science and Scientific method
Science: word science is derived from scientia means knowledge.
Science is the systemized knowledge derived from observations and experiments.
The knowledge that gives understanding about this world and how it works is called science.
The systemized knowledge obtained by observations and experiments is called science.
Scientific method: A way to gather information and answer questions in science is called scientific method. “OR” A method used by scientists to solve scientific problems is called scientific method. “OR” The scientific method is a process for experimentation that is use to explore observations and answer questions.
Biological method: The scientific method in which biological problems are solved is called biological method. OR “A method used by biologists to solve biological problems is called biological method.
Importance of Biological method: Biological method is the best to obtain reliable knowledge about biology. It comprises all the steps a biologist adopt in order to solve a biological problem.biological method contribute to advancements in all biology related fields like medicine, ecology, biotechnology, etc. Biological method also ensures the quality of data for public use.
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. The problem faced by a biologist during biological experiments , study or research is called biological problem.
Steps of a biological method “OR” Steps to solve a biological problem: Following are the basic steps a biologist can adopt during his research work or during a biological method.
1• Recognition of biological problem
3• Hypothesis formulation
6• Summarization of results (create tables, graphics etc)
7• 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.
Darwin not only observed and took notes during his voyage, but he also read the works of other naturalists to form his theory of Evolution.
1• Recognition of 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: The act of noticing something is called observation. 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:Observations that are measureable are called Quantitative observations. E.g: size of the plants, number of petals, etc.
- Qualitative observations: Observations that are descriptive and non measureable are called qualitative observations. E.g, color of flower, taste , etc.
• The freezing point of water is colder than the boiling point.
• A liter of water is heavier than a liter of ethanol.
• The freezing point of water 0 oC and the boiling point is 100 0C0.
• A liter of water weighs 1000 grams and a liter of ethanol weighs 789 grams.
- Formulation of Hypotheses: Tentative explanation of observations is called a hypothesis. A hypothesis may be a prepositions that might be true. A scientist is seeking. His hypothesis may be true or false. But he accepts it to be true. A hypothesis is a possible answer to a biological(scientific) problem(question). A hypothesis is an educated guess or statement made by biologist about a certain process on the basis of available information.
- Characteristics of a good hypothesis: 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.
Logical conclusion drawn from hypothesis are called deductions. At this step hypothesis is taken as true and expected results (deductions) are drawn from it. Deductions involves the use of “if-then” logic.
Regarding malaria deduction was made:
“If plasmodium is the cause of malaria, then all person ill with malaria should
have plasmodium in their blood.”
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”.
- Experimentation: The act of Performing experiments is called experimentation. It is the most important step in biological method. Biologist performs experiments to see if hypotheses are true or not. The incorrect hypotheses are rejected and the one which proves correct is accepted.
What is “Control” in experiments?
In science when doing the experiment, it must be a controlled experiment. The scientist must contrast an “experimental group” with a “control group”. The two groups are treated exactly alike except for the one variable being tested. For example, in an experiment to test the necessity of carbon dioxide for photosynthesis, one can contrast the control group (a plant with freely available carbon dioxide) with an experimental group (a plant with no carbon dioxide available). The necessity of carbon dioxide will be proved when photosynthesis occurs in the control group and does not occur in the experimental group.
- 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 if the data is quantitative type.
- 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.
Steps involved in biological method taking malaria as an example:
In ancient times (2000 years ago), physician were familiar with malaria. They describe it as a disease of chills and fevers with recurring attacks. They observed 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 an effective remedy for malaria.
- In 1878, a French army physician Laveranbegan to search for the cause of malaria.
- He observed the blood of malarial patients under microscope and found some tiny creatures in it.
- His discovery was not believed by other biologists.
- Two year later same results were drawn by another physician and three years later 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 relation
- ii) Quinine is an effective drug for treating malaria
iii) Drinking the water of marshes does not cause malaria.
- iv) Plasmodium is seen in the blood of malarial patients.
Regarding malaria the hypothesis made was: “Plasmodium is the cause of malaria”
Regarding malaria deduction was made from above hypothesis is:
“If plasmodium is the cause of malaria, then all person ill with malaria should have plasmodium in their blood.”
- 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.
- In the healthy people plasmodium was in incubation 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 regard biologists were having following observations:
- i) Malaria is associated with marshes.
- ii) 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 than those 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 his experiments in 1880’s in India.
- He 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.
- Next step was to allow the infected mosquito to bite a healthy person. But this was a risky work as that healthy person can be suffered from malaria. So he selected 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 they are transmitted by mosquitoes.
In 1898, an Italian biologists performed same experiments on human beings and find the same results. This confirmed that mosquitoes are involved in the spread of this disease.
Theory: When a hypothesis is given a repeated exposure to experimentation and is not falsified, then it is called theory.
When a hypothesis has been proved by consistent results it becomes a theory. The hypotheses that stand the test of time (often tested and never rejected), are called theories. A theory is supported by a great deal of evidence.
Scientific Principal or LAW:
When a theory can explain many natural phenomena and consistently supported by experiments, and also universally accepted by scientists it becomes a scientific principal or Law.
Malaria has killed more people than any other disease. The account of malaria is an example of a biological problem and of how such problems are solved.
In fact quinine was the only effective remedy for malaria from the 17th to the 20th century.
When a female mosquito pierces the skin with her mouth parts, she injects a small amount of saliva into the wound before drawing blood. The saliva prevents the blood from clotting in her food canal.
The welts that appear after the mosquito leaves is 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.
Data organizations and data analysis
DATA : Data can be defined as the information such as names, dates or values made from observations and experimentation. “OR” Recorded observations is called data. “OR” Collection of facts and figures is called data.
In order to formulate and then to test hypotheses, scientists collect and organize data. Prior to conducting an experiment, it is very important for a scientist to describe data collection methods. It ensures the quality of experiment. Data is organized in different formats like graphics, tables, flow charts, maps and diagrams.
Data analysis is necessary to prove or disprove a hypothesis by experimentation. It is done through the application of statistical methods i.e. ratio and proportion.
Ratio: When a relation between two numbers e.g. ‘a’ and ‘b’ is expressed in terms of quotient (a/b), it is called the ratio of one number to the other. Ratio may be expressed by putting a division (÷) or colon (:) mark between the two numbers. For example the ratio between 50 malarial patients and 150 normal persons is 1:3.
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. When three values in a proportion are known, the fourth one (X) can be calculated.