MEANING OF SCIENCE AND BIOLOGY.
- Science can be defined as a systematic process of making inquiry about the living and non-living things in our environment.
- Science is both an organized body of knowledge and a process of finding out knowledge.
- Biology is the branch of science that studies living things.
- The word ‘biology’ is derived from two Greek words: ‘bios’ which means life, and ‘logos’ which means study. Biology therefore means the study of life or of living things.
Biology has several branches, these include
- Botany (study of plants)
- Zoology (study of animals)
- Morphology (study of the external features of living things)
- Anatomy (study of internal structure of living things)
- Physiology (Study of how living things function)
- Ecology (study of the relationships between living things and their environment),
- Genetics (Study of how living things inherit characters from their parents) etc.
The prime purpose of science is research, i.e. finding out about things, so biology involves finding out or making inquiry about living things, their interaction with themselves and with nature.
METHOD OF SCIENCE
- The method of science involves systematically making inquiries about something under study. It begins with observation (that is, looking at something carefully with a view to finding an answer to a question).
- This involves using all the senses i.e. sight, hearing, touch, feeling, pressure, taste, etc. and instruments (e.g. ruler, microscope, magnifying lens, weighing balance, telescopes, barometer, etc.) where necessary.
- Observation is followed by a hypothesis i.e. a sensible, reasonable guess which is capable of being tested or verified.
- The hypothesis is tested by an experiment. Experiments usually involve measurements/counting, as such they have to be carried out as accurately as possible. Scientific experiments have a control.
- The control experiment is identical with the experiment proper, but the factor to be tested is omitted. This gives the investigator a higher degree of confidence in his result and conclusion.
Results from an experiment are put together and a conclusion (inference/generalization) is made.
Other scientists may repeat the same experiment and if similar results are obtained then the generalization is accepted as a theory.
When a theory has been tested extensively, worldwide and found to be consistently true, it becomes a law e.g. the law of gravity.
- Experiments are designed to eliminate all forms of bias so as to avoid making false conclusions. To achieve this, only the factor being tested is varied, all other factors that may affect the result are kept constant. These experiments are known as controlled experiments.
- While experimenting, a biologist uses processes of science such as counting, measuring, classifying, organizing data, communicating, recording and interpreting data.
- In recording an experiment/ giving the account of a scientific investigation, the following pattern is used:
- Date of experiment
- Aim/purpose of experiment
- Apparatus/materials required
- Procedure/method used (including control and precautions)
- Inference (deduction from what is already known)
In biology, experiments are carried out on living things. It may not be possible to get a sample of test population with identical organisms.
- This problem can be reduced by using large test samples and also repeating the experiment many times.
LIVING AND NON LIVING THINGS
- Everything in the world can be classified as either a living thing or non-living thing.
- Living things include plants and animals (things that have life) e.g. Man, Monkey, Earthworm, Flies, Mango, Fresh okra plant, Hibiscus etc.
- Non-living things do not have life e.g. Stone, Water, Air, Table, etc.
CHARACTERISTICS OF LIVING THINGS
- Some features have been found in every living thing ever studied by Biologists, these are;
- Living things consist mainly of water and compounds carbon. They are made up of one or more units called cellsThey carry out seven basic life processes namely;
- This is defined as the ability of an organism to change its position.
- It may be a total change in position of the body as in the case of animals that move their whole body from one place to another or a limited change in position as in the case of plants which can only move parts of their body (e.g. in bending).
- Living things move in order to look for food, shelter, mates (reproduction) and to escape from danger.
- Generally, most animals can walk, swim, or fly from one place to another but plants can only move parts of themselves in response to external stimuli. Movement from place to place is also referred to as Locomotion.
- This is the ability of an organism to feed.
- The reason for feeding is to enable living things to live and carry out life processes like growth, respiration and reproduction.
- Plants manufacture their own food through the process of photosynthesis (autotrophic nutrition).
- Animals cannot manufacture their own food but depend directly or indirectly on plants for food (heterotrophic nutrition).
- This involves the taking in of oxygen in order to burn down (oxidize) food substances to release energy which is used to carry out all life processes. Carbondioxide is given off in the process.
- This is the removal of metabolic waste products from the body. Many chemical activities go on in an organism and produce waste.
- These waste products are substances which the organism does not need and which may poison it if allowed to build up in the body.
- The waste products of metabolism include carbondioxide, water, urea, e. t. c.
Irritability or Sensitivity –
- This is the ability of an organism to perceive and respond to stimuli (changes in the surrounding). Living things exhibits sensitivity in order to survive in their environment.
- The response is often by some form of movement. Stimuli include heat, light, pain, sounds, chemical substances, e.t.c.
- This is defined as permanent increase in size and mass of an organism especially while young.
- Organisms also replace and repair worn or damaged parts of the body throughout life. The food eaten provides the basis of growth.
- This is the ability of a living organism to produce young ones or offspring. This ensures continuity of life.
- Reproduction occurs in two forms.
- Asexual reproduction – This involves only one organism producing offspring from itself.
- Sexual reproduction – This involves two organisms coming together to produce offspring(s).
- Apart from these seven basic life processes another characteristic of living things is that they all die. All living things have a definite and limited period of existence, and they pass through five basic stages of existence;
Birth → Growth → Maturity → Decline (old age) → Death.