Biology,
study of living things and their vital processes. The field deals
with all the physicochemical aspects of life. The modern tendency
toward cross-disciplinary research and the unification of scientific knowledge
and investigation from different fields has resulted in significant overlap of
the field of biology with other scientific disciplines.
Biology
is a natural science discipline that studies living things. It is a very large
and broad field due to the wide variety of life found on Earth, so individual
biologists normally focus on specific fields. These fields are either
categorized by the scale of life or by the types of organisms studied.
Biology is
the scientific study of life. It is a natural
science with a broad scope but has several unifying themes that tie it
together as a single, coherent field. For instance, all organisms are
made up of cells that process hereditary information
encoded in genes,
which can be transmitted to future generations.
Biology
is the study of life. The word “biology” is derived from the Greek
words “bios” (meaning life) and “logos” (meaning
“study”). In general, biologists study the structure, function,
growth, origin, evolution and
distribution of living organisms.
..
The word Biology is derived from two Greek words, Bios which means Life, and logos which means study of. Thus biology is a study of life and living organisms.
Basic Concepts and Terminologies of Biology
Biology
Biology is derived from two Greek words, that is, bios which means life and logos or logia which means study or knowledge.
So biology can be defined as a branch of science which deals with the study of life. The term biology can also be defined as a branch of science which deals with the study of living things or organisms.
Biologist
A person specialized in the study of biology
Life
Life means being alive or existing. Something is alive or existing if it possesses life processes. The life processes are growth, movement or locomotion, respiration, excretion, reproduction, sensitivity and nutrition.
Organism
Organism is anything which has life. It is the other name of a living thing.Organisms are made up of cells.
Cell
A cell is a basic unit of living things. The cell has three main parts, cell membrane, cytoplasmand nucleus. Cells which make up plants are called plant cells and those which make up animals are called animal cells.
Some organisms are made up of one cell. They are called unicellular or single-celled organisms e.g. amoeba, euglena and yeast. Some organisms are made up of many cells, they are called multi cellular organisms e.g. animals, plants, and most fungi.
The Characteristics of Living Things
Outline the characteristics of living things
Movement/locomotion
All living organisms are capable of movement. Movement is the change of position of the whole organism or just part of an organism. For animals and unicellular organisms the movement is of the whole body. This is known as locomotion. Most animals move about using legs, wings or fins. Unicellular organisms such as amoeba, paramecium and euglena use the locomotory structures pseudopodia, cilia and flagella respectively.
In plants only part of it may move towards different factors such as light, water, gravity etc. They move by growing. Their roots grow down in the soil and their shoots grow up into the air or towards a source of light.
Irritability (sensitivity)
Irritability is the ability of an organism to respond to a stimulus. Stimulus (plural; stimuli) is anything that causes a response in an organism.
Examples of stimuli include: an alarm clock, a smell of breakfast cooking and a fly landing on your skin.
All living things are sensitive to certain changes in their surroundings, that is, they are aware of what is happening around them. This is possible because they have special organs known as sense organs by which they detect these changes.
Examples of sense organs include: eyes for vision (sight); skin for temperature, touch, pressure detection; tongue for tasting; nose for smelling; and ears for hearing and body balance.
Plants do not have sense organs but are still able to detect and respond to things like gravity, water and light.
Feeding (Nutrition)
All living things need food to provide energy for such activities such as growth, repair and health.
Animals get their food by eating other living things or food materials that were once living things. Herbivores (e.g. rabbits) eat plants, carnivores (e.g. lions) eat other animals, and omnivores (e.g. humans) eat animals and plants. Plants make their own food through the process called photosynthesis.
The process of taking in food, synthesizing it, digesting and oxidizing it to release energy or build the body is called nutrition.
Respiration
Respiration is the breaking down of food materials within cells to release energy.
Respiration usually involves the use of oxygen. All living things need energy for movement, growth and development, and functioning of body organs.
Excretion
All living things produce wastes such as carbon dioxide, water, urea, ammonia etc.. Some of these chemicals if left to accumulate in the cells would seriously poison the living organism hence they need to be removed. The process of removing metabolic waste products from the body of living organisms is called excretion.
Waste products are removed from the body by excretory organs such skin, kidneys, lungs and liver.
Reproduction
Reproduction is the process by which living things produce new individuals of their kind. All living things reproduce, to replace organisms lost by death. If a group of organisms does not reproduce fast enough to replace those which die, the group becomes extinct. Reproduction ensures continuation of life when parent generation dies.
Human beings bear babies; birds hatch chicks; and plants produce seedlings as new organisms, which eventually grow to mature organisms to replace those lost by deaths.
