Scientific methods of inquiry start with the formulation of hypotheses based on observations and data. Comparative and controlled experiments are carried out to test hypotheses. Statistics are essential for drawing conclusions from the data obtained in experiments. Because organisms can be compared through their evolutionary relationships, the results of experiments can frequently be generalized to apply to other species.
learning outcomes
You should be able to:
Explain the roles of inductive logic and deductive logic in scientific inquiry.
Describe how a controlled experiment is designed.
Differentiate between controlled experiments and comparative experiments.
Explain why model organisms are used in biological research.
What is the relationship between a hypothesis and an experiment?
A hypothesis is a proposed explanation for an observation or a phenomenon. An experiment is a rigorous test of that proposed explanation.
What is controlled in a controlled experiment?
In a controlled experiment, all variables are held constant while one variable is manipulated to determine its effect on the system being studied.
What features characterize questions that can be answered using a comparative approach rather than through a controlled experiment?
When questions involve systems in which variables cannot be controlled, which is the case with many questions in natural systems, a comparative approach can be used to establish correlations between the variable of interest and its possible effects.
Why is it often possible to generalize the results of biological research on one species to very different species?
Since all life is related through evolution, different species use similar molecular, biochemical, cellular, physiological, and even behavioral components, systems, and mechanisms. Therefore what is learned from one species is likely to be applicable to other species.
The vast body of scientific knowledge accumulated over centuries of human civilization allows us to understand and manipulate aspects of the natural world in ways that no other species can. These abilities present us with challenges, opportunities, and above all, responsibilities.