Chapter 1: Introducing Biology (Scope and Branches)

In the 1670s, a cloth merchant in the Dutch town of Delft began sending strange letters to the Royal Society in London. His name was Antonie van Leeuwenhoek, and he was not a trained scientist at all.

His trade had taught him to use a lens to count the threads in a piece of cloth. That habit grew into an obsession. He learned to grind tiny glass beads into lenses far better than anyone else could make. Mounted in a small brass plate, one such lens could magnify an object more than two hundred times.

Then he began looking at everything. Rainwater standing in a barrel. Water from a nearby lake. Scrapings from between his own teeth.

In every one of them he found something moving. Tiny shapes swam, spun and darted across his field of view. He called them ‘animalcules’, meaning little animals, and he described their size, their shape and the way they moved.

The scholars in London did not believe him. Nobody had ever suggested that a drop of clear water might be crowded with living things. It took repeated testing by others before his reports were accepted.

Van Leeuwenhoek had not discovered a new animal. He had discovered a whole layer of life that no human eye had ever reached — and biology has been growing outwards, and inwards, ever since.

Diagram

Fig. 1.0-1 — A Simple Microscope Of Van Leeuwenhoek’s Kind Line drawing of a hand-held single-lens microscope: a small flat brass plate held upright, shown from the front and from the side; label the tiny glass lens set in the plate, the pointed specimen pin in front of the lens, the focusing screw, and the eye position behind the lens. Beside it, a small circular inset showing the view through the lens — several differently shaped moving organisms in a drop of pond water. Straight, non-crossing lead lines.

Curiosity Corner

Q1. Van Leeuwenhoek studied living things, yet he was a cloth merchant. What exactly makes a study of nature count as science? Q2. Long before microscopes existed, who first studied plants and animals in an organised way, and what titles do we still give them? Q3. What did the microscope reveal about living things that no one could have guessed by looking with the naked eye? Q4. If you wanted to spend your life studying only bacteria, or only fishes, or only fossils, would biology have a place for you? Q5. How can knowing biology help a farmer grow more food, or a city keep its people healthy?

1.1 Biology As A Branch Of Science

You have been studying science since your earliest classes. Biology is one part of it. So before we ask what biology is, it is worth asking what science itself is.

1.1.1 What Science Is

Everyone notices things. A gardener notices that a plant near the wall grows taller than one in the open. A cook notices that dough kept warm rises faster. Noticing, by itself, is not yet science.

Science begins when such noticing is done carefully, recorded honestly, and then tested. It is knowledge that has been organised, not knowledge that has merely been collected.

Two activities do this work of testing. An observation means watching and recording what actually happens, without changing anything. An experiment means deliberately changing one thing, keeping everything else the same, and watching what follows.

The difference matters. Observation tells you that the plant near the wall is taller. Only an experiment can tell you whether the wall is the reason.

Definition

Science An organised body of knowledge about the natural phenomena of the entire material universe, built up and supported by observation and experimentation.

Notice what this definition rules out. A belief that no one can test, and a fact that no one has checked, are both outside science — however widely they may be held.

Curiosity Corner

Q1. Van Leeuwenhoek studied living things, yet he was a cloth merchant. What exactly makes a study of nature count as science?

A. Not his job, but his method. He observed carefully, recorded exactly what he saw, and reported it so that others could test it. His findings became science when they were checked and confirmed by other people.

Do Not Mix Up

Observation And Experiment An observation records nature as it already is. An experiment changes one factor on purpose and records what follows. Observation shows what happens; experiment shows why.

1.1.2 Where Biology Sits Among The Sciences

Science is very large, so it is divided by the kind of matter it studies. There are three major branches: Physics, Chemistry and Biology. FC 1.1 sets out this division.

Physics studies matter and energy, and the rules that govern motion, heat, light, sound and electricity. Chemistry studies what substances are made of, and how they combine and change into other substances.

Biology takes the part of the material universe that is alive. It studies living beings — all plants and animals, including human beings.

Flowchart

FC 1.1 — The Three Major Branches Of Science Science (study of the material universe) → branches into three: Physics (matter and energy) / Chemistry (substances and their changes) / Biology (living beings)

These three do not stand apart from one another. The energy a leaf traps is a question in physics; the sugar it builds is a question in chemistry; the leaf that does both is a question in biology.

1.1.3 Biology And Life Sciences

The word biology comes from two Greek words: bios, meaning life, and logos, meaning study. Put together, they give exactly what the subject is — the study of life.

Its scope is wider than the plants and animals you can see. It also covers the fungi, the bacteria and the many microscopic organisms of the kind van Leeuwenhoek first reported.

Today scientists often prefer the term life sciences instead of biology. The change of name signals a change of interest.

Naming and describing organisms was once the whole of the subject. It is now only its starting point. The questions that occupy biologists are increasingly about processes: what a cell does, how a signal travels, why a characteristic is passed on.