Growth
Growth is defined as an irreversible (permanent) increase in size and dry weight of an organism involving differentiation. All living things need food in order to grow and build up their bodies.
Animals grow until they reach certain adult size, but most plants can grow continuously throughout their lives.
Branches of Biology
Biology is a subject and it has many branches. The main branches are botany and zoologyBotany is a branch of biology which deals with the study of plants. A person who studies botany is called a botanist Zoology is a branch of biology which deals with the study of animals. A person who studies zoology is called a Zoologist
Other branches of biology
Mycology: this is the study of fungi. A person who studies mycology is called a mycologist
Bacteriology: this is the study of bacteria. A person who studies bacteriology is called a bacteriologist.
Virology: this branch of biology deals with the study of viruses. A person who studies virology is called a virologist.
Immunology: is concerned with body defense against diseases and foreign substances. A person who studies immunology is called an immunologist.
Entomology: refers to the study of insects A person who studies entomology is called an entomologist.
Parasitology: this branch deals with study of parasites and their effects on living organisms. A person who studies parasitology is called a parasitologist.
Dermatology: It is concerned with medical study of skin and its diseases. A person who studies dermatology is called a dermatologist
Ecology: Is a branch of biology that deals with relationship among living things and between organisms and their surroundings. A person who studies ecology is called an ecologist
Anatomy: Is the study which deals with structure of living things. A person who studies anatomy is called anatomist
Diagram representing branches of Biology
Endocrinology: This is the study of structure of endocrine glands and the hormones associated by them. A person who studies endocrinology is called an endocrinologist.
Histology: Is the study of structure of tissues A person who studies histology is called an histologist
Cytology: Is the study of structure, composition and function of cells. A person who studies cytology is called a cytologist.
Microbiology: Is devoted to the study of organisms that can be seen only with a microscope e.g. bacteria, viruses, some fungi and some protoctists. A person who studies microbiology is called a microbiologist.
Taxonomy: Is the scientific classification of organisms. A person who studies taxonomy is called a taxonomist.
Genetics: Study of heredity and variation in organisms. A person who studies genetics is called geneticist.
The Importance of Studying Biology
Explain the importance of studying biology
The study of biology is very important to man.
The following is an outlines of why the study of biology is important:
- It helps us to understand ourselves better since we are living things.
- Skills and knowledge of biology can be applied to other scientific fields such as agriculture, forestry medicine, nutrition, pharmacy and veterinary science.
- It helps us to understand our environment better and principles of conserving it.
- Biology helps to answer some important questions such as, what do living things need, why do we resemble with a monkey, why do frogs lay many eggs but only few become adults?
- Knowledge of biology helps us to improve our health since causes, symptoms, transmission and treatment are of various diseases are studied in biology.
- Knowledge of biology helps us to avoid our selves from magical beliefs, superstitions and other traditional taboos.
- Knowledge of genetics helps us to clear some common doubts about certain inherited characteristics e.g. albinism, sickle cell anaemia, haemophilia, etc.
- Knowledge of the structure and chemical composition of the organisms enable us to acquire food, clothes and shelter from them.
Relationship between Biological Science with other Related Fields
Relate biological science with other related fields
Veterinary science (Veterinary medicine)
Veterinary medicine is the branch of medicine that deals with the diseases of animals. Doctors that treat animals are called Veterinarians. Veterinarians are trained to prevent, diagnose and treat illness in large and small animals. Their work is valuable because many animal diseases can be transmitted to human beings e.g. rabies, tuberculosis, tularemia (rabbit fever) anthrax etc. Basic knowledge of biology is required for successful study of veterinary science.
Agriculture
Agriculture is concerned with production of useful plants and animals through farming system. Agriculture provides us with almost all our food. It provides materials for clothing and shelter. It provides materials used for making many industrial products such as paints and medicines. Agriculture uses knowledge of biology to improve plant and animal breeding. Genetically modified organisms (GMOs) ensure better quality, early maturity and high yield products. Crop and animal diseases and pests can only be overcome by applying biological knowledge.
Forestry
A forest is a large area of land covered with trees. It is much more than just trees. It also includes smaller plants such as mosses, shrubs and wild flowers. Forestry is the science of managing forest resources for human benefit. The practice of forestry helps maintain an adequate supply of timber and management of such valuable forest resources such as water, wildlife, grazing areas and recreational areas.
Biology helps in improving the qualities of the trees through manipulating the genetic constitution of the particular plant species.
Climate, soil and water determine the type of plants to be grown which entirely applies biological knowledge. Use of biological control to combat tree pests applies biological principles.
