Scientific Method and Characteristics of Living Things
The Scientific Method
The scientific method refers to the commonly accepted procedures followed by the scientific community. It consists of five stages:
- Observation: The object defines the problem to be explained. Data related to a particular phenomenon is collected and sorted.
- Hypothesis: Possible explanations for the observed problem are proposed.
- Experimentation: Different experiments are designed to test the hypothesis, focusing on the phenomenon under study.
- Analysis of Results: The results are analyzed and compared with those expected if the hypothesis were true.
- Establishment of a Scientific Law: If the hypothesis is repeatedly verified through observation and experimentation, it leads to the formulation of scientific theories or laws.
Requirements for a Hypothesis
A hypothesis must be:
- Formulated in clear and concrete terms.
- Able to explain the cause-and-effect relationship between the facts.
- Comparable, objective, provable, and reproducible.
A hypothesis must be subjected to testing and verification. It remains provisional as long as it is not disproven. If incorrect, it should be rejected, amended, or reformulated.
Variables of an Experiment
To determine which variable(s) influence the phenomenon under study, qualitative or quantitative variables are analyzed one by one.
- Independent Variable: Controlled by the researcher.
- Dependent Variable: Measured and modified in response to the independent variable.
- Control Group: Analyzed under normal conditions without any change in the independent variable.
Data Processing
Data are organized in a table of values. The independent variable is typically placed on the left, and the dependent variable on the right. Graphs are created from this data, with the independent variable on the x-axis (abscissa) and the dependent variable on the y-axis (ordinate). Bar charts and pie charts are also used.
Drawing Conclusions
The data obtained allow us to corroborate or refute the hypothesis. If the hypothesis is confirmed, a scientific law is established. When this law is integrated with other laws related to interconnected phenomena, it forms a scientific theory (which is also provisional).
Study Skills in Biology
Microscopic Techniques
- Non-Optical Techniques: Conducted without any optical instruments.
- Optical Techniques: Conducted using optical instruments.
Types of Studies
- In Vivo Studies: The study of living organisms is performed on the living organism under the same conditions.
- Ex Situ: Studies conducted outside of the organism’s natural environment.
- In Situ: Studies conducted in the organism’s natural environment.
Cell Culture
Cell multiplication is performed in a culture dish with an artificial nutrient medium. This ensures cell survival and proliferation, maintaining all metabolic functions similarly to their natural state. These cultures, derived from cells dispersed from the original tissue, are called primary cultures. Some cells from these primary cultures can be separated and used to create a secondary culture.
Characteristics of Living Things
- Organization: The matter constituting living organisms is organized into various levels of structural complexity.
- Exchange of Matter and Energy: Achieved through food intake and nutrition.
- Respiration: Releases energy necessary for vital functions, producing CO2 that needs to be removed.
- Release of Waste Products: Waste substances are generated by nutrition and respiration.
- Response to Environmental Changes: The ability to capture environmental stimuli and respond to them (Homeostasis).
- Growth: Increase in size and/or cell number.
- Reproduction: Capable of producing offspring similar to the parents.
- Life Cycle: Phases that occur in an orderly manner over time, constituting the organism’s life cycle.