ICSE Class 9 Biology Chapter 01 Introducing Biology

Introducing Biology

Scope and Branches

You are studying biology as a part of science. It is, therefore, necessary, first, to define science.

Science is an organised body of knowledge supported by observation and experimentation, derived from the study of natural phenomena of the entire material universe.

There are three major branches of science, namely, Physics, Chemistry and Biology. Of these, "Biology" is the study of living beings, that is, all plants and animals including humans.

Nowadays, scientists often prefer the term "Life Science" instead of "Biology" in an effort to emphasize the focus on the study of life processes. However, "Biology" itself means the study or science of life (Greek: bios = life; logos = study).

Growth of Biology

No one can say when the study of biology exactly began. Primitive man lived in jungles and caves. He collected food from natural vegetation and hunted wild animals. Through this activity he learnt about the life and habits of different animals, and recognized various plants and their parts. That was the beginning of Biology. The drawings of animals and plants in the caves of prehistoric periods are proofs of primitive man's interest in the plants and animals around him.

With the evolution of culture, man began to live in settled communities and started farming. He domesticated animals such as the dog, cow, sheep, horse and buffalo. These practices gave him further opportunities for the study of the ways and life of these animals. Thus biology grew more and more.

Greeks were probably the pioneers of an organized study of Biology.

Aristotle (384-322 B.C.) was the first person to study animals in sufficient detail and he is called the founder or "Father of Biology".

Theophrastus (370-285 B.C.) mainly studied plants, and is said to be the "Father of Botany".

Hippocrates (460-377 B.C.) rationalized the science of healing and treating the sick. He is called the "Father of Medicine".

Biology had flourished a great deal in ancient India (2500 B.C. to 650 B.C.). Various systems of classifying animals and plants were developed, for example, Jeevaj (viviparous) animals who give birth to young one, Andaj (oviparous) animals who lay eggs, etc. Cultivation of rice was first introduced in India. It is estimated that more than 1,000 varieties of rice had been developed.

With the invention of microscope in the sixteenth century, a new world of minute animals and plants came to human knowledge. The cell as the basic unit of living things was seen through the compound microscope. Biology now began to grow faster.

Teacher's Note

The history of biology shows how human curiosity about living things evolved from cave paintings to modern science, much like how you observe insects in your garden and wonder about their behavior.

In the nineteenth century, biology took several major leaps through the discovery of germs, wider acceptance of the theory of organic evolution, establishment of the cell theory, etc.

Now, the twenty-first century is poised to unravel more mysteries of nature, and miraculous innovations in medicine and agriculture. Biology has already progressed a great deal in the field of vitamins, hormones, genetics, genetic engineering, antibiotics, cancer research, cloning, stem cell research, organ transplant, environmental sciences, life in outer space, etc. The latest is that scientists are planning to create life, some single-celled bacteria, from lifeless material using fatty acids and nucleotides, etc.

Branches of Biology

Biology is divided into several branches. This division can be made in at least three different ways:

A. In terms of major kinds of organisms.

Botany - the study of plants.

Zoology - the study of animals.

Human Biology - the study of man as a living organism and his relationship with other living organisms. The study of man and human society comes under Anthropology (Gk. anthropos: man; logos: study).

B. In terms of special groups of organisms.

Bacteriology - the study of bacteria.

Virology - the study of viruses.

Mycology - the study of fungi.

Entomology - the study of insects.

Ichthyology - the study of fishes.

Herpetology - the study of lizards, snakes, etc.

Ornithology - the study of birds.

Teacher's Note

These different branches of biology are like different departments in a hospital - each specializes in different areas, just as a heart doctor specializes differently from a skin doctor.

C. In terms of approach on studying it.

Anatomy - the study of gross structure of an organism as seen in dissection.

Morphology - the study of form and structure of plants and animals. It includes (essentially) the understanding and interpretation of structure (both external and internal). [Sometimes students wrongly consider morphology to be concerned with the study of external parts only.]

Histology - the study of minute structure of tiny bits of the body as seen with the help of a compound microscope.

Cytology - the study of structure and function of animal and plant cells.

Physiology - the study of functions and activities of organisms and their parts.

Embryology - the study of formation and development of embryo of plants and animals.

Taxonomy - the science of naming, grouping and classifying plants and animals. It is also called Systematics.

Ecology - the study of the relationship of an organism to both its living and non-living environment.

Biogeography - the study of geographical distribution of plants and animals.

Palaeontology - the study of prehistoric forms of life through fossils of plants and animals.

Evolution - the study of origin and descent of organisms.

