solving a biological problem |chapter 2 (part 1)|class 9 biology| FBISE& RBISE
experiments are carried out to determine the principles about how nature operates. Scientists like chemists, biologists and physicists use the same scientific method to make and test new theories.
In this chapter, we will study the steps of biological method. We will study malaria as an example
to understand the steps in detail.
2.1 Biological Method
Questions about living things have provided problems that man has investigated to aid his own
survival and to satisfy his desire to know. The scientific method in which biological problems are
solved, is termed as biological method. It comprises the steps a biologist adopts in order to solve a
biological problem. Biological method has played an important part in scientific research for almost
500 years. From Galileo’s experiment (in the 1590s) to current research, the biological method has contributed to the advancements in medicine, ecology, technology etc. Biological method also ensures the quality of data for public use
2.1.1 Biological problem, hypothesis, deductions and experiments
In biology (like other sciences), new things are being discovered and long-held theories are being
modified or replaced with better ones as more data/knowledge is accumulated. This happens when
biologists recognize some biological problem and go for its solution. In solving a biological problem,
biologist takes following steps;
• Recognition of biological problem
• Observations
• Hypothesis formulation
• Deduction
• Experimentation
• Summarization of results (create tables, graphics etc)
• Reporting the results
Man has always been a biologist. He had to be a biologist in order to live. Early in history, he was a
hunter of animals and a gatherer of fruits, seeds, roots etc. The more he knew about animals and their
habitat, the more successful hunter he was. The more he knew about plants, the better he distinguished
between edible and non-edible plants.
The details of these steps are as under:
1. Recognition of the Biological Problem
Biologists go for adopting biological method when they encounter some biological problem. A
biological problem is a question related to living organisms that is either asked by some one or
comes in biologist’s mind by himself.
2. Observations
As the first step in solving a biological problem, biologist recalls his/her previous observations or
makes new ones. Observations are made with five senses of vision, hearing, smell, taste and touch.
Observations may be both qualitative and quantitative. Quantitative observations are considered
more accurate than qualitative ones because the former are invariable and measurable and can
be recorded in terms of numbers. Examples of qualitative and quantitative observations are given
below.
Qualitative observations Quantitative observations
• The freezing point of water is colder than The freezing point of water 0 oC and the
the boiling point. boiling point is 100 oC.
• A liter of water is heavier than a liter of
ethanol. A liter of water weighs 1000 grams and a liter
of ethanol weighs 789 grams.
Observations also include reading and studying what others have done in the past because
scientific knowledge is ever-growing.
Biologists can’t usually check every situation where a hypothesis might apply. Let’s consider a
hypothesis:
“All plant cells have a nucleus”. Biologist cannot examine every living plant and every plant that
has ever lived to see if this hypothesis is false. Instead, biologists generate deduction using
reasoning. From the above hypothesis, a biologist can make the following deduction: “If examine
cells from a blade of grass, then each one will have a nucleus”.
3. Formulation of Hypotheses
Observations do not become scientific observations until they are organized and related to a
question.Biologist organizes his/her and others’ observations into data form and constructs a
statement that may prove to be the answer of the biological problem under study. This tentative
explanation of observations is called a hypothesis. It may be defined as a proposition that might be
true. A hypothesis should have the following characteristics:
• It should be a general statement.
• It should be a tentative idea.
• It should agree with available observations.
• It should be kept as simple as possible.
• It should be testable and potentially falsifiable. In other words, there should be a way to show
the hypothesis is false; a way to disprove the hypothesis.
A great deal of careful and creative thinking is necessary for the formulation of a hypothesis.
Biologists use reasoning to formulate a hypothesis.
4. Deductions
In the next step, biologist draws deductions from hypotheses. Deductions are the logical
consequences of hypotheses. For this purpose, a hypothesis is taken as true and expected results
(deductions) are drawn from it.
Generally in biological method, if a particular hypothesis is true then one should expect (deduction)
a certain result. This involves the use of “if-then” logic.
5. Experimentation
The most basic step of biological method is experimentation. Biologist performs experiments to
see if hypotheses are true or not. The deductions, which are drawn from hypotheses, are subjected
to rigorous testing. Through experimentations, biologist learns which hypothesis is correct.
The incorrect hypotheses are rejected and the one which proves correct is accepted. An accepted
hypothesis makes further predictions that provide an important way to further test its validity.
6. Summarization of results
Biologist gathers actual, quantitative data from experiments. Data for each of the groups are then
averaged and compared statistically. To draw conclusions, biologist also uses statistical analysis.
7. Reporting the results
Biologists publish their findings in scientific journals and books, in talks at national and international
meetings and in seminars at colleges and universities. Publishing of results is an essential part of
scientific method. It allows other people to verify the results or apply the knowledge to solve other
problems.
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