Biology
History
The term biology is derived from the Greek word ,
bios, "life" and the suffix -, -logia, "study of." The
Biology deals with the study of the many living
organisms (clockwise from top-left) E. coli, tree fern,
gazelle, Goliath beetle
Latin form of the term first appeared in 1736 when
Linnaeus (Carl von Linn) used biologi in his Bibliotheca
botanica.
Biology is a natural science concerned with the study of
life and living organisms, including their structure,
Energy
function, growth, evolution, distribution, and taxonomy
Modern biology is a vast and eclectic field, composed of
many branches and subdisciplines. However, despite
the broad scope of biology, there are certain general and
The survival of a living organism depends on the
continuous input of energy. Chemical reactions that are
responsible for its structure and function are tuned to
unifying concepts within it that govern all study and
extract energy from substances that act as its food and
research, consolidating it into single, coherent fields. In
transform them to help form new cells and sustain them.
general, biology recognizes the cell as the basic unit of
In this process, molecules of chemical substances that
life, genes as the basic unit of heredity, and evolution as
the engine that propels the synthesis and creation of
constitute food play two roles; first, they contain energy
that can be transformed for biological chemical
new species. It is also understood today that all
reactions; second, they develop new molecular
organisms survive by consuming and transforming
structures made up of biomolecules.
energy and by regulating their internal environment to
The organisms responsible for the introduction of energy
maintain a stable and vital condition.
into an ecosystem are known as producers or
Subdisciplines of biology are defined by the scale at
autotrophs. Nearly all of these organisms originally draw
which organisms are studied, the kinds of organisms
energy from the sun. 35 Plants and other phototrophs
studied, and the methods used to study them:
use solar energy via a process known as photosynthesis
Biochemistry examines the rudimentary chemistry of life; to convert raw materials into organic molecules, such as
ATP, whose bonds can be broken to release energy. 36
molecular biology studies the complex interactions
among biological molecules; botany studies the biology
A few ecosystems, however, depend entirely on energy
of plants; cellular biology examines the basic building-
extracted by chemotrophs from methane, sulfides, or
block of all life, the cell; physiology examines the
other non-luminal energy sources. 37
physical and chemical functions of tissues, organs, and
Some of the captured energy is used to produce
organ systems of an organism; evolutionary biology
biomass to sustain life and provide energy for growth
examines the processes that produced the diversity of
and development. The majority of the rest of this energy
life; and ecology examines how organisms interact in
is lost as heat and waste molecules.
their environment.
Fields dealing with animals:
Comparative anatomy ( ) The scientific study of similarities and differences in the bodily structures of
distinct types of animals.
Entomology ( ) The study of insects.
Ethology ( ) The study of animal behavior.
Herpetology ( ) The study of reptiles and amphibians.
Ichthyology ( ) The study of fish.
Mammalogy ( ) The study of mammals.
Ornithology ( ) The study of birds.
Primatology ( ) The study of primates.
Veterinary science ( ) Animal medicine.
Zoology ( ) The study of animals.
Branches of biology relevant to the study of evolution:
Biogeography ( ) The study of the geographic distributions of living organisms.
Developmental biology The study of the processes by which an organism changes from a single cell into
a mature, multicellular individual.
Evolutionary biology The branch of biology concerned with the modes of origin of new forms of life.
Ichnology ( ) The scientific study of the fossilized traces of past animal activity, such as footprints,
burrows, trails, and borings.
Morphology ( ) The branch of biology concerned with the form and structure of living organisms.
Paleontology ( ) The study of prehistoric life by means of fossils.
Fields relating to the environment:
Astrobiology ( ) The branch of biology concerned with the effects of outer space on living organisms and
with the search for extraterrestrial life.
Bioclimatology ( ) The study of the influence of climate on living organisms.
Chronobiology ( ) The study of time-dependent phenomena in living organisms.
Conservation biology The branches of biology concerned with habitat preservation, the prevention of
extinction, and conservation of biodiversity.
Cryobiology ( ) The study of the effects of low temperatures on living organisms.
Ecology ( ) The study of the interaction of organisms with each other and with their environment.
Geobiology ( ) A science that combines geology and biology to study the interactions of organisms with
their environment.
Limnology ( ) The study of the physical and biological conditions of freshwater, particularly of lakes and
ponds.
Chemistry-based branches of biology:
Biochemistry ( ) The study of life at the chemical level, in particular the chemistry of proteins,
carbohydrates, and nucleic acids.
Bioengineering ( ) A hybrid field of scientific research that uses the principles of biology and the
techniques of engineering to produce useful products.
Molecular biology The branch of biology that studies the formation, structure, and function of
macromolecules found in living organisms, particularly nucleic acids and proteins.
