Though we all know what is life, it is a challenge for scientists and
philosophers to define life in unequivocal terms. This is
difficult partly because life is a process, not a pure substance. Any definition of life must be sufficiently broad to
encompass all life with which we are familiar, and must be
sufficiently general to include life that may be fundamentally
different from life on Earth.
– Seven characteristics of life
“We biologists have a
working definition: 'something organic that can obtain energy,
independently reproduce and have the ability to adapt to its
environment.'” FSU Biology
Professor Dr. Scott Fritz.
Life is considered a characteristic of organisms that exhibit all or most
of the following characteristics or traits:
Regulation of the internal environment to maintain a constant
state; for example, electrolyte concentration or sweating to
Being structurally composed of one or more cells — the basic
units of life.
Transformation of energy by converting chemicals and energy into
cellular components (anabolism) and decomposing organic matter
(catabolism). Living things require energy to maintain internal
organization (homeostasis) and to produce the other phenomena
associated with life.
Maintenance of a higher rate of anabolism than catabolism. A
growing organism increases in size in all of its parts, rather
than simply accumulating matter.
The ability to change over time in response to the environment.
This ability is fundamental to the process of evolution and is
determined by the organism's heredity, diet, and external factors.
to stimuli: A response can take many forms, from the contraction
of a unicellular organism to external chemicals, to complex
reactions involving all the senses of multi cellular organisms. A
response is often expressed by motion; for example, the leaves of
a plant turning toward the sun (phototropism), and chemo taxis.
The ability to produce new individual organisms, either asexually
from a single parent organism, or sexually from two parent
These complex processes, called physiological functions, have underlying
physical and chemical bases, as well as signaling and control
mechanisms that are essential to maintaining life.
gives this interesting list
7 Characteristics of Life:
1. Living Things are composed of Cells:
organisms have everything they need to be self-sufficient.
multi-cellular organisms, specialization increases until some
cells do only certain things.
Living Things Have Different Levels
molecular and cellular organization.
things must be able to organize simple substances into complex
things organize cells at several levels:
a group of cells that perform a common function.
Organ - a group of tissues that perform a common function.
system - a group of organs that perform a common function.
Organism - any complete living thing.
3. Living Things Use Energy:
things take in energy and use it for maintenance and growth
4. Living Things Respond To Their Environment:
things will make changes in response to a stimulus in their
behavior is a complex set of responses.
Living Things Grow:
division - the orderly formation of new cells.
enlargement - the increase in size of a cell. Cells grow to a
certain size and then divide.
organism gets larger as the number of its cells increases.
6. Living Things Reproduce:
is not essential for the survival of individual organisms, but
must occur for a species to survive.
living things reproduce in one of the following ways:
reproduction - Producing offspring without the use of
reproduction - Producing offspring by the joining of sex
7. Living Things Adapt To Their Environment:
are traits giving an organism an advantage in a certain
of individuals is important for a healthy species.
With each new technological
breakthrough things get more complicated. Microscopes become
successively more powerful, able to penetrate the depths of body,
cell and nucleus, revealing new life, different life,
unclassifiable by common convention.
Lewis structure of a carbon atom, showing its four valence
some unknown reason, Carbon forms the key component for all known
naturally occurring life on Earth. Complex molecules are made up
of carbon bonded with other elements, especially oxygen, hydrogen
and nitrogen, and carbon is able to bond with all of these because
of its four valence electrons. The complex molecules that humans use in their biological processes are
based primarily on chains of carbon atoms (with some other atoms
thrown in). Every biologically active molecule used in the human
body contains carbon somewhere. Other elements used by the human
body include oxygen, nitrogen, hydrogen, sulfur, phosphorus,
sodium, potassium and calcium, but these elements are only
attached to the carbon chains.
is abundant on earth. It is also lightweight and relatively small
in size, making it easier for enzymes to manipulate carbon
molecules. It is often assumed in astrobiology that if life exists
somewhere else in the universe, it will also be carbon based. This
assumption is referred to by critics as carbon chauvinism.