Genetics - the science of the transmission of body characteristics (both similarities and differences) from parents to offspring. A story, "MY BEAUTY AND YOUR INTELLIGENCE!" It says that a young charming prostitute once approached the great litterateur Bernard Shaw with the proposal of marrying him so that the child they get shall be beautiful like her and intelligent like him. Shaw retorted saying if it happened the other way, that is, his appearance and her brain, then?] This is just one of the aspects of Genetics.

Parasitology - the study of parasites (the organisms that live on or inside other organisms and draw nourishment from the hosts).

Pathology - the study of diseases of plants and animals.

Immunology - the science that deals with the phenomena and causes of immunity (resistance to or defence against diseases).

Eugenics - the science which aims to improve the human race through controlled heredity. For example, discouraging a marriage are likely to show unfavourable or harmful characters in children.

Biochemistry - study of chemicals and reactions that take place inside the living things. One of its numerous applications is DNA fingerprinting.

Teacher's Note

When your doctor examines your blood under a microscope to diagnose an infection, they are using histology and cytology - the same branches of biology you are learning about.

In the nineteenth century, biology took several major leaps through the discovery of germs, wider acceptance of the theory of organic evolution, establishment of the cell theory, etc.

Applied Biology

Biology has enormous applications in other branches of science. It forms an important part of the following:

Agriculture - raising crops and livestock (cow, buffalo, etc.).

Veterinary science - treatment and surgery of animals.

Marine biology - study of life in the sea.

Household biology - study of household animals, insects, etc., including how to prevent damage to our own body and to our belongings.

Horticulture - science and art of growing fruits, vegetables, flowers or ornamental plants.

Sericulture - technique of producing silk by raising silkworms.

Pisciculture - the technique of growing fish.

Molecular Biology - interpreting biological events in terms of molecules in the cell.

Biotechnology - the use of living cells or microorganisms in industry and technology. It includes areas such as bigas production, food processing, genetic engineering, antibiotic production, extraction of extracellular enzymes used as bio-detergents in laundry washing powders, vaccine production, anti-bodies production, tissue culture, etc.

Cloning is a rapidly advancing branch of biotechnology. Several animals have been cloned in which a body cell is used with no involvement of the male sperms. It also includes modifying crops easier to grow and improving their quality.

Bioengineering which includes techniques like the making of artificial limbs, joints and other parts of the body from metals or plastic, etc. It also includes modifying crops easier to grow and improving their food quality.

Nuclear Biology - the study of the effects of radioactivity on living things which is also called Radiation Biology.

Space Biology - the study of survival problems of living things in outer space.

Exobiology is one of the newest sciences, which contemplates to study life elsewhere in the universe.

Genomics - the study of genomes as opposed to individual genes. Genome is the entire DNA sequence of an organism.

Bioinformatics - management and analysis of biological information stored in databases.

Biometrics - the verification of a person by his certain body features such as the pattern of iris in the eye and behavioural characteristics.

Teacher's Note

Biotechnology and genetic engineering are used to create disease-resistant crops and insulin for diabetics, directly improving health in your community.

Study of Biology Helps Us in Many Ways

Appreciation of Nature. The world of plants and animals is so vast and varied that one wonders at it. Despite this variety, biology helps us to understand the basic unity of all living things in their essential features.

Keeping healthy. Biology has helped us to understand the causes of many diseases. It has shown us how germs are spread by certain agents such as insects, wind or water. This knowledge helps us to take proper care of our health and live longer.

Conservation of natural resources. Biology has helped us to understand the inter-dependence of plants and animals. Biology has made both, the people and the governments realize the dangers of cutting down forests and the indiscriminate killing of wild animals. Similarly, this science advocates the conservation of petroleum, coal or metal deposits on our planet.

Growing more food. New varieties of plants and new breeds of cattle, poultry, etc. are being developed with the knowledge of Biology. This science has also increased our knowledge of diseases of plants and animals, and how to cure them. All these efforts are helping us to produce more food in fields, dairies, and poultry farms.

Making us conscious citizens. Biology helps us in solving problems of sanitation, public health, water supply, etc. Biology is making us conscious of the need to reduce the rate of our rapid population growth.

Increasing population, industries and transport are all creating a problem of pollution, endangering human health. Increasing use of insecticides in fields, farms and godowns is added to health hazards. Biology helps us to recognize and take steps against such pollution.

Biology is necessary for certain careers. There are many careers in which are open to students of Biology. One may choose to be a doctor, a dentist, a bacteriologist, a pathologist, a druggist, an entomologist, a forester, a teacher, a veterinary doctor, biotechnologist, etc.

Teacher's Note

Understanding how water becomes contaminated and how to purify it is applied biology that directly affects the water your family drinks every day.

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