WHAT IS BIOLOGY
Biology (bios [life] + logy) is:
the science of life or living matter in all its forms and phenomena,
especially with reference to origin, growth, reproduction, structure
and behaviour.
a science that deals with things that are alive (such as plants and
animals)
Biology is the study of life and living organisms, from one-celled
creatures to the most complex living organism of all — the human
being. Biology includes the study of genes and cells that give living
things their special characteristics
In more detail:
“Biology is a science that examines the evolutional history of living
beings, their structures - from one-celled creatures to the most
complex living organism – their life-sustaining activities, their
behaviors, relationships and interactions both with each other and
also with the environment and also their capabilities”.
BRANCHES OF BIOLOGY
Living beings are divided into two big groups as Plant Kingdom
(Regnum Vegetabile) and Animal Kingdom (Regnum Animale). The
branch of science examining the Animal Kingdom is called Zoology
and the branch of science examining the Plant Kingdom is called
Phytology (Botany).
These two important and big branches of biology are divided into
sub-branches to examine the plants and animals in respect to morphology,
anatomy, cytology, histology, embryology, ecology, genetics, physiology
and systematics. Common sub-branches of Botany and Zoology are as
follows:
1. Morphology (morph [form] + logy): Examines the living beings in
respect to their structures. It also has some sub-branches:
a) Cytology (cyto [cell] + logy): The science dealing with cells.
Examines the microscopic structures of cells.
b) Histology (histo [tissue] + ology): The science dealing with tissues.
Examines the microscopic structures of tissues.
c) Anatomy (ana [up] + tome [to cut]): Macroscopically examines the
visible internal and external properties of an organism.
d) Organography: The science
dealing with organs. Examines
the structure of the organs of
living beings.
e) Embryology (embryo + logy):
Examines the embryological
developments starting from the
formation of a zygote to the
formation of an independent
living being.
2. Physiology (physio [nature] 4 logy): It is the science of the normal
function of living things. Examines the activities of vitality and functions
of the organs and organ systems.
For example:
- Metabolism (nutritional) physiology
- Growth physiology
- Physiology of motion etc.
3. Molecular Biology: Examines the structure of genes (structures
containing the genetic materials) and the biological events occuring
under the control of the genes (e.g. metabolic events such as protein
synthesis, hormone synthesis etc.) at the molecular level.
4.Genetics: Examines inheritance of genetic characters from generation
to generation, the fundamentals of genetics and genetic disorders.
5. Evolution: Examines the changes and the origins of these changes that living
being has gone through from their simplest form to their current status as
individuals and as population.
6. Systematics (Taxonomy (taxis [arrangement] + nomia [method]): Deals
with the classification of living beings.
7. Pathology (patho [suffering - disease] + logy): Examines the diseases and abnormal
structures of the organism.
8. Microbiology (micro [small] + logy): Examines microscopic living beings like viruses, rickettsia,
bacteria and protozoa.
9. Ecology (oikos [house] + logy): Examines the relationships of living beings with the
environment that they live in.
10. Sociology (social + logy): Examines the social lives of living beings.
11.Paleontology (Archeobiology): The science of fossils. Examines the living
beings that had lived in the geological periods and became extinct with the
help of their remnants (fossils).
12.Teratobiology (Teratology): Morphologically examines a living being that
has formed with a genetic defect; it also examines the reasons of the
formation of this defect and the methods of prevention.
Immunobiology (Immunological Biology): Examines the ability of an
organism to recognize the causes of diseases and to resist them,
it also deals with the prevention of the disease.
Plant: Autotrophic living beings made up of one or more cells. They have a
cellulosic cell wall.
Animal: They are living beings made up of one or more cells just like plants,
however they are heterotrophic organisms. They move actively. Their cells are
only surrounded with a cytoplasmic membrane, they lack the cellulosic membrane
called cell wall.
Species: A group of living beings that are biologically and morphologically similar
to each other, producing fertile offspring when they mate with each other and
can pass their genetic characters from generation to generation.
It is also the basic unit in taxonomy.
COMMON AND TYPICAL CHARACTERS OF LIVING
BEINGS
Living beings can be differentiated from non-living
beings with the following properties:
1. Individualism: All living beings have specific shapes that never change. E.g. when we
think about a human, a cat, a bird, a tulip etc., the image (shape) that we conjure up in our
minds are distinct and specific.
2. Structural properties: Though external appearances of living beings vary from each
other, they are similar to each other in respect to their internal structures.
For example:
All living beings are made up of cells.
In general, a vital fluid called cytoplasm and a nucleus is present in every cell.
All living cells are made up of carbohydrates, proteins, lipids, nucleic acids, enzymes and
vitamins.
3. Physiological properties: Physiological events taking place in living beings
are also similar to each other.
Anabolism: Substances taken from outside and assimilated are converted
to the substances that are found within the structure of the living beings
like carbohydrates, lipids and proteins that have high molecular weights
ad energies when burned.
Catabolism: Big molecules found in the body (foodstuff) re burned with
oxygen and disintegrated into smaller molecules. Vital tasks are
performed during this process with the help of the arising energy.
4. Growth: Living beings have the ability to grow from the inside. Addition
of new tissues to the existing ones can only be accomplished with internal
growth. However non-living beings do not grow from the inside, however
their sizes might increase due to bulking of additional materials on them.
5. Irritation: It is the ability of a living being to react to an internal or
external influence. For example: Stayinq away from danger, the need to
eat something when we are hungry, a plant’s turning to a light source. If
living beings had lacked this ability, then they would have a less of
survival.
6. Reproduction and genetics: All living beings that have grown to a certain in
its life have the ability to produce another similar living being that. This is
accomplished by some cells or gonads. Offsprings inherit various
characteristics of their parents.
7. Adaptation: All living beings adapt to their environments.
8. Death (Ex): Living beings that lose the aforementioned characteristics
die eventually.