Try Yourself

Choose one plant growing near your home. Watch it on three days over a week, at the same hour, and write down only what you actually see — leaf position, flowers, insects on it. Then write one question your notes raise that you could test by changing something.

1.2 The Growth Of Biology

No one can say exactly when the study of biology began. It has no founding date, because it began as ordinary human attention to living things — long before anyone thought of calling it a subject.

What we can trace is how that attention grew: first practical, then organised, then written down, and finally armed with instruments. FC 1.2 lays out that path from end to end, and the rest of this section follows it stage by stage.

Flowchart

FC 1.2 — How Biology Grew Through The Ages Early humans watching plants and animals to survive → settled farming and the keeping of domesticated animals → organised Greek study and the first written accounts → classifications and medical writing in ancient India → the microscope opens the world of minute organisms → nineteenth-century leaps: germs, organic evolution, cell theory → twenty-first-century biology of genes, cells and whole ecosystems

1.2.1 The Earliest Observers

The earliest human beings lived in forests and caves. They gathered food from wild vegetation and hunted wild animals.

Survival depended on knowing living things well. Which fruit could be eaten and which made you ill; where a herd moved in which season; which animal turned dangerous when cornered. This was knowledge of the life and habits of other organisms, and it was gathered for use, not for study.

We know they were watching closely because they drew what they watched. Cave walls of prehistoric times carry drawings of animals and plants, some of them accurate enough for us to identify the species today. Fig. 1.2-1 shows two such drawings.

Diagram

Fig. 1.2-1 — Animals Drawn On Prehistoric Cave Walls Two line drawings in the style of prehistoric cave art, one above the other: above, a wild horse in side view with a heavy neck and short upright mane; below, a mammoth in side view with long curved tusks, a domed head and a shaggy coat. Caption space beneath each; no labels on the drawings themselves.

1.2.2 Farming, Herding And Closer Observation

As human culture developed, people stopped moving with the seasons and began to live in settled communities. With settlement came farming.

Settled people also began keeping animals. The dog, the cow, the sheep, the horse and the buffalo were among the animals brought under human care.

This changed the quality of observation completely. An animal you follow through a forest is seen in glimpses. An animal that lives beside you is seen every day, through birth, growth, illness and breeding.

Farming did the same for plants. A field is a place where the same plant is watched from seed to seed, season after season. Biology advanced because human beings had at last placed living things where they could be observed steadily.

1.2.3 The Greek Beginnings Of Organised Study

Knowledge becomes a subject when it is collected, arranged and written down. That step was probably first taken by the Greeks, who are regarded as the pioneers of an organised study of biology.

Aristotle (384–322 BCE) was the first person to study animals in real detail. He dissected them, described hundreds of kinds, and grouped them by their features. For this he is called the founder of biology, and is known as the ‘Father of Biology’ and the ‘Father of Zoology’.

Theophrastus (370–285 BCE) worked mainly on plants. He described their parts, their forms and their uses in an organised way, and is called the ‘Father of Botany’.

Hippocrates (c. 460 – c. 370 BCE) turned to the human body and its illnesses. Before him, disease was widely explained as the work of angry gods. He argued that a disease has a natural cause, and looked for it in the patient’s body, food, water and surroundings. He is called the ‘Father of Medicine’.

Curiosity Corner

Q2. Long before microscopes existed, who first studied plants and animals in an organised way, and what titles do we still give them?

A. The Greeks. Aristotle, who described and grouped animals, is called the Father of Biology and of Zoology; Theophrastus, who did the same for plants, is called the Father of Botany; and Hippocrates, who sought natural causes for disease, is called the Father of Medicine.

Side Note

Titles Given Later No one called Aristotle the Father of Biology in his own lifetime. Such titles are honours awarded much later, by scholars looking back, to mark who took a subject’s first organised step. They recognise a beginning, not a claim to have worked alone.

1.2.4 Biology In Ancient India

Biology also flourished in ancient India, over the long period from about 2500 BCE to 650 BCE. Plants and animals were studied, described and sorted into groups.

Some of these classifications survive in Sanskrit texts. Animals were divided by how their young are produced. Viviparous animals, called Jeevaj, give birth to living young. Oviparous animals, called Andaj, lay eggs from which the young later hatch.

Notice what such a scheme requires. To place an animal in the right group, someone must have watched its breeding closely enough to be sure — which is observation of exactly the kind science depends on.

Crop plants received the same careful attention. Rice was among the earliest crops cultivated in India, and over the centuries farmers here developed a very large number of distinct varieties, each suited to a particular soil, season or depth of water.

Side Note

Written Medicine In Ancient India Two ancient Indian medical works, the Charaka Samhita and the Sushruta Samhita, still survive. Between them they describe hundreds of medicinal plants, methods of diagnosis, and detailed surgical procedures with the instruments used. They are among the earliest organised writings on the human body anywhere.

1.2.5 The Microscope Opens A Hidden World

Until the sixteenth century, biology could study only what the eye could see. The invention of the microscope removed that limit.

