BIOLOGY FOR 9TH CLASS (UNIT # 2)============================================================THEORYQuestion: What are the necessary steps that biologists take to solve abiological problem?i)Recognition of biological problemii)Observationiii)Hypothesis formulationiv)Deductionv)Experimentationvi)Summarization of results (create tables, graphics etc)vii) Reporting the ResultsRecognition of biological problem:A biological problem is a question related to living organisms.Observation:Observations are made with the help of five senses. Observations may be bothqualitative and quantitative. Quantitative observations are considered moresuitable.Formulation of Hypothesis:The tentative explanation of the observations is called hypothesis. It may beconsidered as a proposition that might be true.Following are the characteristics of a good hypothesis: -i)It should be a general statementii)It should be a tentative ideaiii)It should agree with available observationsiv)It should be kept as simple as possiblev)It should be testable and potentially falsifiable.Deductions:Deductions are the logical consequences of hypothesisExperimentation:Biologists perform experiments to see if hypothesis is true or not. After experimentincorrect hypothesis are rejected and true ones are accepted.Summarization of Results:Biologists gather actual quantitative data from experiments. This data is thencompared statistically. This helps in drawing conclusion.Reporting the Results:============================================================BIOLOGY FOR 9TH CLASS (UNIT # 2)============================================================

Biologists publish their findings in scientific journals and books. Publishing of Resultsis an essential part of scientific method. It allows other people to verify the resultsor to apply the knowledge.>> Question: Give an example of solving biological problem keeping in

view the study of malaria.Introduction:In ancient times (2000 years ago), physician were familiar with malaria. Theydescribe it as a disease of chills and fevers with recurring attacks. Theyobserved that this disease was common in low, marshy areas. The word “Malaria”was derived from two Latin words:i)Mala means bad.ii)Aria means air.So, the meaning of malaria becomes bad air. Quinine from cinchona bark was aneffective remedy for malaria.Observations:• In1878, a French army physician Laveran began to search for the cause ofmalaria.• He observed the blood of malarial patients under microscope and found sometiny creatures in it.• His discovery was not believed by other biologists.• Two year later same results were drawn by another physician and three yearslater same observations were found third time.• The organism was given the name Plasmodium.By that time, there were four major observations about malaria.i)Malaria and marshy areas have some relationii)Quinine is an effective drug for treating malariaiii)Drinking the water of marshes does not cause malaria.iv)Plasmodium is seen in the blood of malarial patients.Hypothesis:Regarding malaria the hypothesis made was: “Plasmodium is the cause of malaria”Deduction:Regarding malaria deduction was made from above hypothesis is:“If plasmodium is the cause of malaria, then all person ill with malaria shouldhave plasmodium in their blood.”Experiment:• Then blood of 100 malarial patients was examined under microscope.• The results showed that all malarial patients had plasmodium in their blood.While 7 out of 100 healthy persons also had plasmodium in their blood.============================================================BIOLOGY FOR 9TH CLASS (UNIT # 2)============================================================• In the healthy people plasmodium was in incubation period(The period

between the entry of parasite in host and the appearance of symptoms.)• The result was convincing and proved the hypothesis.How Plasmodium enter in Man:Now next step was that how plasmodium gets into the blood of man? In this regardbiologists were having following observations:i)Malaria is associated with marshesii)Drinking water of marshes does not cause malaria.

In this regard, A.F.A King made his observations in 1883. His observations were:i)People who slept outdoors in open spaces suffered more from malaria thanthose who slept indoors.ii)People who slept under mosquito nets did not suffer from malaria.iii)Person who slept near smoky fire also did not suffer form malaria.On the basis of these observations King suggested a hypothesis:“Mosquitoes transmit Plasmodium and so are involved in the spread of malaria.”For this hypothesis, following deductions were made:i)“Plasmodium should be present in mosquitoes”ii)“A mosquito can get Plasmodium by biting a malarial patient”Experiment of Ronald Ross:To test these deductions Ronald Ross, a British army physician performed hisexperiments in 1880’s in India.• He allowed a female Anopheles mosquito to bite a malarial patient. He killed themosquito some days later and found Plasmodium multiplying in mosquito’sstomach.• Next step was to allow the infected mosquito to bite a healthy person. But thiswas a risky work as that healthy person can be suffered from malaria. So heselected sparrows for his experiment.• He allowed a female Culex mosquito to bite a malarial sparrow.• Then he allowed those mosquitoes to bite a healthy sparrow.• The healthy sparrow also suffered from malaria.• In this way he proves that plasmodium is the real cause of malaria and theyare transmitted by mosquitoes.In 1898, an Italian biologists performed same experiments on human beings andfind the same results. This confirmed that mosquitoes are involved in the spread ofthis disease.Theory:When a hypothesis has been proved by consistent results it becomes a theory.Scientific Principal or LAW:============================================================BIOLOGY FOR 9TH CLASS (UNIT # 2)============================================================When a theory can explain many natural phenomena and consistently supported

by experiments, and also universally accepted by scientists it becomes ascientific principal or Law.Question: Why female mosquito is involved in spreading malaria?Female mosquitoes need blood of mammals or birds for the maturation of their eggs.Question: Which mosquito is involved in spreading the dengue fever?Aedes mosquitoQuestion: Define and describe the terms data organization and dataanalysis in the biologicalmethod?Data Organization:• Scientists collect and organize data to formulate and test the hypothesis.• It is very important to describe data collection methods before experiments as itensures the quality of experiment.• Data is organized in different formats like graphics, tables, flow charts, maps anddiagrams.Data Analysis:

• The process of data analysis prove or disprove a hypothesis.• It is done through statistical methods. i.e. ratio and proportion• Data analysis is proved very fruitful in publishing the reports.Question: Quantitative observations are better in biological method. How?Quantitative observations are considered more accurate because the former areinvariable and measurable and can be recorded in terms of numbers.Question: Justify mathematics as an integral part of the scientific process?Major biological problems in which knowledge of mathematics is used include genefinding, protein structure, and protein-protein interactions etc. Bioinformatics refersto the computational and statistical techniques for the analysis of biological data.=*=*=*=*=

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