172) The “25 Euro Silver-Niobium
Coin Series: (Part xii): 2003 onwards minted by the Austrian Mint by using Niobium
and Niobium metal insertion technology for the first time anywhere in the World
of Numismatics: The Twelfth coin in the Series: “Evolution” (2014):
The theme of this coin is
Evolution and it illustrates the story of the development of Homo sapiens from
other species.
The concept of human
evolution, is as old as Charles Darwin’s “On the Origin of Species” (published
in 1859), or perhaps even older in a nascent way.
Several mechanisms have
led to the understanding of human evolution, which has been facilitated by
electron microscopes, carbon dating of fossils and remains of ancient man etc.
One of the most fruitful
methods to learn about human antecedents is to observe living animals that
resemble man’s direct ancestors.
Among these distant cousins of man are tree
shrews, which were primitive animals not very different from the earliest
mammals. Another one is the coelacanth, a rare fish descended from the
ancestors that had inside their fleshy fins, bone connections uncannily like
the bones of human arms and legs. On limbs much like these, the first
invertebrates crawled up onto the land.
Today, even animals
distant from man can reveal insights into his past. In particular, much about
ancient behaviour is deduced from studies of modern animal behaviour. Man is a
social animal, for example, who was not the first to find strength in numbers.
Several types of insects did so many millions of years ago, and the result was
the wonderful world of the social insects – ants, bees, wasps, termites etc. –
whose civilised colonies can be found in every habitable part of the World. Although
the insects provided none of man’s heritage, their group living offers illuminating
parallels to his own societies.
Similar parallels can be
found in the tightly structured group living of such animals as wolves and
baboons. However, none of these low-level societies of mammals, show signs of
progressing to a higher level. This feat, which literally changed the face of
the Earth, was accomplished by erect-walking primates who were the
direct ancestors of man. Their hunting groups, which at first were like wolf
packs, gradually became more tightly organised. Their descendants developed
speech for quick and accurate communication. They learnt how to use fire and
fashion weapons of wood, stone or bone. They built shelters to protect
themselves from inclement weather and acquired clothing that enabled them to
live comfortably in cold climates.
Thereafter, the history of
man is largely that of his technical advances and social achievements. Perhaps,
the greatest achievement was the almost simultaneous development of agriculture
and animal husbandry. When the first farmers had acquired domesticated plants
and animals, they turned unproductive land into cultivated fields and pastures.
Human population increased enormously and pushed into areas inhabited thinly by
wandering hunters. Villages appeared, acquired walls and fortifications,
followed by cities, countries and empires. In not more than 1.3 million years –
a miniscule period of time on the evolutionary scale – from the appearance of
the first creature that could be called human, mankind has changed from a
scarce and wandering hunter race to being the undisputed lords of planet Earth.
Man
dominates the animal kingdom not only because he possesses a big brain capable
of rational thought, but also some physical traits of overwhelming significance
- a skeleton built for walking upright, eyes capable of sharp, three
dimensional vision in colour and hands that provide both a powerful grip and
nimble manipulations.
A
Timeline of Life’s evolution:
·
Our solar system is thought to have formed
from a giant rotating cloud of gas and dust known as a proto-planetary disc
some 4.67 billion years ago. The sun
formed at the centre of the disc and the planets gradually formed around the
Sun in a process called accretion. The Earth’s moon formed as a result of a
collision between Earth and a Mars sized body called “Theia”. The impact caused
a portion of the combined mantle of earth and Theia to be expelled into space,
eventually forming the Moon.
·
It
is believed that the Earth thereafter went through a violent period of
near-constant collisions with large asteroids and comets. From fossil evidence, it appears that life existed on Earth some 3.5
billion years ago.
·
Around this time, one-third of planet Earth
consisted of a gigantic continent, covered with rocks, mountain ranges ragged
trenches and patches of bright minerals across stony plains. The cooling of the
Earth allowed for crust formation and the condensation of water present in the
atmosphere formed the Earth’s oceans which rolled over two-thirds of the
planet. Almost everywhere volcanic cones and fissures spouted dust and vapour
or gushed crimson rivers of lava that hardened into black rocks/mountains. The
climate, uniformly tropical and humid, was marked by local fogs, clouds, rain
and lightning storms. Winds and waves scoured and ploughed the land. The sea was empty of life and the land shows no traces of green or life.
There was no breathable free oxygen in the atmosphere, which consisted mainly
of water vapour, hydrogen and two poisonous gases, ammonia and methane which dissolved
and bubbled in the waters of the sea and land.
·
Ultraviolet radiation, which was inimical
to life, fell upon the planet from the Sun. In such an environment, none of the
higher forms of life that would later populate the Earth could have survived. Nevertheless, within the hostile environment
of primitive Earth were the very prerequisites for the creation of life which
came in three stages, each stage transforming the Earth to bring forth the
World that men will eventually inhabit.