Characteristics of carbon as a basis for life
two most important characteristics of carbon as a basis for the
chemistry of life are that it has four valence bonds and that the
energy required making or breaking a bond is just at an
appropriate level for building molecules which are not only
stable, but also reactive.
fact that carbon atoms bond readily to other carbon atoms allows
for the building of arbitrarily long complex molecules and
are not many other elements which even appear to be promising
candidates for supporting life - for example, processes such as
metabolism - but the most frequently suggested alternative is
silicon. This is in the same group in the Periodic Table of
elements and therefore also has four valence bonds. It also bonds
to itself, but generally in the form of crystal lattices rather
than long chains. Silicon compounds are generally stable but do
not support the ability readily to re-combine in different
permutations in a manner that would plausibly support lifelike
acronym CHNOPS, which stands for carbon, hydrogen, nitrogen,
oxygen, phosphorus, and sulfur, represents the six most important
chemical elements whose covalent combinations make up most
biological molecules on Earth.
Sulfur is used in the amino acids cysteine and methionine. Phosphorus is an essential element in the formation of
phospholipids, a class of lipids that are a major component of all
cell membranes, as they can form lipid bilayers, which keep ions,
proteins, and other molecules where they are needed for cell
function, and prevent them from diffusing into areas where they
should not be. Phospholipids are also an essential component of
things contain DNA
The seven characteristics are simply explanation of what is observed in
all Life forms. However
a better definition of Life is in terms of the DNA codes that are
found in all life forms. Every
living thing has in their cells the instructions, the blueprint of
life. This is the DNA
or deoxyribonucleic acid found in our cell nucleus.
The genetic instructions of all living organisms are
contained in molecules of deoxyribonucleic acid. DNA contains
instructions that are used by cells to produce proteins. The vast
array of different chemical reactions that build and maintain
cells are controlled by proteins.
DNA is made of a series of bases in a specific order.
Cells use DNA to create amino acids which in turn create
proteins, which in turn create cells, which in turn create body
parts over a lot of intermediate steps.
The DNA is double helix shaped, which is a “twisted ladder” shape.
Each rung of the ladder is made of a series of two bases
bonded together. DNA
has four bases called: Adenine, Thymine, Cytosine, Guanine, which
we shorten to A, T, C, G. A always binds to T, C always binds to G.
The way that these bases sit on each rung of the ladder
determine the order they will code for proteins.
The DNA will split apart when it is time to use the DNA for
coding. Each rung of
the ladder is available to bind to other bases called RNA.
The instructions for making proteins are found in the genes;
different genes contain instructions for different proteins or
parts of proteins. Before protein is synthesized, the information
in DNA must first be copied. The copy is composed of a substance
similar to DNA called mRNA (for messenger RNA). It is mRNA that is
used in the manufacture of protein. The diagram below illustrates
that information in DNA is used to create mRNA and that
information in mRNA is used to synthesize protein.
By 1950’s, DNA was pinned down as the genetic blueprint of life.
Stanley Miller was taught that life was produced from
organic compounds under earth's
atmospheric conditions of around 3,800 million years ago
when high voltage electric lightning charges hit
on a mixture of hydrogen,
methane, ammonia and water vapor soup. He tried to reproduce these
conditions. Lo and
behold, there appears - amino acids, commonly called the building
blocks of life. Subsequent experiments in this new field of
“abiotic chemistry” would yield purine and pyrimidine, sugars
which are integral to the structure of both RNA and DNA. Thus we came to the beautiful conclusion that life’s organic
components could be synthesized from an inorganic matter. The
chemical compounds of living things are known as organic compounds
because of their association with organisms. They do not produce
life? How do you go
from organic compounds to organisms with life? How do the
components of life rise up and coalesce into an organism?” The
question is how to jump from matter to life is gulf which science
could not surf.
do these come from?
