THE BIOLOGY

Chapter # 01

Theory & Question Answers
Section I - Introduction

THE BIOLOGY

BIOLOGY:
Biology is the study of life and living organisms, defined as "the branch of natural science that deals with organisms and different phenomenon of life." Formerly, living organisms were classified into two kingdoms, i.e., plant kingdom and animal kingdom.

SUBDIVISION OF BIOLOGY:

• Botany:
  Botany is the subdivision of biology that deals with the scientific study of plants.

• Zoology:
  Zoology is the subdivision of biology that deals with the scientific study of animals.

Five Kingdom System:
According to the modern system of taxonomy, living organisms have been classified into the following five kingdoms.

• Kingdom Prokaryotae (Monera):
  It includes almost all the prokaryotes, e.g., bacteria and cyanobacteria.

• Kingdom Protictista (Protista):
  It includes all the unicellular eukaryotic organisms, which are no longer classified as animals, plants, or fungi, e.g., Euglena, Paramecium, Chlamydomonas, Plasmodium, etc. Multicellular algae and primitive fungi have also been included.

• Kingdom Fungi:
  It includes non-chlorophyllous, multicellular (except yeast) organisms having chitinous cell walls and a coenocytic body called mycelium, e.g., Agaricus (mushroom), yeast, etc. They are absorptive heterotrophs.

• Kingdom Plantae:
  It includes all the eukaryotic, multicellular, chlorophyllous, photosynthetic autotrophs with cell walls made primarily of cellulose, zygote retained to become an embryo, and exhibiting heteromorphic alternation of generations, e.g., Moss, Fern, Pines, Apples, etc.

• Kingdom Animalia:
  It includes all eukaryotic, non-chlorophyllous, multicellular, ingestive heterotrophs with no cell wall, e.g., Hydra, Earthworm, Human beings, etc.

Scientists have discovered and named more than one and a half million species of living organisms which exist in a great variety of forms - shapes and sizes. For example, the smallest microscopic ones, bacteria which may measure no more than 0.0001 mm to probably the largest animal, whale, in the world, which may measure up to 40 meters in length and weigh 150 tons and trees, redwood tree, measuring over 300 feet in height.

Modern biology does not only concern with the recognition and classification of these species but also deals with their vital structural and functional aspects.

MAJOR BRANCHES OR FIELDS & SPECIALIZATION IN BIOLOGY:
Some of the major branches or fields of specialization in biology are defined below.

• Molecular Biology:
  It is a recent branch of biological science that deals with the structure and function of the molecules which form the structure of the cell and its organelles that take part in the biological process of a living organism (Nucleic acids – Protein molecule).

• Microbiology: (Micro = Very Small)
  It deals with the study of microorganisms (viruses, bacteria, protozoans, and pathogenic fungi), which can only be seen under a microscope.

• Environmental Biology:
  It deals with the study of environment and its effects on organisms. Previously it was known as ecology.

• Marine Biology:
  It deals with the study of organisms inhabiting the sea and ocean, and the physical and chemical characteristics of their environment.

• Fresh Water Biology:
  It deals with the life dwelling in freshwater bodies, their physical and chemical characteristics affecting it.

• Parasitology: (Para = Beside, Sitos = Foode, Logs = Science/Study)
  It deals with the study of parasitic organisms, their life cycles, mode of transmission, and interaction with their hosts.

• Human Biology:
  This branch of biology deals with all biological aspects of man regarding evolution, anatomy, physiology, health, inheritance, etc.

• Social Biology: (Sociare = Companion)
  Social biology is concerned with the social interactions within a population of a given animal species, especially in human beings, focuses on such issues as whether certain behavior is inherited or culturally induced.

Biotechnology: (Bio = life, Technologia = systematic treatment)
This is a very recent branch introduced in biological sciences. It deals with the use of the data and techniques of engineering and technology for the study and solution of problems concerning living organisms, particularly human beings.

LEVELS OF BIOLOGICAL ORGANIZATION:
Life is built on a chemical foundation. This foundation is based on elements. Atom is the smallest possible unit of an element, which retains all the properties of that element.

• Molecules:
  Atoms may combine in a specific way to form molecules.

• Organic Molecules:
  The molecules of living matter containing carbon as a basic element bonded covalently with a hydrogen atom. The simple organic molecules are sugar, glycerol, fatty acids, amino acids, purine, and pyrimidines.