A whole world of minute animals and plants, invisible until then, came into human knowledge. Water, soil and even the human body turned out to be crowded with organisms nobody had suspected.

The compound microscope, which uses two lenses in a tube to magnify far more than one lens can, then revealed something deeper. Living bodies are not solid throughout. They are built of tiny compartments, and the cell — the small unit of which every living body is made — came to be recognised as the basic unit of living things.

Real Incident / Discovery

Hooke Names The Cell In 1665, in London, Robert Hooke was examining ordinary objects under a compound microscope he had improved himself. He cut a wafer-thin slice of cork, the bark of a tree, and looked at it. He saw a regular honeycomb of tiny empty boxes with walls between them. They reminded him of the small rooms in which monks lived, called cells, and that is the name he gave them. Hooke was in fact looking at the dead walls left behind by cells, not at living cells; but the name stayed, and biology had gained its most important word.

From this point biology began to grow much faster. Every organ could now be asked a new question — not only what does it do, but what is it made of?

Curiosity Corner

Q3. What did the microscope reveal about living things that no one could have guessed by looking with the naked eye?

A. Two things. First, that there is a whole population of minute organisms living in water, soil and our own bodies. Second, that every living body, however large, is built out of tiny units called cells.

Do Not Mix Up

Simple And Compound Microscope A simple microscope uses a single lens, like a magnifying glass. A compound microscope uses two lenses, one above the other in a tube, so that the second lens magnifies the image made by the first — giving far greater magnification.

1.2.6 The Great Leaps Of The Nineteenth Century

The nineteenth century brought three advances that reshaped the whole subject.

The first was the discovery that many diseases are caused by germs — living organisms too small to see, which enter the body and multiply there. Illness could now be traced to a cause that could be found, grown and fought.

The second was the wider acceptance of the theory of organic evolution, which holds that the species living today have descended, with change, from earlier species. It gave biology a way to explain why organisms resemble one another as they do.

The third was the establishment of the cell theory, the statement that all living organisms are made of cells and that every cell arises from a pre-existing cell. Hooke’s word had become a principle.

Real-World Application

Why Germ Theory Changed Hospitals Once disease was known to be caused by living organisms carried from body to body, the remedy became obvious. Surgeons began cleaning their hands and instruments before operating, wounds were dressed with materials treated to kill germs, and drinking water was separated from sewage. Deaths after surgery and outbreaks of water-borne disease fell sharply. Handwashing before eating and after using a toilet rests on exactly the same reasoning.

1.2.7 Biology In The Twenty-First Century

Biology today is moving faster than in any earlier period, and its progress is felt most directly in medicine and in agriculture.

Vitamins and hormones are now understood well enough to correct the disorders caused by their lack. Antibiotics treat bacterial infections. Cancer research, organ transplantation and stem cell research work on repairing or replacing what has failed in the body.

Other fields work at the level of the gene. Genetics explains how characteristics pass from parents to offspring; genetic engineering alters the genetic material of an organism deliberately; cloning produces individuals that are genetically identical to an existing one.

Biology has also turned outwards. Environmental sciences study how organisms and their surroundings depend on one another, and the survival of living things in outer space is now a working question rather than a fanciful one.

The boldest line of work asks whether life itself can be built. Chemists are attempting to assemble the simplest cell-like systems in the laboratory, using fatty acids to form a membrane and nucleotides to carry information — the two things any living cell must have.

1.3 The Branches Of Biology

Living things are far too many, and too varied, for anyone to study all of them in one lifetime. So biology is divided into branches, and a biologist works inside one or two of them.

The division can be made in at least three different ways. You may divide by the major kind of organism studied, by a special group of organisms, or by the approach taken to the study. Table 1.1 sets the three side by side.

Compare Table

The third way is worth pausing over. A branch such as anatomy or genetics is not tied to any one organism — you may study the anatomy of a bird, of a fish or of a fern. Fig. 1.3-1 shows several of these branches together.

Diagram

Fig. 1.3-1 — Some Principal Sub-Divisions Of Biology A tree drawing rising from a single trunk labelled BIOLOGY at the base, with nine boughs spreading upwards; each bough ends in a circular panel holding a simple line drawing of what that branch studies. Label the boughs: anatomy (gross structure) with a dissected kidney; morphology (interpretation of structure) with a bird in flight; ecology (relation with environment) with two animals in a grassland; genetics (inheritance) with two children showing a shared facial feature; parasitology (parasites) with a roundworm; palaeontology (fossils) with a fossil skeleton in rock; physiology (life processes) with a leaf; embryology (development) with a developing embryo in outline; cytology (cells) with a group of cells; histology (tissues) with a sheet of red blood cells. Straight, non-crossing lead lines.

1.3.1 Branches Named By The Major Kind Of Organism

The oldest division is the simplest one: plants on one side, animals on the other.

Botany — the study of plants.
Zoology — the study of animals.
Human Biology — the study of the human being as a living organism, and of the relationship between humans and other living organisms.

