Notes

Science is a systemized knowledge derived from observations and experiments carried out to determine the principles of how nature operates.

Man has always been a biologist. He has to be a biologist to live. Early, in history, he was a hunter of animals and a gatherer of fruits, seeds, roots, etc. The more he knew about 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 scientific methods by which biological problems are solved are termed biological methods. It comprises the steps a biologist adopts to solve a biological problem.

Significance of biological method:

The biological method has played an instrumental part in biological research for almost 500 years. From Galileo’s experiment back in the 1590s till current research, the biological method has contributed to the creation of vaccines and advancements in medicine and technology. The biological method also ensures the quality of data for public use.

          Solving a Biological Problem:

In solving a biological problem, a biologist takes the following steps:

1. Recognition of the biological problem
2. Observations
3. Hypothesis formulations
4. Deductions
5. Experimentation
6. Summarization of results (creates tables, graphics, etc)
7. Reporting the results

• Recognition of a biological Problem:

Biologists go for adopting the biological methods when they encounter some biological problem. A biological problem is a query that is either asked by someone or comes into a biologist’s mind by himself.

• Observations:

As the first step in solving a biological problem, the biologists recall/her

previous observations or make new ones. Observations are made with the 5 senses vision, hearing, smell, taste, and touch.

       Types of Observations:

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:

Note:

Observations also include reading and studying what others have done in the past because scientific knowledge is ever-growing.

• Construction and Formulation of Hypothesis:

The tentative explanation of observations is called a hypothesis. It may be defined as a proposition that might be true.

Characteristics of Hypothesis:

A Hypothesis should have the following characteristics:

1. It should be a general statement.
2. It should be a tentative idea.
3. It should agree with available observations.
4. It should be kept as simple as possible.
5. It should be testable and potentially falsifiable. In other words, there should be a way to show the hypothesis is false; a way to disapprove of the hypothesis.

Conditions for Hypothesis:

A great deal of creative and careful thinking is necessary for the construction of a hypothesis. Biologists use reasoning to formulate a hypothesis.

Types of Reasoning: 

The reasoning may be of two types.

• Inductive Reasoning:

In inductive reasoning, specific observations are used to draw general hypotheses. For Example; I observed cells in x, y, and z organisms therefore all organisms have cells.

• Deductive reasoning:

Deductive reasoning flows from general to specific. From general observations, a biologist conducts specific hypotheses. For Example; If all organisms have cells and humans are organisms, then humans should have cells.

4. Deductions:

The biologists draw deductions from hypotheses. Deductions are the logical consequences of Hypotheses. Deductions are also drawn through inductive and deductive reasoning. Generally, in a biological method, if the particular hypothesis is true then one should expect a certain result. This involves the use of “if-then” logic.

5. Experimentation:

In most basic steps of biological methods, biologists perform experiments to see if the hypothesis is true. An experiment involves an alternative hypothesis. A successful experiment is that which demonstrates one or more alternative hypotheses as incorrect (inconsistent with experimental and observational results). The incorrect hypothesis is rejected and those which prove consistent with experimental results are accepted. An expected hypothesis needs to be valid and useful. It makes further predictions that provide an important way to further test its validity.

6. Summarization of results:

The biologists gather actual, quantitative data from experiments. Data for each group is then averaged and compared statistically. To conclude the biologists also use statistical analysis.

7. Reporting the results:

Biologists publish their writings in scientific journals and books, in talks in international seminars and meetings, and in seminars at colleges and universities. Publishing of results is an essential part of scientific methods. It allows other people to verify the results or apply the knowledge to solve other problems.

In science, when experimenting, it must be a controlled experiment. The Scientists must contrast an “experimental group” with a “control group”. The two groups are treated exactly alike except for one variable being tested.

For example, in an experiment to check the necessity of CO₂ for photosynthesis one can contrast the control group (a plant with freely available carbon dioxide) with an experimental group (a plant with no available carbon dioxide). The necessity of carbon dioxide would be proved when photosynthesis occurs in the control group and doesn’t occur in the experimental group.

Darwin not only took notes during his voyage but he also reads the work of other naturalists to form his theory of evaluation.

Biologists can’t usually check every situation where a hypothesis might apply. Let’s consider a hypothesis, “all plant cells have a nucleus”. Biologists can’t examine every living plant that has ever lived to see if the hypothesis is false. Instead, biologists generate a deduction: “If I examine cells from a blade of grass then each one will have a nucleus”.

