NATURE OF SCIENCE2013 2014

Developments in biology have many impacts on every aspect of human life.

The major aim of studies in biology and technology is to find solutions for various environmental and health problems.

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Objectives• Recognize the role biology plays in current events and use theprocess of scientific reasoning to investigate scientific problems.• Being scientifically literate individuals in order to have ability totake part in science discussions and have ability to evaluate them• Understanding nature of science, scientific process and history ofbiology• Being aware of the advantages and disadvantages of modernscientific developments and applications that individuals comeacross in their daily life• Search for careers in biology for effective future decisions• Explain differences between living and non-living organisms• Determine the common proper ties of living organisms

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What is science?

• Science is a method of obtaining knowledge about nature. The word ‘’science’’ is derived from a Latin verb meaning ‘’to know’’

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Who is scientist?

• Scentist is a person who deals with science.A scientist must be:1. Logical2. Objective3. Open minded or not dogmatic4. Curious and suspicious

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Scientific method: The scientific method is a mean of gathering information and testing ideas.It is the way a scientist tries to find answer to his or her questions about nature.

The steps involved in scientific method are simple and make common sense to everyone. These steps are as follows:

1.Definition of the problem2.Collecting information about the problem and forming

hypothesis, Making predictions 3. Setting up controlled experiments based on predictions4.Evaluating the results of observations and experiments.5.Drawing a conclusion6.Theory and law

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1. Definition of the problem2013 2014

2. Collecting information about the problem and forming a hypothesis.

• Hypothesis is the possible answer to a question about nature ,based on observations and knowledge of the scientist.

A good hypothesis:a)explains all the available datab)provides predictions to new facts.c)must be tested by experiments

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After setting up a hypothesis, predictions must be made if the hypothesis works well. A good prediction shows a logical linkage between cause and result that are expressed by if and then.

• If.......................(dependent variable) is related to .........................(independent variable)then

..................................(explanation)Ex:Coffee may stunt your growth.If growth is related to drinking coffee then someone

who drinks a lot of coffee will be short.

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• Activity hypothesis if then

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3. Setting up controlled experiments based on predictions

• The scientific testing of a hypothesis is called experimentation.

• An experiment generally includes observations. Observation is examining an event for a purpose .

• Two types of observations:

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• 1. Qualitative observations• If only the sense organs are used in the

observation ,it is called a qualitative observation.

• In a qualitative observation ,the answer the questions beginning with ‘’what’’ and ‘’how’’ are looked for. It is not scientific.

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• 2. Quantitative observations• If measuring devices like meter, thermometer,

graduated cylinder, lever balance, microscope are used in an observation. It is called as quantitative observation.

• Quantitative observations provide the answer to the questions beginning with ‘’how much’’.

• Write “QL” for Qualitative and “QT” for Quantitative • a. ________ The sky is blue. • b. ________ There are 13 clouds in the sky.• c. ________ Mr. Hasson’s tie is smooth. • d. ________ The guinea pig smells bad. • e. ________ There are 20 students in the class.

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• An experiment generally includes two groups from which observations can be made. One set up is called the control group.

• The other set up is the is called the experimental group. The experimental group differs from the control group in only one factor or condition.

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• Activity variables.

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• 4.Evaluating the results of observations and experiments: If the results of an experiment do not support the hypothesis, it is either reversed or completely abandoned. Proposing hypothesis and testing process are repeated until a valid hypothesis is reached.

• 5. Drawing a conclusion:

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• 6.Theory and law: If the hypothesis is still found to be true after conclusions and other experiments continue to support it ,it is called theory. A good theory explains the facts and also predicts new facts.

• If a theory so well established by experimental evidence in many different situations over many years and can be disproved by no means, it becomes a scientific law.

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EXAMPLE STUDY• A.Observations• 1.Salmon are born in a shallow stream or

river.• 2.Salmon travel thousands of miles to live in

the ocean.• 3.Salmon return to the very stream where

they were born to reproduce.

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• HYPOTHESIS• Salmon find their home stream using their sense

of smell.• EXPERIMENT• Salmon were captured and tagged as they

returned to their home stream .The fish were then transported downstream a few miles to be released again.

• The nostrils of half of the captured fish were plugged to block their sense of smell.

• The fish with the plugged nostrils are the experimental group. The unplugged fish are the control group.

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• RESULTS OF THE EXPERIMENT• Control group Experimental group• All the fish found Half of the fish foundtheir home stream. their home stream.• CONCLUSION• Salmon with plugged noses were not as

successful at finding their home stream because they could not use their sense of smell to find their home. The hypothesis is supported.

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• Activity heads and tails

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• B.Observations• 1.A new artificial sweetener,supersweet is

used in some foods and drinks to reduce calories.

• 2.Some food addivities are known to cause cancer.

• 3. Scientists from a research institution report that another kind of artificial sweetener has been linked to bladder cancer in rats.

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• Supersweet may cause bladder cancer.

• EXPERIMENT

• One hundred rats are used in a controlled experiment with supersweet.

• Fifty rats are given supersweet and fifty rats are given regular sugar.

• C o n t r o l group: Exactly like the experimental group except the rats do not receive supersweet.

• Experimental group: All the rats receive supersweet• At the end of the experiment all the rats are autopsied

for cancer.

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• RESULT OF THE EXPERIMENT• Control group: One of the fifty rats developed

bladder cancer• Experimental group: Nine of the fifty rats

developed bladder cancer.• CONCLUSION• Supersweet appears to cause bladder cancer in

rats. It may also cause cancer in man.Further studies will need to be conducted to determine if supersweet is an agent for causing cancer in man.

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Career planning about biology2013 2014

• Genetic engineering is the most popular area of biology. Human Genetic code sequence is determined by Human Genome Project. But still we have unknowns about the genetic material. By determining the sequence we can determine the genetic diseases, transfer genes to cure diseases.

• DNA can be used to identify people. Many criminals can be identified by their DNA sequences. This process is called DNA fingerprinting.DNA sequences are compared and criminals or relations can be determined.

• DNA make up of cells are changed by some techniques to have different genetic code. By this process new characteristics are transferred to DNA. Some parts of DNA is broken down and transferred to new cell. In agriculture by this method resistant plants can be produced. In pharmacy genetically different bacteria can be produced to make drugs.

• Genetic disorders can be treated by this way. By gene therapy new genes can be inserted to the DNA of a cell. With this method many diseases can be treated.

• Infectious diseases cause death of humans, plants and animals. These organisms can be used as biological weapons in wars. (Anthrax, plague )

• For national defense, treatment of these diseases is important.

• Clone is a group of organisms or cells that are genetically identical. Cloning can be important in increasing the number of endangered plants or animals. It can be important in curing some diseases by forming new cells. Paralysis, multiple sclerosis.

If you were a biologist What new discovery would you like to find?

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• Activity tarsia

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