Biology as a Scientific Discipline

A scientific discipline is an organised field of knowledge that uses scientific methods to investigate questions and explain natural phenomena.

Biology is a scientific discipline because it involves the following:

Observation: Carefully examining living things and their activities.
Experimentation: Carrying out investigations to test ideas.
Evidence: Collecting information to support or reject explanations.
Measurement: Recording quantities such as temperature, mass, length and time.
Analysis: Interpreting collected data.
Conclusion: Explaining what the results show.
Verification: Allowing other scientists to repeat investigations and check the results.

Biology relies on evidence rather than mere guesses or unsupported opinions.

Branches of Biology

Biology has several branches, each concerned with particular aspects of life.

Botany: Study of plants.
Zoology: Study of animals.
Microbiology: Study of microorganisms.
Ecology: Study of relationships between organisms and their environment.
Genetics: Study of heredity and variation.
Anatomy: Study of the structure of organisms and their body parts.
Physiology: Study of how organisms and their body parts function.
Cytology (Cell Biology): Study of cells.
Histology: Study of tissues.
Taxonomy: Identification, naming and classification of organisms.
Embryology: Study of the development of an organism from its early stages.
Evolutionary Biology: Study of how populations and species change over generations.
Parasitology: Study of parasites and their relationships with hosts.
Biotechnology: Application of organisms, cells or biological processes to produce useful products and services.
Marine Biology: Study of organisms living in marine environments.
Entomology: Study of insects.
Ornithology: Study of birds.
Mycology: Study of fungi.
Immunology: Study of the immune system and how the body defends itself.

Examples of Branches in Everyday Life

A botanist may investigate why maize plants are not growing well.
A zoologist may study the behaviour of fish.
A microbiologist may identify microorganisms in a laboratory sample.
An ecologist may investigate the effects of pollution on a river.
A geneticist may study how certain characteristics pass from parents to offspring.

Relationship Between Biology and Other Sciences

Biology is closely related to other scientific disciplines. Many biological problems can only be properly understood by combining knowledge from different fields.

Biology and Chemistry

Chemistry studies substances and chemical reactions in living organisms. Digestion and photosynthesis involve chemical reactions.

Biology and Physics

Physics explains forces, energy, pressure, light and movement in organisms. For example, the eye uses light to form images.

Biology and Mathematics

Mathematics helps with calculations, measurements, statistics and biological data. For example, it can be used to calculate the percentage of seeds that germinate.

Biology and Geography

Geography explains the distribution of organisms and the effects of climate and location. For example, scientists study vegetation in different regions of Nigeria.

Biology and Computer Science

Computer science provides tools for storing, analysing and interpreting biological information. For example, scientists use software to analyse DNA sequences.

Biology and Environmental Science

Environmental science combines biological and physical knowledge to understand environmental problems, such as water pollution and its effects on fish.

Biology and Medicine

Medicine applies biological knowledge to health, diagnosis and treatment. For example, understanding how diseases affect body organs helps healthcare professionals manage illnesses.

Biology and Agriculture

Agriculture applies biology to crop production, animal husbandry and soil management. For example, farmers may select crop varieties that resist diseases.

Interdisciplinary Fields

When biology combines with another scientific discipline, new fields may emerge.

Biochemistry: Biology combined with chemistry.
Biophysics: Biology combined with physics.
Bioinformatics: Biology combined with computing and information analysis.
Biostatistics: Biology combined with statistics.
Biogeography: Biology combined with geography.

Scientific Inquiry

Scientific inquiry is the systematic process of asking questions about the natural world and investigating them using observations, evidence and logical reasoning.

It enables scientists to investigate problems, test explanations and develop reliable knowledge.

Scientific inquiry may involve observation, experimentation, fieldwork, measurement, research and analysis of existing information.

Characteristics of Scientific Inquiry

It begins with a question or problem.
It involves careful observation.
It uses evidence and measurable information.
It encourages critical thinking.
It tests explanations against evidence.
It allows findings to be checked or repeated.
It accepts that explanations may be revised when new evidence becomes available.

The Scientific Method

The scientific method is an organised approach used to investigate a scientific problem. The steps may vary depending on the type of investigation; scientists do not always follow them in exactly the same order.

Identifying a Problem

The scientist identifies a question that needs an answer.

Example: Does the amount of light affect the growth of a bean plant?

Making Observations

The scientist observes the situation and gathers background information.

