evolutionary processes are remarkable for their relative simplicity, yet they have some effects on life forms. Evolutionary processes have resulted in an estimated 4 to 30 million species of organisms living today. Out of these 1.4 million species have been described, many existed in the past and have become extinct.
They of organic evolution are the concept that population of organisms change over time.
Charles Darwin (1809 – 1892) described evidence for his theory in the origin of species by means of Natural selection in 1859. By 1900 most biologists were convinced that evolution takes place through natural selection evidences.
Evidences of Evolution:
A number of evidences in favour of evolution are available some of these are as follows:
(1) Biogeography: It is the study of geographical study of plants and animals. Biogeographers try to explain why organisms are distributed as they are. Biogeographic studies show that life forms in different parts of the world have distinctive evolutionary histories. One of the distribution patterns that biogeographers try to explain is how similar groups of organisms can live in places separated by seemingly impenetrable of most continents of the earth, yet they cannot cross wide open oceans. Similarities in morphology suggest common ancestry but similarly obvious differences result from millions of years of independent evolution. Geographers also try to explain why plants and animals separated by geographical barriers like ocean, sea, rivers, streams, mountains, deserts and forests etc are often very different inspite of similar environments e.g. animals living in Australia and Tasmania are very different from animals in any other part of the world. Major native herbivores of Australia and Tasmania are many species of Kangaroo. Tasmania wolf known as tiger now considered being extinct was predatory marsupial that was unlike any other large predator.
(2) Paleontology: It is based on study of fossil record, provides direct evidences for evolution. Fossils are the evidences of plants and animals that existed in the past have become incorporated into earth’s crust in the form of rocks or minerals. Paleontologists estimate that the earth is about 4.6 billion years old. They have also used the fossil record to describe the history of life on the earth.
(3) Comparative anatomy: A structure in one animal may resemble a structure in another animal because of common evolutionary origin. Structures or organs derived from common ancestry are called homologous organs and its study is known as homology. Homologous organs have same or similar origin and perform same functions e.g. vertebrate appendages have common arrangements of similar bones even though the function of appendages may vary. This indicates that vertebrates have evolved from common ancestor convergent evolution occurs when two unrelated organisms adapt to similar conditions e.g. wing of a bird and wing of an insect are both adapted for flight but they are not homologous. Being homologous these structures are analogous that is having similar function but dissimilar origin.
Organisms often retain structures that have lost their usefulness. These structures are poorly developed and are called vestigial structures e.g. boa constrictors have minute remnants of hind limbs bones left over from appendages of their reptilian ancestors. Such remnants of once useful structures are clear indications of evolution.
(4) Molecular biology: It has provided important information on evolutionary relationships. Structure and function are based on genetic blue print found in all living animals in the form of DNA molecule related animals have similar DNA derived from common ancestor. Because DNA carries the codes for proteins that make up each animal, related animals have similar proteins. Evolutionary theory has impressed biologist to believe with fundamental unity of all of biologists.

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