Pharmacy
Pharmacy is the profession concerned with the preparation, distribution and use of drugs. Members of this profession are called pharmacists or druggists. Pharmacy also refers to a place where drugs are prepared or sold The drugs are made depending on the chemical composition of the body of an organism and how they can react with such medicines. Knowledge of biology also helps to know the effects of drugs on living things (pharmacology) and possible remedies to be taken.
Medicine
Medicine is the science and art of preserving health and treating illness. Medicine is a science because it is based on knowledge gained through careful study and experimentation. It is an art because its success depends on how skilfully medical practitioners apply their knowledge in dealing with patients. The goal of medicine include saving lives, relieving suffering and maintaining the dignity of sick people. Biological knowledge helps the doctors, surgeons and nurses to diagnose, treat and prescribe the right medicine to cure the disease.
Biological knowledge will also help them to offer education to the patients on how to prevent themselves from the diseases e.g. purifying drinking water, vaccination against polio, measles and other diseases.
Nutrition
Nutrition is the science which deals with food and how the body uses it. People, like all living things need food to live. Food provides substances that the body needs to build and repair its tissues and to regulate its organs and systems. Food also supplies energy for every action we perform. Knowledge of biology helps to identify the type of food required by an individual based on its quality and quantity.
A table showing differences between plants and animals
Scientific Processes in Biology
Biology, just like other science subjects, involves carrying out experiments. When studying living things simple observation can be made by using our own senses i.e. sight, smell, touch, taste and hearing. The senses can be detected by our sense organs i.e. eye for sight, nose for smell, skin for touch, tongue for taste and ear for hearing.
To Use Own Sense Organs to Make Correct Observations
Use own sense organs to make correct observations
The body sense organs
Measurements of Mass, Length, Temperature and Pulse Rate
Take measurements of mass, length, temperature and pulse rate
Measurements: When carrying out biological investigation measurements like mass, time, temperature, and length are unavoidable.
Instruments used for various measurements:
- Beam balance – for measuring mass
- Thermometer – for measuring temperature
- Clock/stopwatch – for measuring time
- Ruler – for measuring length
- Pulse rate can be measured by using a stethoscope or by pressing the fingers firmly on the skin.
The study of biology like any the science subject involves scientific processes. The scientific processes involved in the study of biology include observation, measurement and experimentation. Through these processes the study of biology becomes possible.
OBSERVATION
Through observation we can learn many scientific phenomena. Observation is made by using our own sense organs. There are five sense organs in the human body which are eyes, ears, the nose, the tongue, and the skin. Each of these organs is specific to a certain type of observation.
The following are sense organs and their associated functions in observation.
Eyes
How can you differentiate between the colors of an egg from that of a ripe pawpaw? In this case in order to answer this question correctly, you must be able to make correct observation. By using your eyes you can observe differences in colors of the two things given and then tell their differences.
We use our eyes as a sense organ for vision. By using our eyes we are able to see and differentiate sizes, colours and shapes of various organisms and hence we can learn about them.
Ears
How can you distinguish between the sound produced by a singing bird and a roaring lion? Sometimes you can just use your ears to study various biological concepts. For example many organisms produce different sounds which we can use to identify them.
Therefore, it is easy for a biologist to know an organism just by hearing the sound without even seeing it. This proves how your ears are very important organs in scientific studies because they are used to identify and differentiate sounds of various living organisms.
Nose
Sometimes in the scientific study we need to smell in order to identify and distinguish between various things. For example, how can you distinguish the smell of a ripe banana from that of a ripe pineapple? As a scientist you must be able to use your nose as a sense organ effectively and successfully. BUT avoid smelling anything in the laboratory without the permission from your teacher or laboratory technician.
Tongue
We use tongue to taste various things. By use of tongue we can differentiate various tastes and be able to discover the type of the taste concerned. For example, one can differentiate salt from sugar solutions by just tasting using the tongue. BUT avoid tasting anything in the laboratory unless you are told do so by the teacher or laboratory technician.
Skin
We can use the skin as a sense organ to detect heat, temperature, pressure and even pain. For example, during a hot day you feel hot while during cold days you feel cold. Even if you close your eyes, and someone rubs your skin using a block of ice, you can simply tell it by just feeling the coldness it imparts to the surface of your skin.
This group of students are conducting an experiment on ‘food tests’ in the school laboratory. Can you tell the sense organs they are using in their study?
MEASUREMENT
Though we can use our sense organs to make observations, the observations alone are not so reliable. Every sense organ has its weakness. Since science lies upon measurable quantities there is a need of measurement. Scientists have been able to design ways to take measurements of various things. Some of the quantities which can successfully be measured include mass, temperature, length and pulse rate.