Human biology is set apart because we have a particular interest in ourselves — in our health, and in how our own bodies work.

There is a related subject that is not a branch of biology. The study of human beings and their interaction with society is called anthropology, from the Greek anthropos, meaning man, and logos, meaning study.

1.3.2 Branches Named By A Special Group Of Organisms

Some groups of organisms are so large, or so important to us, that each is studied as a subject in its own right.

Bacteriology — the study of bacteria.
Virology — the study of viruses.
Mycology — the study of fungi.
Phycology, also called Algology — the study of algae.
Entomology — the study of insects.
Ichthyology — the study of fishes.
Herpetology — the study of reptiles such as lizards and snakes.
Ornithology — the study of birds.

Side Note

Names Built From Greek Roots Most branch names are a Greek word for the group plus logos, meaning study. Ornis is a bird, ichthys a fish, entomon an insect, mykes a fungus, phykos a seaweed. Learn the root and the name explains itself.

1.3.3 Branches Named By The Approach Of Study

These branches are defined not by what is studied but by how. Almost any of them can be turned on almost any organism.

Anatomy — the study of the gross structure of the organs of an organism, as seen in dissection.
Morphology — the study of the form and structure of plants and animals. It includes the understanding and interpretation of structure, both external and internal.
Histology — the study of the minute structures of the body at the tissue level, as seen with the help of a compound microscope.
Cytology — the study of the structure and function of animal and plant cells.
Physiology — the study of the metabolism of organisms and their parts, that is, of their functions and activities.
Embryology — the study of the formation and development of the 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 biotic, or living, and its abiotic, or non-living, environment.
Biogeography — the study of the geographical distribution of plants and animals.
Palaeontology — the study of prehistoric forms of life through the fossils of plants and animals.
Evolution — the study of the origin and descent of organisms.
Genetics — the science of the transmission of body characteristics, both similarities and differences, from parents to offspring.
Parasitology — the study of parasites, the organisms that live on or inside other organisms and draw nourishment from those hosts. A parasite living on the surface of the host is an ectoparasite; one living inside the host is an endoparasite.
Pathology — the study of the diseases of plants and animals.
Immunology — the science that deals with the phenomena and causes of immunity, that is, of resistance to and defence against disease.
Eugenics — the idea of improving the inherited qualities of a human population by controlling who has children.
Biochemistry — the study of the chemicals and the chemical reactions that take place inside living things. One of its many applications is DNA fingerprinting.

Two entries in that list need a further word.

The first is morphology. Students often take it to mean the study of external parts only. That is wrong. Morphology covers form inside and out, and its work is to interpret that form — to say what it means and what it is for.

The second is eugenics, and the care it needs is of a different kind. In the twentieth century the idea that a population could be improved by controlling who was allowed to marry and have children was used to justify grave injustice, including the forced sterilisation of people judged unfit. Biologists today reject eugenics on ethical grounds, and also on scientific ones: human characteristics arise from many genes acting together with the environment, and no authority has ever been in a position to decide which of them a population would be better without.

Do Not Mix Up

Morphology And Anatomy Morphology asks what a structure’s form is and what that form means, outside and inside alike. Anatomy asks how the parts are arranged, as revealed by cutting the body open in dissection.

Zoom In / Out

Three Branches, Three Levels One body can be studied at three rungs of the scale ladder. Cytology works at the cell, histology at the tissue, anatomy at the organ. Zoom in from an organ and you reach tissues; zoom in again and you reach cells.

Curiosity Corner

Q4. If you wanted to spend your life studying only bacteria, or only fishes, or only fossils, would biology have a place for you?

A. It has a named branch for each. Bacteria belong to bacteriology, fishes to ichthyology, fossils to palaeontology — and the same holds for viruses, fungi, algae, insects, reptiles and birds.

1.4 Applied Biology

The branches in the previous section exist to find things out. Applied biology exists to put what has been found out to work.

Its reach is wide. Biology forms an important part of farming, of medicine, of industry and of several technologies that did not exist a generation ago. Fig. 1.4-1 shows four of these fields at work.

Diagram

Fig. 1.4-1 — Four Fields Of Applied Biology Four square line-drawing panels in a row, each titled beneath: (1) Apiculture — a wooden hive box with one frame drawn out, comb cells visible, bees on the comb; (2) Sericulture — a mulberry twig with silkworm larvae feeding and two finished cocoons beside it; (3) Pisciculture — a rectangular fish pond in section with fish at different depths and an inlet channel; (4) Horticulture — a nursery bed with young fruit saplings in rows and a grafted stem shown enlarged in an inset. Label the key structure in each panel with straight, non-crossing lead lines.

1.4.1 Applications In Food, Farming And Animal Care

Most of what you eat reaches you because someone applied biology to producing it.