is the code
Key carbon-based molecules in the life processes are:
most notable groups of chemicals used in the processes of living
which are the building blocks from which the structures of living
organisms are constructed (this includes almost all enzymes, which
catalyses organic chemical reactions)
which carry genetic information
which store energy in a form that can be used by living cells
also store energy, but in a more concentrated form, and which may
be stored for extended periods in the bodies of animals.
is clear, carbon is not the most abundant material in the universe
nor of the surface of earth to form the most probable building
block for life. Yet
it is the basic element that supports life - a low probability
Life Outside of Earth
life, such as bacteria, has been hypothesized to exist in the
Solar System and throughout the universe. This hypothesis relies
on the vast size and consistent physical laws of the observable
universe. According to this argument, made by scientists such as
Carl Sagan and Stephen Hawking, it would be improbable for life
not to exist somewhere other than Earth.
Fermi’s paradox: at lunch one day in 1950, the famous physicist
asked aloud, ‘Where is everybody?’ referring to alien
visitors. Fermi argued that if the Earth is not special in having
intelligent life, then civilizations should already have evolved
many times in our galaxy, since there are billions of stars older
than the Sun. If any one of these civilizations had wanted to
colonize the galaxy, they could have done so by now. Since there
is no compelling evidence that any aliens have visited the Earth,
we must conclude that we are alone.
the other hand, one of the pioneers of the search for
extraterrestrial intelligence, Frank Drake, estimated that there
were probably between 1000 and 100 million advanced civilizations
in our galaxy.
Frank Drake (1930- )
equation, also called Green Bank equation purports to yield the
number N of technically advanced civilizations in the Milky Way
Galaxy as a function of other astronomical, biological, and
psychological factors. Formulated in large part by the U.S.
astrophysicist Frank Drake, it was first discussed in 1961 at a
conference on the “search for extraterrestrial intelligence” (SETI),
held at the National Radio Astronomy Observatory in Green Bank,
W.Va. The equation predicts the number of possible life forms in
The official U.S. government position
on extraterrestrial life, and the three major efforts in the
search for it are:
1. Looking for extra solar planets (Image:
for signals (Image: Allen
the Solar System (Image: Curiosity rover)
The Search for Extra-Terrestrial
Search for Extra-Terrestrial Intelligence (SETI) is based at the
University of California in Berkley and has several radio
telescopes that are dedicated to listening out for signals from
alternative life forms. The researchers need to be dedicated since
despite constant searching after picking up a promising signal in
1977, they haven’t heard anything else.
scientists add to the growing list of planets in the universe
which are classed as habitable, Professor Cockell poses an
important question – Does life always arise whenever a planet's
conditions deem it possible? It should if life evolved whenever
physical conditions are met. Habitable planets may turn out to be
abundant in the universe; however the search for life on them may
yield only negative results.
could mean that:
No life could evolve outside of earth
If they did these never reached a civilization which could
technologically advanced to send out signals to the rest of the
These civilizations which reached a technologically
advanced state, did not survive beyond at least a hundred years
after that. They have
destroyed themselves with atomic and nuclear power.
They were a fallen people and there were no Noah who
survived and continued.
is dangerous to assume life is common across the universe – it
encourages people to think that not finding signs of life is a
"failure" when in fact it would tell us a lot about the
origins of life," added Professor Cockell. In his talk,
Professor Cockell suggests that scientists should use his
hypothesis to avoid the assumption that habitable conditions are
likely to contain life, and as a result, approach the question in
a more scientifically robust and experimentally testable way.”
