9th Class Chapter 2 Biology Long Questions

Explain biological method with an example of malaria.

Observations about Malaria. (1) Disease of chills and fever In ancient times, physicians were familiar with this disease. They described it as a disease of chills and fever with recurring attacks. They observed that the disease was more common among people living in low marshy areas. (2) Association of malaria with marshy places It was thought that the stagnant water of marshes poisoned the air and as a result of breathing in this "bad air", people got malaria. This belief lead to the name of disease "Malaria". (3) Meaning of malaria A combination of two Italian words. "The Italian word for "bad" is mala and "air" is aria". (4) Marshes and Malaria Some volunteers drank the stagnant water from the mai6hes. They did not develop malaria. (5) Treatment of malaria by using cinchona bark In 17th century, many plants from America were sent back to Europe to be used as medicines. The bark of a tree known as quina-quina was very suitable for curing fevers. Some dishonest merchants began to substitute the bark of another tree; "cinchona" which closely resembled quina-quina. This dishonesty proved much valuable for mankind. Cinchona bark was found to be excellent for treating malaria. Cinchona bark contains quinine that is effective in treating the disease. (6) Work of Laveran In 1878, a French army physician Lavern began to search for the cause of malaria. He took a small amount of blood from a malarial patient and examined it under microscope. He noticed some tiny living creatures. The organism was given a name "Plasmodium". (7) Four major observations about malaria 1. Malaria and marshy areas have some relation. 2. Quinine is an effective drug for treating malaria. 3. Drinking the water of marshes does not cause malaria. 4. Plasmodium is seen in the blood of malarial patients. Hypothesis The hypothesis made regarding malaria was "Plasmodium is the cause of malaria". Deduction Following deduction is drawn from the above mentioned hypothesis. "If the Plasmodium is the cause of malaria then all persons ill with malaria should have Plasmodium in their blood". Experiments The next step was to test the deduction through experiments which were designed as: (i) Experimental Group Blood of 100 malarial patients was examined under microscope. (ii) Control Group Blood of 100 healthy persons was also examined under microscope. Results The results of the experiments showed that almost all malarial patients had Plasmodium in their blood while 7 out of 100 healthy persons had plasmodium in their blood. Now we know that Plasmodium in the blood of healthy people was in incubation period i.e. the period between the entry of Parasite in host and appearance of symptoms. The results were quite convincing and proved that the hypothesis "Plasmodium is the cause of malaria" was true.

How Plasmodium gets into human body?

It was the next biological problem. The biologists want to learn how plasmodium gets into the blood of man (i) Observations . Biologists had following observations: v Malaria is associated with marshes + Drinking water of marshes does not cause malaria These observations show that plasmodium was not present in the marsh water. But it must be carried by something. That thing comes to marsh water. (ii) Work of A.F.A.King (Lahore board 2012 G 1) In 1883, a physician A.F.A. King listed 20 observations some important observations of king were: (iii)Observations of A.F.A King v People who slept outdoors were more likely to get malaria than those who slept indoors. + People who slept under fine nets were less likely to get malaria than those who did not use such nets v An individual who slept near smoky fire usually did not get malaria. (iv)King's Hypothesis "Mosquitoes are involved in the spread of malaria". (v) Deductions Following deductions were made considering the hypothesis as true i.e; If mosquitoes are involved in the spread of malaria then; Deduction 1 "Plasmodium should be present in mosquitoes". Deduction 2 "A mosquito can get plasmodium by biting a malarial patient." (vi) Experiments of Ronald Ross (Lahore board 2012 G I) Introduction In order to test the above deductions, Ronald Ross, a British army physician working in India in 1880's, performed important experiments. Experiment No. 1 Ross allowed a female Anopheles mosquito to bite a malarial patient. He killed the mosquito some days later and found plasmodium multiplying in mosquito's stomach. The next logical experiment was to allow an infected mosquito to bite a healthy person. If the hypothesis was true, the healthy person would have got malaria but scientists avoid using human beings for experiments. 'Experiment No2. Ross used sparrows and redesigned his experiments. He allowed a female culex mosquito to bite on the sparrows suffering from malaria. Some of the mosquitoes were killed and studied at various times. In each mosquito, Ross found that plasmodium multiplied in the wall of mosquito's stomach and then moved into the mosquito's salivary glands. 'Experiment No. 3 Ross kept some mosquitoes alive in the Second experiment and allowed them to Bite healthy sparrows. Ross found that Saliva of the infected mosquito Containe Plasmodium and these entered the - Sparrow’s blood. When he examined the Anopheles blood of these previously healthy sparrows, he found many plasmodium in it. Conclusion Ross concluded that similar relationship is found in mosquito and plasmodium. (vii) Experiments on Man In the end, the hypothesis that "mosquitoes transmit plasmodium and so are involved in the spread of malaria" was tested by direct experimentation on human beings. In 1898, some Italian Biologists allowed an Anopheles mosquito to bite a malarial patient. The mosquito was kept for a few days and then it was allowed to bite a healthy man. This person became ill with malaria. In this way, it was confirmed that mosquitoes transmit plasmodium and so are involved in the spread of malaria. (viii) Theory: The hypothesis that stand the test of time (often tested and never rejected) is called theory. A theory is supported by a great deal of evidence. (ix) Law and Principle: If a theory survives a doubtful approach and continues to be supported by experimental evidence, t becomes a law or principle. A scientific law is a uniform or constant fact of nature. It is an irrefutable theory. The examples of biological laws are Hardy Weinberg law and Mendel's law of inheritance.

Explain the importance of data organization and data analysis in biological method.

Describe observations of A.F.A King said experiments of Ronald rose to solve malarial problem.

In 1883 a physician .A.F.A king listed 20 observation some important observation some important observation of king were.

Define <gwmw class="ginger-module-highlighter-mistake-type-3" id="gwmw-15863640737031693964890">biological method</gwmw>. Describe the theory and <gwmw class="ginger-module-highlighter-mistake-type-3" id="gwmw-15863641407344007208257">law stage</gwmw> of biological method.

The scientific method in which biological problems are solved is termed as biological method

Write experiments of Ronald Ross?

Ronald Ross, a british army physician working in india in 1889's pergormed important experiments.

Write mathematics as an integral of data organization and analysisin biological method.

Biologist method also involves the use of applied mathematics to solve biological problems. Major biological probelms.In which knowledge of mathematics is used to include gene finding protein stucture and protein- protein interactionsetc. Bioinfomatics refers to the computational and statistical techniques for the analysis of biological data

Explainimportance of data organization and data analysis in biological method.

In order to formulate and then to test hypothesis scientist called and organize data prior to conducting an experimentfor a scientist to describedata collection method.

Write four steps of solving biologicalproblems.

Biologist takes following steps.