Agriculture — the raising of crops and of livestock such as cattle and buffaloes.
Apiculture — the practice of keeping bees for the manufacture of honey and beeswax.
Veterinary science — the treatment and surgery of animals.
Marine biology — the study of life in the sea.
Household biology — the study of the animals and insects that live in our houses, including how to prevent the damage they do to our bodies and to our belongings.
Horticulture — the science and art of growing fruits, vegetables, flowers and ornamental plants.
Sericulture — the technique of producing silk by raising silkworms.
Pisciculture — the technique of growing fish.

Each of these rests on knowing an organism’s needs exactly. A silkworm will spin its cocoon only if it has been fed the right leaves at the right stage; a fish pond yields well only if its water holds enough dissolved oxygen. India is today among the world’s largest producers of silk, and that output depends on such details being got right.

Try Yourself

Spend ten minutes beside a flowering plant in daylight. Count how many insects visit the flowers, and note whether the same kind returns. Then work out what a beekeeper would need to know about flowering seasons before placing a hive.

1.4.2 Applications Built On Modern Technology

The remaining fields are recent. Most of them became possible only once biology could work at the level of molecules and of information.

Molecular Biology — the interpretation of biological events in terms of the molecules present in the cell.
Biotechnology — the use of living cells or microorganisms in industry and technology. It includes biogas production, food processing, genetic engineering, antibiotic production, the extraction of enzymes used as biodetergents in laundry washing powders, and the production of vaccines, antibodies and tissue cultures.
Cloning — a rapidly advancing branch of biotechnology. It is the process of producing genetically identical individuals of an organism, either naturally or artificially. Several animals have been cloned using an ordinary body cell, with no sperm involved at all.
Bioengineering — the making of artificial limbs, joints and other body parts from metals or plastics. It also covers the modifying of crops to make them easier to grow and better in food quality.
Nuclear Biology — the study of the effects of radioactivity on living things. It is also called Radiation Biology.
Space Biology — the study of the survival problems of living things in outer space.
Exobiology — one of the newest sciences, which considers the possibility of life elsewhere in the universe.
Genomics — the study of whole genomes rather than of individual genes. The genome is the entire DNA sequence of an organism.
Bioinformatics — the management and analysis of biological information stored in databases.
Biometrics — the verification of a person’s identity from body features such as fingerprints, the pattern of the iris in the eye, and behavioural characteristics.

The last three belong together. Once a genome is read, it becomes an enormous quantity of information, and information on that scale cannot be handled on paper — which is why biology now needs computing as much as it needs microscopes.

Real-World Application

Making Insulin In Bacteria People with type 1 diabetes cannot make insulin, the substance that controls the level of glucose in the blood, and must receive it from outside. For many years it was extracted in small quantities from the pancreas of cattle and pigs. Biotechnology changed that. The human gene for insulin is placed inside bacteria, which are then grown in large tanks; as they multiply, they make human insulin, which is purified and used as medicine. The supply is now large, steady and identical to the body’s own.

Side Note

The First Cloned Mammal In 1996, at the Roslin Institute near Edinburgh, a lamb was born that had no father. She was grown from a single udder cell taken from an adult sheep, and was named Dolly. She was the first mammal cloned from an adult body cell.

Do Not Mix Up

Genetics And Genomics Genetics follows single genes and the characteristics they carry from parents to offspring. Genomics studies the organism’s entire DNA sequence at once, gene by gene together.

1.5 How The Study Of Biology Helps Us

A subject earns its place partly by what it explains and partly by what it allows us to do. Biology does both, and its usefulness reaches into ordinary life at several points.

Appreciating The Living World

The world of plants and animals is so vast and so varied that anyone who looks at it closely is left wondering.

Yet biology does something more interesting than cataloguing that variety. It shows that underneath it lies a basic unity. However different a mango tree, an earthworm and you may look, all three are built of cells, all three take in food, release energy from it and reproduce their own kind.

Keeping People Healthy

Biology has explained the causes of many diseases. Before that explanation existed, illness could only be endured; now it can often be prevented.

It has also shown how germs travel from one body to another. Some are carried by insects, some by wind, some by water. Knowing the route is what makes prevention possible — a disease carried by water is stopped in a different way from one carried by a mosquito.

This knowledge is why people today take reasonable care of their health and, on average, live longer than their great-grandparents did.

Try Yourself

Walk once around your school or neighbourhood and note every place where water has been standing for several days — a discarded tyre, a pot, a blocked drain. Mosquitoes breed in still water. Work out which of these could be emptied, and which would need repair.

Conserving Natural Resources

Biology has made clear how completely plants and animals depend on one another. Remove one kind of organism and others that fed on it, sheltered in it or were pollinated by it are affected in turn.

Because of this understanding, both people and governments have come to recognise the dangers of cutting down forests and of killing wild animals indiscriminately. The same science argues for careful use of the petroleum, coal and metal deposits of our planet, which cannot be replaced once used.

Zoom In / Out

Where Conservation Acts Zoom in and you see one organism surviving or dying. Zoom out one step and you see a population, whose numbers rise or fall. Zoom out again and you see an ecosystem, where losing one population changes the rest. Conservation works at these upper levels.

