Biologists apply the methods of science to arrive at an understanding of living organisms. Within the context of biology, it is useful to regard life as complex matter that is susceptible to analysis by chemical and physical approaches. Although there are many phenomena within living systems that appear to lie beyond this mechanistic approach, biologists have been most successful at reaching an understanding of life by focusing on those processes involving transformations of matter and energy.
A living organism may thus be defined as a complex unit of physicochemical materials that is capable of self-regulation, metabolism, and reproduction. Furthermore, a living organism demonstrates the ability to interact with its environment, grow, move, and adapt.
Biologists cannot study all of life in their own lifetimes. Therefore, they divide the vastness of the living world into many different kinds of organisms and may combine their investigations to a particular type of organism or, alternatively, may study particular aspects of different kinds of organisms and their interactions with one another.
For example Entomologists, specialists in insect biology, devote their efforts to understanding the various facets of insects but do not become involved with other kinds of organisms. On the other hand, developmental biologists investigate the characteristics of embryo development in many different kinds of organisms but do not venture into investigating other areas.
The boundaries that mark these different areas of investigation provide biology with its specific disciplines, but these boundaries are in a constant state of flux.
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:
- Identifying the problem
- Collecting data within the problem area (by observations, measurements, etc.)
- Sifting the data for correlations, meaningful connections, and regularities
- Formulating a hypothesis (a generalization), which is an educated guess that explains the existing data and suggests further avenues of investigation
- Testing the hypothesis rigorously by gathering new data
- Confirming, modifying, or rejecting the hypothesis in light of the new findings
Scientists may be interested in different aspects of nature, but they use a similar intellectual approach to guide their investigations. Scientists must ?rst formulate a problem to which they can then seek an answer. The answer generally involves an explanation relating to order or process in nature. The scientist is primarily interested in the mechanisms by which the natural world works rather than in questions of ultimate purpose.
Once a question has been raised, the scientist seeks answers by collecting data relevant to the problem. The data, which may consist of observations, measurements, counts, and a review of past records, are carefully sifted for regularity and relationships.
An educated guess, called a hypothesis, is then drawn up; this places the data into a conceptual framework. The hypothesis makes up the lattice-work upon which scientific understanding is structured. Often called an ‘‘educated guess,’’ the hypothesis constitutes a generalization that describes the state of affairs within an area of investigation. The formulation of fruitful hypotheses is the hallmark of the creative scientific imagination. Inductive logic is used to formulate a hypothesis.
In logic, induction usually refers to a movement from the particular to the general. Thus, the creation of a hypothesis (a generalization) from the particulars (specifics) of the data constitutes an inductive leap within the scientific method. Since the scientific method involves such an inductive process at its very core, it is often described as the inductive method. It is of considerable historic interest that Bacon, who first developed what we now call the scientific method, was extremely suspicious of the inductive step for the development of hypotheses.
He thought that with the garnering of sufficient data and the establishment of a large network of museums, the hidden truths of nature would be apparent without invoking induction.
EXAMPLE : A man takes up bird watching and has occasion to observe mated pairs of many different kinds of birds. The man repeatedly sees only the drabber bird of any given pair lay eggs. From these observations, the man concludes that all male birds are colorful and all female birds are drab.
A hypothesis must be both logical and testable. Although the conclusion in Example below demonstrates the use of inductive logic, the conclusion cannot be tested and so, as stated, is useless as a scientific hypothesis.
Deductive logic, in which the thought process is from the general to the specific, is used to state a hypothesis that can be tested. The ‘‘If . . . , then . . . ’’ format is often used for this.
EXAMPLE 2: The conclusion in the previous example could be restated as: If birds of a particular species (i.e., birds capable of interbreeding to produce viable young) differ in color, then the more colorful ones are the males.*
After a workable hypothesis has been formulated, it is tested by constructing experiments and gathering new data, which in the end will either support or refute the hypothesis. Note: The application of the scientific method can be used to disprove a hypothesis, but it can never prove anything absolutely. Hence,a hypothesis that withstands the rigors of today’s tests may have to be altered in the light of tomorrow’s evidence.
An experiment must be so structured that the data gathered are free of bias and sampling error. Therefore, the validity of an experiment depends on a careful selection of organisms for the control and experimental groups, so that differences in age, genetic factors, previous treatment, etc., will not influence the results. Adequate numbers of individuals within each group are also crucial, since with small groups, individual peculiarities may be magnified. In addition, an experiment must be reproducible—i.e., other scientists must be able to repeat the experiment and get the same results.