Measurement of length
We can use eyes to observe the length of various objects. However, our eyes can just tell which object is longer than the other but can not tell us what the exact length of each object is. Tape measure is one of the common instruments that are used for measuring length in our every day life.
Measurement of temperature
We can take the measurement of temperature of a substance just by using our sense organs. For example, by touching something you can tell whether a particular thing is hot or cold. However, you cannot tell exact temperature of an object.
Therefore, to be able to know the exact temperature you need to use an instrument specially designed for measuring the temperature. This is instrument is the thermometer. Using thermometers we are able to know the exact temperature of an object.
Thermometer
Measurement of pulse rate
Pulse rate refers to average beating of your heart. You can find how fast your heart is beating, that is your heart rate, by feeling your pulse.
How to measure your pulse rate
- Sit down comfortably on a chair with the palm of your hand facing upwards.
EXPERIMENTATION
Biology as a science subject involves practical work. In every area of biology, experimentation is necessary. However, there are several procedures to be followed in conducting any scientific investigation. These procedures include the following:
Identification of a problem (problem statement)
In our day to day life we often come across questions or phenomena which require explanations. Such questions or phenomena are of interest to a biologist who will seek to provide answers to them.
The phenomena could be for example; it was observed that the harvest of tomatoes in Juma’s garden was low despite frequent irrigation, correct planting techniques, timely planting and adequate sunlight. So, what was the problem with Juma’s garden?
This is the problem to be investigated by the biologist in order to come up with an answer.
Hypothesis formulation
Hypothesis is a tentative explanation for the observation made. Using your example of low yield in the tomato garden, the possible hypothesis could be poor yield could have been caused by low soil fertility and therefore application of the fertilizer could increase harvest of the tomatoes in the garden. This hypothesis must therefore be tested by experimentation if it has to be a scientifically acceptable explanation.
Experimentation
An experiment is a series of investigation intended to discover relationship or certain facts that may lead to finding a problem. In the case of low harvest of tomatoes, you are first supposed to construct a plan of investigation as follows:
Select two plots, A and B, from the same garden and subject both of them to the same conditions as before. In plot B apply fertilizers while in plot A don’t put any fertilizers (plot A will be your control plot).
Observation and data recording
After setting up an experiment, a researcher must observe and record data. Observation is done by using sense organs such as ears, eyes, nose and skin. The researcher must record whatever he observes. The researcher obtained X kg in plot A and Y kg in plot B.
Interpretation of data
Once a researcher has collected data, he should try to explain the meaning of data in relation to the purpose of the experiment. In the tomato garden experiment, the harvest in plot A was little compared to the harvest in plot B.
In these plots, all the conditions were the same except that in plot A no fertilizers were applied while in plot B fertilizers were applied. Therefore, high harvest in plot B was a result of applying fertilizers. If this experimentation is correct, then the same results should be obtained if the experiment is repeated under the same conditions.
Conclusion
At the end of investigation, a researcher must draw conclusion. This conclusion is based on the collected data. The conclusion is either confirmation or rejection of the hypothesis under investigation.
In the tomato garden experiment, the results have shown that application of fertilizers has increased the harvest of tomatoes. Therefore, low harvest of tomatoes was caused by poor soil fertility.
Summary
The following diagram summarizes the scientific process.
The scientific process
The Biology Laboratory
Describe the biology laboratory
A biology laboratory is a room or building specially designed for carrying out biological experiments.
A biology laboratory has:
- Large windows and big space to allow enough air and light for better ventilation and visibility respectively.
- Shelves – for keeping chemicals, specimens, apparatus and models.
- Supply of gas, electricity and water
- Working benches
- An emergence door in case of danger occurs.
- Preparation room
The biology laboratory rules
Biology laboratory has sophisticated instruments which need to be handled with special care. Chemicals which are being used are potentially harmful and they need a special attention when working with them.
The following laboratory rules should be adhered to:
- Don’t enter in the laboratory without permission from the teacher or laboratory technician.
- Do not play, or run unnecessarily in the laboratory.
- Do not eat or drink in the laboratory.
- Do not use chemicals or handle apparatus or specimens without instruction from the teacher or laboratory technician.
- Any accident or damage of apparatus must be reported.
- Label chemicals and specimens to avoid confusion.
- Always keep flammable substances away from flames.
- Turn off water and gas taps after use.
- Never point the open end of the test tube to your fellow or yourself when heating.
- Never smell substances, specimens, chemicals or gases directly.
