1.1 THE METHODS OF SCIENCE
Science is an organized system for the systematic study of particular aspects of the natural world. The scope of
science is limited to those things that can be apprehended by the senses (sight, touch, hearing, etc.). Generally, science stresses
an objective approach to the phenomena that are studied. Questions about nature addressed by scientists tend to emphasize
how things occur rather than why they occur. It involves the application of the scientific method to problems formulated by
trained minds in particular disciplines. In the broadest sense, the scientific method refers to the working habits of practicing
scientists as their curiosity guides them in discerning regularities and relationships among the phenomena they are studying. A
rigorous application of common sense to the study and analysis of data also describes the methods of science. In a more
formal sense, the scientific method refers to the model for research developed by Francis Bacon (1561-1626). This model
involves the following sequence:
1. Identifying the problem
2. Collecting data within the problem area (by observations, measurements, etc.)
3. Sifting the data for correlations, meaningful connections, and regularities
4. Formulating a hypothesis (a generalization), which is an educated guess that explains the existing data and
suggests further avenues of investigation
5. Testing the hypothesis rigorously by gathering new data
6. Confirming, modifying, or rejecting the hypothesis in light of the new findings
1.2.WHAT IS A LIVING ORGANISM ?
A living organism is primarily physicochemical material that demonstrates a high degree of complexity, is capable of
self-regulation, possesses a metabolism, and perpetuates itself through time. To many biologists, life is an arbitrary stage in
the growing complexity of matter, with no sharp dividing line between the living and non-living worlds.
Living substance is composed of a highly structured array of macromolecules, such as proteins, lipids, nucleic acids,
and polysaccharides, as well as smaller organic and inorganic molecules. A living organism has built-in regulatory
mechanisms and interacts with the environment to sustain its structural and functional integrity. All reactions occurring within
an individual living unit are called its metabolism. Specific molecules containing information in their structure are utilized
both in the regulation of internal reactions and in the production of new living units.
1.3 WHAT ARE THE ATTRIBUTES OF LIVING ORGANISMS?
Living organisms generally demonstrate:
1. Movement: the motions within the organisms or movement of the organisms from one place to another (locomotion)
2. Irritability: the capacity of organisms to respond in a characteristic manner to changes-known as stimuli-in the
internal and external environments
3. Growth: the ability of organisms to increase their mass of living material by assimilating new materials from the
4. Adaptation: the tendency of organisms to undergo or institute changes in their structure, function, or behavior that
improve their capacity to survive in a particular environment
5. Reproduction: the ability of organisms to produce new individuals like themselves
►11. ATOM. All matter is built up of simple units called atoms. Although the word atom means something that cannot be cut (a =
“without,” tom = “cut”), these elementary particles are actually made up of many smaller parts, which are themselves further divisible.
Elements are substances that consist of the same kinds of atoms. Compounds consist of units called molecules, which are intimate
associations of atoms (in the case of compounds, different atoms) joined in precise arrangements.