• Macromolecules:
  In the bodies of living organisms, simple organic molecules are converted into more complex organic molecules called macromolecules and recognized as nutrients carbohydrates, lipids, and proteins.

• Cell:
  By various chemical arrangements and formulation of complex molecules, life emerges on the level of a cell. A cell is the smallest unit of life. All cells contain genes, which are functional units of DNA. Inside the cell, sub-cellular structures called organelles are present.

• Tissues:
  The cellular fabric of many varieties, of which organisms are made, is a cell tissue group of cells that perform a particular function, e.g., nervous tissues, xylem, etc.

• Organ:
  Various tissue types combine to make up an organ, e.g., the brain.

• Organ System:
  Several organs that collectively perform a single function form an organ system, e.g., the nervous system consists of the brain, spinal cord, sense organs, and nerves.

• Individual Whole Organism:
  Different organ systems functioning altogether in a highly advanced coordination and cooperation make up an individual whole organism.

Biotechnology: (Bio = life, Technologia = systematic treatment)
This is a very recent branch introduced in biological sciences. It deals with the use of the data and techniques of engineering and technology for the study and solution of problems concerning living organisms, particularly human beings.

LEVELS OF BIOLOGICAL ORGANIZATION:
Life is built on a chemical foundation. This foundation is based on elements. Atom is the smallest possible unit of an element, which retains all the properties of that element.

• Molecules:
  Atoms may combine in a specific way to form molecules.

• Organic Molecules:
  The molecules of living matter containing carbon as a basic element bonded covalently with a hydrogen atom. The simple organic molecules are sugar, glycerol, fatty acids, amino acids, purine, and pyrimidines.

• Macromolecules:
  In the bodies of living organisms, simple organic molecules are converted into more complex organic molecules called macromolecules and recognized as nutrients carbohydrates, lipids, and proteins.

• Cell:
  By various chemical arrangements and formulation of complex molecules, life emerges on the level of a cell. A cell is the smallest unit of life. All cells contain genes, which are functional units of DNA. Inside the cell, sub-cellular structures called organelles are present.

• Tissues:
  The cellular fabric of many varieties, of which organisms are made, is a cell tissue group of cells that perform a particular function, e.g., nervous tissues, xylem, etc.

• Organ:
  Various tissue types combine to make up an organ, e.g., the brain.

• Organ System:
  Several organs that collectively perform a single function form an organ system, e.g., the nervous system consists of the brain, spinal cord, sense organs, and nerves.

• Individual Whole Organism:
  Different organ systems functioning altogether in a highly advanced coordination and cooperation make up an individual whole organism.

BROADER LEVEL OF ORGANIZATION:
A group of very similar interbreeding organisms which produce fertile and viable offspring. The members of a species have the same number of chromosomes. It is the basic unit of biological classification.

Population:
Members of the same species living in close association in a given area are considered a population.

Community:
Two or more populations of different species living and interacting in the same area.

Ecosystem:
A community with its environment, including land, water, and atmosphere, constitutes an ecosystem. A community together with its non-living surroundings.

Biosphere:
The entire surface region of the earth inhabited by living things is called the biosphere.

Phyletic lineage:
It’s an ancestor to descendant link which shows the common origin of species.

BIOLOGICAL METHODS:
A scientific method which is used to resolve a biological problem related to or produced by living organisms is called a biological method.

Steps Of Biological Methods:
It consists of the following steps:

• Observation:
  Scientists make keen observations and collect the facts already reported by other scientists.

• Hypothesis:
  Intelligent guess in the form of a statement on the basis of observed facts or available information is called hypothesis. This part involves inductive reasoning where scientists use isolated facts to reach a general idea that explains a phenomenon.

• Deductive Reasoning:
  The logical test or logical explanation of the hypothesis is called deduction. A deduction is a statement which further leads to an experiment, and it often involves "if" and "then."

• Experiment:
  Practicals are conducted to test the hypothesis. It is based on deduction.

• Conclusions:
  Based on the results of accurate experimentation, conclusions are drawn. The conclusion either proves or rejects the hypothesis.

THEORY:
If more and more evidence comes to hand in the favor of a hypothesis, the hypothesis gains acceptance and eventually is promoted to the rank of a theory. A theory is a set of scientific assumptions consistent with one another and supported by evidence.