Example: A bean plant near a sunny window appears greener than one kept in a dark cupboard.

Forming a Hypothesis

A hypothesis is a testable proposed explanation or prediction about an observation.

Example: Bean plants receiving sufficient light will grow better than similar plants kept in darkness.

A hypothesis must be capable of being tested using evidence.

Planning and Conducting an Investigation

The scientist designs an experiment and identifies the factors that may affect the result.

Example: Grow two similar bean plants using equal amounts of soil and water, but expose them to different light conditions.

Collecting and Analysing Data

Data are the information gathered during an investigation.

There are two main types of data:

Quantitative data: Numerical information, such as plant height in centimetres.
Qualitative data: Descriptive information, such as leaf colour or appearance.

The scientist records measurements in a table, compares results and looks for patterns.

Drawing a Conclusion

The conclusion explains whether the evidence supports the hypothesis.

A conclusion should be based on the actual results, not on what the scientist wants to happen.

Communicating Findings

The scientist presents the method, results and conclusion in a report, graph, table or presentation. Other scientists may repeat the investigation to see whether similar results are obtained.

Important Terms in Scientific Investigation

Hypothesis: A testable proposed explanation or prediction.

Variable: A factor that can change or be changed in an investigation.

Independent Variable: The factor deliberately changed by the investigator.

Dependent Variable: The factor measured or observed to determine the effect of the change.

Controlled Variables: Factors kept the same to make the comparison fair.

Control Group or Control Condition: A comparison condition used to help determine whether the tested factor caused a difference.

Data: Information collected during an investigation.

Experiment: A planned procedure used to investigate a question or test a hypothesis.

Scientific Theory: A well-supported scientific explanation based on extensive evidence. In science, a theory is not merely an untested guess.

Scientific Law: A scientific statement describing a consistent pattern or relationship in nature. Scientific laws and theories serve different purposes.

Basic Scientific Investigations in Biology

Biologists conduct investigations in laboratories, classrooms, gardens, farms, forests and other environments.

Investigation: Effect of Light on Seedling Growth

Aim: To investigate the effect of light on the growth of bean seedlings.

Materials Required:

Two similar potted bean seedlings.
Water.
Ruler.
Labels.

Procedure:

Label the seedlings A and B.
Place seedling A in a well-lit area.
Place seedling B in a dark location, ensuring safe ventilation and suitable temperature.
Give both seedlings equal amounts of water.
Measure their heights regularly for several days.
Record the height and appearance of each seedling.
Compare the results.

Variables:

Independent variable: Light exposure.
Dependent variables: Seedling height and appearance.
Controlled variables: Plant species, soil type, amount of water, pot size and observation period.

Expected Observation:

The seedling deprived of light may become pale and elongated, while the well-lit seedling is more likely to develop green leaves. Long-term darkness can harm the plant.

Conclusion:

Light influences normal plant growth and development.

Investigation: Conditions Required for Seed Germination

Aim: To investigate the effect of water on seed germination.

Materials Required:

Similar bean seeds.
Two containers.
Cotton wool.
Water.

Procedure:

Place equal numbers of seeds on cotton wool in two containers.
Moisten the cotton wool in container A.
Keep the cotton wool in container B dry.
Keep both containers under similar temperature and light conditions.
Observe the seeds daily and record the number that germinates.

Expected Observation:

Seeds in the moist container are more likely to germinate, provided they receive adequate oxygen and suitable warmth.

Conclusion:

Water is necessary for normal seed germination. Seeds also require oxygen and a suitable temperature.

Investigation: Estimating Plant Population in a School Field

Aim: To estimate the distribution of small plants in a grassy area.

Materials Required:

A quadrat.
Measuring tape.
Notebook.
Pencil.

Procedure:

Select a suitable grassy area.
Place the quadrat at several representative locations.
Count the selected plants inside each quadrat.
Record the counts.
Calculate the mean number of plants per quadrat.

This investigation introduces sampling, counting and the use of mathematics in ecology.

Precautions During Biological Investigations

Follow the teacher's instructions.
Handle glassware and laboratory equipment carefully.
Do not taste or directly smell unknown substances.
Do not handle unknown microorganisms or collect unsafe biological samples.
Use clean equipment and wash your hands after practical work.
Keep experimental conditions as similar as possible except for the factor being investigated.
Record results honestly, even when they do not support the hypothesis.