Quinine was the only effective remedy for malaria from the 17^th to 20^th centuries.

Study of malaria - an example of biological method:

In the last part of the nineteenth century, many different causes of malaria were suggested.

Observations about malaria:

By that time there were 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. We know that a scientist uses whatever information and observation he has and makes one or more hypotheses.

Hypothesis about malaria:

The hypothesis made in this case was:

"Plasmodium is the cause of malaria."

The scientist does not know whether his hypothesis is true or not, but he accepts it may be true and makes deductions. One of the deductions from the above hypothesis was: "If Plasmodium is the cause of malaria, then all people ill with malaria should have Plasmodium in their blood."

An experiment about malaria:

The next step was to test the deduction through experiments which were designed "Blood of 100 malarial patients was examined under a microscope. To have a control group, the blood of 100 healthy persons was also examined under a microscope."

Results about malaria:

The results of the experiments showed that almost all malarial patients had Plasmodium in their blood while 07 out of 100 healthy persons also 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.

Female mosquitoes need the blood of mammals and birds for the maturation of their eggs.

When a female mosquito pierces the skin with her mouthparts, she injects a small amount of saliva into the wounds before drawing blood. The saliva prevents the blood from clotting in her food canal.

The welts that appear after the mosquito leaves are not a reaction to the wound but an allergic reaction to the saliva. In most cases, the itching sensation and swellings subside within several hours.

Blood of healthy Persons.

The hypothesis that stands the test of time (often tested and never rejected) are called theories. A theory is supported by a great deal of evidence.

Productive theory keeps on suggesting new hypotheses and so testing goes on. Many biologists take it as a challenge and exert greater efforts to disapprove of the theory.

Law and Principle:

If a theory survives such a doubtful approach and continues to be supported by experimental evidence, it becomes a law or principle. A scientific law is a uniform or constant fact of nature. It is an irrefutable theory. Examples of the biological theory are Hardy-Weinberg's law and Mendel’s law of inheritance.

Data:

Data can be defined as a single piece of information such as names, dates, and values made from observation and experimentation.

Principles of ratio and proportion:

Proportion means to join two equal ratios by the sign of equality (=). For example, a: b = c: d is a proportion between the two ratios. This proportion may also be expressed as a: b: c: d.

In every proportion of two ratios, there are four terms i.e. the first and fourth terms are called extremes, and the second and third are called means. So, in the above proportion 'a' and 'd' are extremes while 'b' and 'care means. The basic rule used to solve problems through ratios and proportion is that the product of the extremes is equal to the product of means. When three values in a proportion are known, the fourth one (X) can be calculated by using this rule.

For example, a biologist can calculate how many birds would get malaria when he allows infected mosquitoes to bite 100 healthy sparrows. In the previous experiment he noted that when he allowed mosquitoes to bite 20 sparrows, 14 out of them got malaria. Now he uses the proportion rule

Data Organization:

1. To formulate and then test the hypothesis scientists collect and organize data. Through the use of variables and controls results can be determined. Variables are those factors being tested in an experiment and are usually compared to a control. A control is a known measure to which scientists can compare their results.
2. Before experimenting, scientists need to describe data collection methods. It ensures the quality of the Attention must be paid to ensure the data collection methods are kept balanced.
3. Data is organized in different formats like graphics, tables, flow charts, maps, and diagrams.

Data analysis:

Data analysis is necessary to prove or disapprove a hypothesis by experimentation. The methods involved in testing/analyzing the data are also important since an experiment is repeated by others to ensure the quality of results. Depending on the type of data the biological problem, this might include the application of statistical methods i.e. ratio and proportion. When a relationship between two numbers e.g. ‘a’ and ‘b’ is expressed in terms of the quotient (a/b), such a relation is a ratio of one number to the other. A ratio may be expressed by putting a division (+) or colon (:) between two numbers. For Example, the ratio between 50 malarial patients and 150 normal persons is 1:3.

Mathematics as an integral part of the scientific process:

The biological method also involves the use of applied mathematics to solve biological problems. Major biological problems in which knowledge of mathematics is used include gene finding protein structure, protein-protein interactions, and the modeling of evolution.

Bioinformatics:

Bioinformatics refers to the use of algorithms and computational and statistical techniques for the analysis of biological data.

Computational biology:

Computational biology refers to a hypothesis-driven investigation of a specific biological problem using computers.