Growing More Food

New varieties of crop plants and new breeds of cattle and poultry are being developed using the knowledge of biology.

Biology has also increased what we know about the diseases of plants and animals, and about how to cure them. A crop saved from disease adds to the harvest as surely as a better seed does.

Together these efforts produce more food in our fields, our dairies and our poultry farms.

Real-World Application

Wheat That Did Not Fall Over Older wheat plants were tall, and when they were given plenty of fertiliser the heavy ears made them bend and fall to the ground, ruining the crop. From the 1960s, dwarf wheat varieties with short, strong stems were bred and introduced into India, along with matching methods of irrigation and fertiliser use. The short plants carried heavy ears without falling, and India’s wheat production rose several times over within about two decades. A change in the shape of a plant, worked out by biologists, altered the country’s food supply.

Curiosity Corner

Q5. How can knowing biology help a farmer grow more food, or a city keep its people healthy?

A. The farmer gains better crop varieties and better breeds of animals, and the means to recognise and treat their diseases. The city gains an understanding of how germs spread through water, air and insects, which is what sanitation, safe water supply and public health measures are built on.

Being A Conscious Citizen

Biology helps in solving the everyday problems of a community — sanitation, public health and water supply among them.

It also gives citizens the facts they need on two larger questions. The first is the growth of human population. A larger population needs more food, more water, more housing and more fuel, and biology is what allows those demands to be estimated. How a society should respond is a matter on which people hold different views, and those views are argued out in public debate rather than settled in a laboratory.

The second is pollution, the addition of harmful substances to air, water or soil. Rising population, industry and transport all add to it, and the heavy use of insecticides in fields, farms and godowns adds further hazards to health. Biology helps us recognise such pollution, measure it and take steps against it.

Careers Built On Biology

Biology is also a basic requirement for a large number of professions.

A student of biology may go on to become a doctor, a dentist, a bacteriologist, a pathologist, a druggist, an entomologist, a forester, a teacher, a veterinary doctor or a biotechnologist, among many others.

What these occupations share is that each of them acts on living things — and acting on a living thing safely requires understanding it first.

1.6 Summary

Science is an organised body of knowledge about the natural phenomena of the material universe, supported by observation and experimentation.
Observation records nature as it is; an experiment deliberately changes one factor and records what follows.
Science has three major branches: Physics, Chemistry and Biology.
Biology is the study of living beings — all plants and animals, including humans. The word comes from the Greek bios, life, and logos, study.
The term life sciences is often used today, because attention has shifted from describing organisms to understanding life processes.
Biology began as the practical knowledge of early humans, who watched plants and animals in order to gather and hunt. Prehistoric cave drawings of animals are evidence of that interest.
Settled farming and the domestication of animals such as the dog, cow, sheep, horse and buffalo allowed living things to be observed steadily, and biology advanced.
The Greeks were the pioneers of an organised study of biology.
Aristotle (384–322 BCE) first studied animals in detail and is called the Father of Biology and the Father of Zoology.
Theophrastus (370–285 BCE) studied plants and is called the Father of Botany.
Hippocrates (c. 460 – c. 370 BCE) sought natural causes for disease and is called the Father of Medicine.
Biology flourished in ancient India between about 2500 BCE and 650 BCE, where animals were classified as Jeevaj, the viviparous animals that give birth to young, and Andaj, the oviparous animals that lay eggs.
Rice was among the earliest crops cultivated in India, and a very large number of varieties were developed here.
The invention of the microscope in the sixteenth century revealed a world of minute organisms, and the compound microscope showed that living bodies are built of cells.
In the nineteenth century biology took three major leaps: the discovery of germs, the wider acceptance of the theory of organic evolution, and the establishment of the cell theory.
Twenty-first century biology works on vitamins, hormones, genetics, genetic engineering, antibiotics, cancer research, cloning, stem cell research, organ transplant, environmental sciences and life in outer space, and is attempting to build the simplest cell-like systems from fatty acids and nucleotides.
Biology is divided into branches in at least three ways: by the major kind of organism, by a special group of organisms, and by the approach of study.
By major kind of organism: botany, zoology and human biology.
By special group of organisms: bacteriology, virology, mycology, phycology or algology, entomology, ichthyology, herpetology and ornithology.
By approach of study: anatomy, morphology, histology, cytology, physiology, embryology, taxonomy (also called systematics), ecology, biogeography, palaeontology, evolution, genetics, parasitology, pathology, immunology, eugenics and biochemistry.
Cytology, histology and anatomy study the same body at three different levels — cell, tissue and organ.
Applied biology puts this knowledge to work in agriculture, apiculture, veterinary science, marine biology, household biology, horticulture, sericulture and pisciculture.
It also works through newer, technology-based fields: molecular biology, biotechnology, cloning, bioengineering, nuclear biology, space biology, exobiology, genomics, bioinformatics and biometrics.
The study of biology helps us appreciate the unity beneath the variety of life, keep people healthy, conserve natural resources, grow more food, act as conscious citizens on questions of sanitation, population and pollution, and enter a wide range of careers.