LAW:
If a theory is found to be true in all tested circumstances, it is accepted as a law.

APPLICATIONS OF BIOLOGY FOR THE WELFARE OF MANKIND:
Biology has made an enormous impact on human welfare and in improving quality of life. The practical contribution of biology creates importance among the people. Knowledge of biology ensures a higher standard of living and helps us:

• To promote better health.
• Protection and conservation of the environment.
• In the field of agriculture and medical science.

IMMUNIZATION BY VACCINATION:
Vaccination involves the inoculation of a pathogen in an inactive form in hosts’ bodies to induce immunity in the host. It was first introduced by Edward Jenner in 1795. Vaccination enhances and produces immunity against the various pathogens in the body process called immunization. In the vaccination process, vaccines are introduced in animals and humans to prevent them from infectious diseases such as Polio, Smallpox, and Hepatitis, etc. Vaccine reduces the children's mortality rate.

ANTIBIOTICS:
These are the chemical substances produced by some microorganisms which are in low concentration inhibit the growth or even kill other microorganisms. The first antibiotic to be discovered was penicillin. It was derived from the fungus Penicillium notatum. Fleming, Florey, and Chain received the Nobel Prize jointly in 1945 for this path-breaking discovery. The antibiotics used to control critical diseases like T.B, Leprosy, Typhoid, Cholera, and Anthrax.

RADIOTHERAPY:
Another achievement of biological research is radioactive rays (X – rays) has been used in the medical sciences for the diagnosis and treatment of human diseases. In recent medical technology, radioactive rays are successfully used to treat cancer or tumors; ultrasonic or shock waves are used to cure kidney stones. In advanced medical science, biologists are busy developing new medicines to tackle the problem related to health. These days treatment of diseases that previously uncovered with the help of certain chemical substances has proved to be successful, e.g. some anticarcinogenic chemicals are given to cancer patients.

HYDROPONICS:
It is an effective agricultural technique to tackle the problem of food deficiency and produce better quality crops. Hydroponics is the science of growing terrestrial plants in an aerated solution. It is also known as soilless or water culture. Hydroponics is basically a cultivation through micronutrients.

Advantages:

• It controls weeds and soil disease problems.
• It requires a very small area for cultivation.
• Plants can be grown in arid areas.
• It is used to determine which of the mineral elements are essential.

CLONING:
It is the production of identical duplicate copies of genetic material; either cell or organ or entire multicellular organism. A duplicate copy is known as a clone.

Types of Cloning:

Natural Cloning:
It occurs naturally in plants and animals. Some common examples include identical twins or triplets in humans, asexual reproduction in plants and animals, regeneration, and the development of tumors and cancers.

Artificial Cloning:
Artificial cloning has long been a focus of attention in biological sciences. The first cloned mammal was Dolly, a sheep, successfully developed in 1997.

Advantages:
Cloning of human cells such as liver cells, skin cells, and blood cells has been very promising for transplantation. Vegetative reproduction of fruits and nuts by grafting helps to overcome food shortages. Through this technology, the production of medically significant substances such as insulin, growth hormones, interferon, and anti-thrombin has been achieved.

PROTECTION AND CONSERVATION OF ENVIRONMENT:
Our environment faces a great threat from pollution. Acid rain, stone cancer, and greenhouse effects have increased with the rise in human population and industrialization. Many toxic wastes produced by industries, deforestation, and industrialization have disturbed the balance of nature with catastrophic results. The study of biology provides the knowledge to maintain a stable and balanced ecosystem, to conserve and protect our environment by growing plants, and reduce pollution from industries.

CONCEPT OF BIOLOGICAL CONTROL AND INTEGRATED DISEASE MANAGEMENT:
In disease management, the use of natural processes to combat pathogens is very helpful. It involves the following methods:

Introduction of Natural Enemies:
Biological pest control involves exposing them to parasites and predation. If small fishes are introduced in ponds and ditches of stagnant water, they feed on mosquito larvae. Thus, malaria is controlled naturally.

Inter Planting:
Growing plants in climates that are unstable for the pathogen can control plant diseases. Interplanting stimulates conditions in the natural ecosystem by limiting the spread of infectious diseases and can also control.

Crop Rotation:
It involves the cultivation of different crops alternatively in the same field. It doesn’t only avoid the risk of the same pathogen in the next year, but also controls the growth of parasitic weeds.