Q#1: What is the biological method? Discuss steps involved in the biological method.
Biological method
The scientific method by which biological problems are solved is called the biological method.
Steps involved in biological method
Biology being a natural science follows the following steps of the scientific method to solve biological problems.
1. Recognition of the biological problem
It begins with the information of a question relating to the problem. For example, what are the risk factors for heart failure? or what are the causes of lung cancer?
2. Making an observation
The study of something with the naked eye or with the help of some instrument is called observation. Observations help scientists in finding a solution. For this purpose, they recall their old observations and also study previous research on the same problem.
Observations are of two types
a. Qualitative observations: The observations that can be described but not measured are called qualitative observations. For example, Colour, taste, smell, texture, etc.
b. Quantitative observations: The observations that can be described numerically are called
quantitative observations. For example, height, temperature, pressure,
cost, length, etc.
3. Formulate a Hypothesis
The untested explanation given by a scientist may be true or false and is called a hypothesis. The accuracy of the hypothesis can be tested through experiments. The hypothesis is a possible answer to a biological problem.
Characteristics of a good hypothesis
- It should be based upon the observations of biologists.
- It is a proposed statement to answer the questions.
- It should be testable through experiments.
- It may be accepted or disprove after experimentation.
5. Deduction
A deduction is a logical result of a hypothesis. It involves an ‘if’ and ‘then’ statement. A deduction is done through reasoning.
6. Reasoning
The process of thinking about something to draw a conclusion is called reasoning. There are two types of reasoning
I: Deductive reasoning
The type of reasoning which moves from general to specific is called deductive reasoning.
For example, if we argue that all birds have wings and a pigeon has wings and it is a bird so we conclude that all birds have wings.
ii: Inductive reasoning
The type of reasoning which moves from specific to general is called inductive reasoning.
For example, if we argue that all pigeons have wings and it is a bird so we conclude that all birds have wings.
6. Experiment
In order to prove whether the given statement is true or false experiments are conducted. If the hypothesis is made true it is accepted otherwise it is rejected. For this purpose, two groups are made
a. Experimental group Patients (people under observation) belong to the experimental group.
b. Control group Healthy persons belong to the control group.
If the results of experiments do not support any hypothesis then new hypotheses are developed and tested.
7. Conclusion and reporting drawn through data
During experiments, the scientists collect data. This data is analyzed to come to a satisfactory conclusion. Scientists publish their conclusion in the form of research articles.
8. Theory
When more research is carried out on a hypothesis and all the available evidence favour it, then it becomes a theory.
9. Scientific laws/Principles
A statement of fact that can explain many natural phenomena and is fully supported by experiments and also universally accepted by scientists then it becomes law or principle.
Q#2: Explain how biologists use scientific methods to solve the mysteries of addressing the malarial problem.
Malaria
Malaria is the combination of two Italian words ‘mala means bad’ and ‘aria means air’. It is an infectious disease spread through the bite of female Anopheles mosquitoes. Malaria is a biological problem and so can be solved by steps of biological method as given below.
1. Observation
Following are some observations made by scientists about malaria.
- Patients of malaria experience recurring attacks of chills and fever.
- People living in low-marshy areas are more affected by malaria.
- Drinking marshes water does not develop malaria.
Laveran observations
Laveran, a French army surgeon, observed small tiny creatures in the blood of malarial patients. These tiny creatures were named ‘Plasmodium’.
2. Hypothesis and deduction
Different scientists formulated a different hypothesis to solve the malarial problem. Such as
Hypothesis-I
“Plasmodium is the cause of malaria”
This hypothesis is based on the observations of Laveran.
Hypothesis-II
“Mosquitoes are involved in the spread of malaria”
This hypothesis is based on the observations of A.F.A King (an American scientist).
Hypothesis-III
“If mosquitoes are involved in the spread of malaria, then it must have plasmodium in its blood after it had bitten a malarial patient”
This hypothesis is based on the observations of Ronal Ross (a British army physician).
3. Deduction
On the basis of these observations, biologists made a deduction that “if plasmodium is the cause of malaria, then all the malarial patients should have plasmodium in their blood”
4. Experiments
To test the hypothesis that “plasmodium is the cause of malaria”, biologists carried out the following experiments on the experimental group and control group.
a) Biologists examined the blood of several malarial patients (experimental group) under a microscope.
b) They also examined the blood of several healthy persons (control group) under a microscope.
5. Results
It was observed that all the malarial patients had plasmodium in their blood while healthy persons were free from plasmodium. From these results, it was confirmed that “plasmodium is the cause of malaria”. So it was taken as the solution to a biological problem.
Q#3: Explain the biological problem “How is plasmodium transmitted to human beings?”
How is plasmodium transmitted to human beings?
The transmission of plasmodium to human beings is a biological problem and can be solved by following the steps of the biological method.
i. Observation
Following are some observations made by scientists about malaria.
- Patients of malaria experience recurring attacks of chills and fever.
- People living in low-marshy areas are more affected by malaria.
- Drinking marshes water does not develop malaria.
In 1883, A.F.A King listed 20 more observations about malaria, some of which are
- People who slept in open places suffered more from malaria than those who slept indoors.
- Less number of people suffered from malaria who used to sleep in smoking places.
- People who used mosquito nets suffered less than the ones who did not use mosquito nets.
ii. Hypothesis and deduction
A.F.A King, on the basis of his observations, suggested a hypothesis that “mosquito transmit plasmodium”. The statement of this hypothesis leads him to the deduction that “if mosquitoes transmit plasmodium, then plasmodium should be present in mosquitoes”.
iii. Experiment and result
A British army physician, Ronald Ross, performed an experiment to test the deduction made by A.F.A King. For this, he was awarded the Noble prize. He choose two types of mosquitoes i.e. culex and anopheles mosquitoes and experimented with them on humans and sparrows.
First, he let both types suck the blood of malarial patients (experimental group) and then bite the healthy sparrows (control group). Culex caused malaria in sparrows while female anopheles mosquitoes caused malaria in human beings. Plasmodium was found first in the stomach wall of mosquitoes and later on in salivary glands.
iv. Result
Ronal Ross, on the basis on his experiment, confirmed the hypothesis and deduction of A.F.A King.
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