Flowchart

FC 1.3 — The Shape Of The Subject Science → Biology, the study of living beings → divided by kind of organism (botany, zoology, human biology) / by special group (bacteriology, entomology, ornithology and others) / by approach (anatomy, physiology, genetics, ecology and others) → applied biology, where the knowledge is put to use (agriculture, biotechnology, genomics and others) → benefits to people: health, food, conservation, informed citizenship and careers

1.7 Key Terms

Agriculture — the raising of crops and livestock.
Algology — another name for phycology, the study of algae.
Anatomy — the study of the gross structure of organs, as seen in dissection.
Apiculture — the keeping of bees for honey and beeswax.
Bacteriology — the study of bacteria.
Biochemistry — the study of the chemicals and chemical reactions inside living things.
Bioengineering — the making of artificial body parts from metals or plastics, and the modifying of crops for easier growth and better quality.
Biogeography — the study of the geographical distribution of plants and animals.
Bioinformatics — the management and analysis of biological information stored in databases.
Biology — the study of living beings; from the Greek bios, life, and logos, study.
Biometrics — the verification of a person’s identity from body features such as fingerprints and the iris pattern.
Biotechnology — the use of living cells or microorganisms in industry and technology.
Botany — the study of plants.
Cell — the tiny unit of which every living body is built.
Cell theory — the statement that all living organisms are made of cells and that every cell arises from a pre-existing cell.
Cloning — the production of genetically identical individuals of an organism.
Cytology — the study of the structure and function of animal and plant cells.
Ecology — the study of the relationship of an organism to its living and non-living environment.
Embryology — the study of the formation and development of the embryo.
Entomology — the study of insects.
Eugenics — the idea of improving the inherited qualities of a human population by controlling who has children; rejected today on ethical and scientific grounds.
Evolution — the branch of biology dealing with the origin and descent of organisms.
Exobiology — the science that considers the possibility of life elsewhere in the universe.
Genetics — the science of the transmission of body characteristics from parents to offspring.
Genome — the entire DNA sequence of an organism.
Genomics — the study of whole genomes rather than of individual genes.
Herpetology — the study of reptiles such as lizards and snakes.
Histology — the study of the minute structures of the body at the tissue level.
Horticulture — the science and art of growing fruits, vegetables, flowers and ornamental plants.
Household biology — the study of the animals and insects living in our houses, and of preventing the damage they cause.
Human biology — the study of the human being as a living organism and of its relationship with other organisms.
Ichthyology — the study of fishes.
Immunology — the science of immunity, that is, of resistance to and defence against disease.
Life sciences — the term often used today for biology, emphasising the study of life processes.
Marine biology — the study of life in the sea.
Molecular biology — the interpretation of biological events in terms of the molecules in the cell.
Morphology — the study and interpretation of the form and structure of plants and animals, external and internal.
Mycology — the study of fungi.
Nuclear biology — the study of the effects of radioactivity on living things; also called radiation biology.
Organic evolution — the theory that species living today have descended, with change, from earlier species.
Ornithology — the study of birds.
Oviparous — laying eggs from which the young later hatch; called Andaj in ancient Indian classification.
Palaeontology — the study of prehistoric life through fossils.
Parasitology — the study of organisms that live on or inside other organisms and take nourishment from them.
Pathology — the study of the diseases of plants and animals.
Phycology — the study of algae.
Physiology — the study of the functions and activities of organisms and their parts.
Pisciculture — the technique of growing fish.
Pollution — the addition of harmful substances to air, water or soil.
Science — an organised body of knowledge about natural phenomena, built on observation and experimentation.
Sericulture — the technique of producing silk by raising silkworms.
Space biology — the study of the survival problems of living things in outer space.
Systematics — another name for taxonomy.
Taxonomy — the science of naming, grouping and classifying plants and animals.
Veterinary science — the treatment and surgery of animals.
Virology — the study of viruses.
Viviparous — giving birth to living young; called Jeevaj in ancient Indian classification.
Zoology — the study of animals.

1.8 Points To Ponder

Early humans knew a great deal about the plants and animals around them, yet we do not call that knowledge science. What would have had to change for it to become science?
Aristotle grouped animals without ever seeing a cell, and his groupings were often sound. What does this suggest about how much of biology can be learnt from careful looking alone, and where looking alone must stop?
Cytology, histology and anatomy study the same body at three different levels. Is any one of these levels the ‘real’ one, or does each answer a question the others cannot?
Biology is divided into branches so that a person can study one part deeply. What might a specialist miss that someone looking at the whole organism would notice?
Exobiology looks for life elsewhere in the universe, but every organism we have ever studied is from one planet. How would you decide whether something found on another world was alive at all?
Biotechnology can now alter the genetic material of a crop or a microorganism. Who should decide which alterations are made, and on what grounds?