(Read more at: http://phys.org/news/2013-03-life.html#jCp).
as far as we know, life did not and does not evolve because the
conditions are favorable. Habitable planets may turn out to be abundant in the
universe; however the search for life on them may yield many
negative results. "It is dangerous to assume life is common
across the universe – it encourages people to think that not
finding signs of life is a "failure" when in fact it
would tell us a lot about the origins of life," added
In his talk,
Professor Cockell suggests that scientists should use his
hypothesis to avoid the assumption that habitable conditions are
likely to contain life, and as a result, approach the question in
a more scientifically robust and experimentally testable way.
experiment has produced life from chemicals, and it has never been
observed. Biochemists have not been able to create a single cell or any
simple form of life from raw chemicals even though we have been at
it. Growing awareness
of the extreme complexity of living things at even the smallest
scales led to the formal challenge of Evolution theory by the only
possible alternative which demanded an Intelligent Design by a
Person. From this perspective, no amount of time, even billions of
years, would produce the biosphere by natural causes alone.
Shapiro is a Professor of chemistry and DNA expert at New York
University. A Darwinist, Shapiro calculated the probability of the
2,000 different proteins found in simple bacteria having formed
obtained the following result: 1 in 10^40,000 (a number formed by
4,000 zeros following the number 1; which does not correspond to
anything in the universe). And there are 200,000 different
proteins in the human body! The
chance of the 2,000 proteins in simple bacteria to form
coincidentally is 1 in 1040,000. Since the number of different
proteins in the human body is 200,000, nothing can put this
improbability into perspective.
Wickramasinghe, Professor of Applied Mathematics and Astronomy at
Cardiff University, has this to say about Shapiro’s calculation:
likelihood of the spontaneous formation of life from inanimate
matter is one to a number with 10^40,000 noughts after it…It is
big enough to bury Darwin and the whole theory of evolution. There
was no primeval soup, neither on this planet nor on any other, and
if the beginnings of life were not random, they must therefore
have been the product of purposeful intelligence.””
A Chain of Miracles, Harun Yahya
fact which should strike any scientist is that life does not
evolve because the conditions are favorable for life.
Life is not a potential property of matter.
Life came from dimensions outside of the 11 dimensional
material realms. It penetrates beyond the uncertainty region and
beyond the singularity of creation. Life was given by an
intelligent creator from the dimension of life. ”Thus, in our
view, a ‘proto-conscious’ source of mind is omnipresent in the
universe as OR events which shape reality. However experientially
rich, human-like consciousness required biological evolution of a
mechanism to ‘orchestrate’ Objective Reduction events, and
couple them to brain neuronal activity." S. Hameroff, R.
Penrose / Physics of Life Reviews
at some point in history, the life giving Spirit entered into the
realm of Matter to produce life as we see on earth.
Is it still present in the whole Universe?
Did it create other forms of life in other dimensions which
are beyond matter also? It
did. That is what the
creation, God the Father is the ultimate intelligent Designer (far
beyond any level of intelligence we could ever imagine) of the
universe. Everything was built according to a plan conceived in
His mind. The universe was then spoken into existence by God the
Son - (John 1). The
Word was made flesh in the creation of the material Universe. The
thoughts of God were put into the form of spoken words and from
the words of the Son of God; the creation sprang into existence
and took on form and shape.
universe was empowered, molded and crafted, and inanimate cells
were given life by God the Holy Spirit.
God did not order the universe into existence as a finished and
complete system where there is no future and hope. The
creation involved the cooperative work of all three persons of the
godhead. The Biblical view of God is that of a
"hands-on" creation. God was involved in every step of
the design, fabrication and finishing of the universe, with all
the potential of free independent development and growth. He
remains involved to this day as the Sustainer of everything (Col.
1:16, 17). In the
same tone God involves all his creation to be involved in the
process of growth and future.
creating order from disorder
in Other Dimensions
we are here talking only about the life as we know of based on
Carbon and in Material Realm.
Are there other life forms in non-material realms?
Have anything in common with us here and now?
Can we come in communication with them?
These are not matters usually dealt with in science.
It is taken over by religions, philosophy and mysticism.
All cultures in the world from time immemorial had asserted
such existence of life and called them in generic terms as
co-exist with material world and they do share some dimension with
us to communicate with us. Thus
the cosmos is much bigger than we ever can understand.
What is given in folklores and scriptures form only a
skeleton of the reality.