1.9 Objective Questions

Choose the correct option: (1 mark each)
1. The study of the tissue level of the body with the help of a compound microscope is called:
  1. cytology
  2. histology
  3. morphology
  4. anatomy
2. The scientist called the ‘Father of Botany’ is:
  1. Hippocrates
  2. Aristotle
  3. Theophrastus
  4. Robert Hooke
3. In ancient Indian classification, animals that lay eggs were placed in the group:
  1. Jeevaj
  2. Andaj
  3. viviparous
  4. ectoparasite
4. The technique of producing silk by raising silkworms is:
  1. apiculture
  2. pisciculture
  3. horticulture
  4. sericulture
5. The entire DNA sequence of an organism is its:
  1. genome
  2. embryo
  3. fossil
  4. tissue
6. A parasite that lives inside the body of its host is called:
  1. an ectoparasite
  2. an endoparasite
  3. a pathogen
  4. a host
Each question below gives an assertion (A) and a reason (R). Choose from: (1 mark each)

Both A and R are true, and R is the correct explanation of A.
Both A and R are true, but R is not the correct explanation of A.
A is true but R is false.
A is false but R is true.
1. Assertion (A): Biology advanced once human beings began farming and keeping animals. Reason (R): An animal kept beside a household can be watched every day, through birth, illness and breeding.
2. Assertion (A): The same branch of biology can be applied to a bird and to a fern. Reason (R): Branches such as anatomy and genetics are defined by the approach of study, not by the organism studied.

Match the branch in Column A with the subject of its study in Column B: (5 marks) | Column A | Column B | |—|—| | a. Ornithology | i. Fossils of plants and animals | | b. Palaeontology | ii. Diseases of plants and animals | | c. Immunology | iii. Birds | | d. Pathology | iv. Naming and classifying organisms | | e. Taxonomy | v. Defence of the body against disease |
Fill in the blanks: (1 mark each)
1. The Greek word ______ means life.
2. The study of the relationship of an organism with its biotic and abiotic environment is called ______.
3. Taxonomy is also known as ______.
4. Nuclear biology is also called ______ biology.
State whether each statement is true or false: (1 mark each)
1. Morphology deals only with the external parts of an organism.
2. The compound microscope uses a single lens.
3. Exobiology considers the possibility of life elsewhere in the universe.
4. Biology, Physics and Chemistry are the three major branches of science.
Name the following: (1 mark each)
1. The branch of biology that studies the formation and development of the embryo.
2. The applied field concerned with keeping bees.
3. The theory that all organisms are made of cells and that every cell arises from a pre-existing cell.
4. The branch that studies the geographical distribution of plants and animals.
5. The scientist called the Father of Medicine.
Pick the odd one out in each set and give a reason for your choice: (2 marks each)
1. Mycology, virology, entomology, physiology
2. Agriculture, horticulture, pisciculture, palaeontology
3. Aristotle, Theophrastus, Hippocrates, Robert Hooke

1.10 Check Your Concepts

Define science, and state the two activities on which it rests. (2 marks)
Give the meaning of the word ‘biology’ from its Greek roots. (2 marks)
Name any four branches of biology that are based on a special group of organisms, and state what each studies. (2 marks)
Give a reason: settled farming and the domestication of animals helped biology to advance. (3 marks)
Differentiate between the following pairs, stating the basis of difference in each case: (3 marks each)
1. Observation and experiment
2. Viviparous and oviparous animals
3. Ectoparasite and endoparasite
Why do scientists today often prefer the term ‘life sciences’ to the term ‘biology’? (3 marks)
Explain, with one example each, how cytology, histology and anatomy study the same body at different levels. (4 marks)
State the three major leaps taken by biology in the nineteenth century, and explain briefly what each of them established. (4 marks)
What would happen to the study of biology if the microscope had never been invented? Give three consequences. (4 marks)
Describe five ways in which the study of biology helps human beings in everyday life. (5 marks)

1.11 Figure-Based Questions

Study Fig. 1.0-1. (4 marks)
1. Name the instrument shown.
2. How many lenses does it use, and what does this make it — a simple or a compound instrument?
3. State the purpose of the pointed pin placed in front of the lens.
4. Name one kind of organism that such an instrument first revealed to human beings.
Fig. 1.2-1 shows drawings made on cave walls in prehistoric times. (3 marks)
1. Identify the two animals drawn.
2. What do such drawings tell us about the interest of early human beings?
3. Which branch of biology today studies prehistoric forms of life?
Refer to Fig. 1.3-1. (4 marks)
1. Name the branch shown studying fossils, and the branch shown studying inheritance.
2. State one function of the branch labelled physiology.
3. Why are all these branches drawn as arising from a single trunk?
Look at the four panels of Fig. 1.4-1. (4 marks)
1. Name the applied field represented in each panel.
2. Redraw the panel showing silkworms, and label the mulberry leaf, the larva and the cocoon.