·
For 1000 million years, since the birth of
the planet, the physical constituents of life – carbon, hydrogen, oxygen and
nitrogen, the basic ingredients of organic substances making up all living
things – had been accumulating in the atmosphere and the waters. There was also electricity in the lightning
that ripped through the sky, radiation, in the UV light, heat from the volcanoes
etc. which would act as a catalyst for the “creation” of life. In the warm primal sea, true life was
about to emerge which will remain in the sea for more than 2000 million years
constantly changing in form and function.
·
Gradually, the primitive Earth’s energy and
raw materials began to generate the stuff of which life is made – notably the
organic compounds called amino acids, which are the building blocks of proteins
and also of DNA, the carrier of hereditary patterns for all living things. The
sea became rich in these materials and the primitive sea now contained what is
termed as a “kind of organic soup”. As
yet there was no sign of life. Then the natural forces made some of the
available materials join together into new and still more complex substances
some of which had a surprising capacity to reproduce themselves and proliferate
– these were the first living organisms
on earth. They were microscopic and
resembled modern viruses, bacteria and fungi.
·
As there was no free oxygen to breathe, these
organisms got the energy to sustain themselves by breaking down the materials
of the organic soup, through a chemical action called fermentation which is
still employed by many bacteria and fungi.
However, these living forms by continuously feeding upon the organic
soup would have exhausted the organic soup itself. This was a fatal flaw that sent the Earth’s original life forms down an
evolutionary dead-end, because these life forms were consuming and destroying
the very conditions needed for their own survival.
·
About 3000 million years ago, life got a fresh impetus on Earth.
A major waste product of fermentation is carbon dioxide – which became the
starting point for new forms of life containing the substance chlorophyll.
Chlorophyll made possible the process called “photosynthesis” which converted
carbon dioxide, water and sunlight into sugar, which then became food for
chlorophyll containing forms of life. These
forms, freed from dependence upon the ready-made molecules of the organic soup,
flourished in great numbers, slowly evolving into all the varied members of the
plant kingdom. These, in turn, produced another opportunity for life on
Earth.
·
Photosynthesis, like fermentation, has a
waste product – oxygen – which over a period of 1000 million years penetrated
the waters in which the first plants grew.
The evolution of photosynthesis, allowed cyano-bacteria to convert light
energy to chemical energy. The formation
of oxygen molecules as a by-product of photosynthesis eventually transformed
the Earth’s atmosphere and paved the way for bio-diversity on the planet.
The oxygen was lethal to many of the early fermenting organisms, but took
another 1000 million years to accumulate in the atmosphere, and paved the way
for different, more efficient forms of life. Almost 1000 million years ago,
certain microscopic forms began to sustain themselves by combining oxygen with
living material – from plants or from other forms like themselves.
·
These oxygen breathing animals, the
earliest ancestors of man, soon swarmed in the sea, feeding upon plants and
upon one another. From minute one-celled blobs, they developed in a fairly
short time into highly specialised creatures. Some were mobile and could propel
themselves through the water with tiny, whip-like tails, others floated
passively or anchored themselves to undersea slopes. Eventually they became
sponges, jelly-fish, worms and coral.
·
Some
of the microscopic blue-green algae, the
first plants to evolved, trapped bits of sediment and layer by layer, built
up huge structures called stromatolites which still exist today. We know little
about these first organisms.
·
The above illustration shows
successive layers of microbes and sediment result in the striated pattern of
growth, which stands like upside-down ice-cream cones which were produced by
the activity of sheets of blue-green algae (cyanobacteria) trapping and binding
sediment in layers, stand on a Precambrian sea floor around 1000 million years ago.
Stromatolites like these grew as tall as 50 feet, but their odd shapes –rock
formations, striated patterns of growth were determined by an as yet
inexplicable process.
These
stromatolites still present today are hardened sediment once bound by
now-decayed blue-green algae, some 2000 million years ago.
·
Recent
studies of stromatolite samples suggest that microbes may have existed on Earth
as early as 3.5 billion years ago. Some other samples have confirmed that
microbial life has been dated back definitely to 2.7 billion years ago. This
indicates that life evolved on Earth sometime during Earth’s tumultuous first
billion years.
·
Geological evidence suggests that life on
Earth was limited to prokaryotic bacteria like life until around 2
billion years ago, which lacked a discrete nucleus (prokaryote is Greek for
“before nucleus”). Modern eukaryotes (eukaryote is Greek for “true
nucleus”) are characterised as having membrane bound organelles, such as mitochondria
and chloroplasts, as well as a membrane bound nucleus. It is believed that the
organelles and nucleus may have evolved as a result of an ancient symbiotic
relationship between different bacteria. Eventually, the bacteria that went on
to become organelles transferred the bulk of their genetic information to the
host cell genome and lost their ability to survive independently.
·
Around 1.2 billion years ago,
multi-cellularity is believed to have evolved several times in the history of
life on Earth. According to a scientific thought, multi-cellularity evolved as
a result of a symbiotic relationship between cells of the same or different
species, eventually leading to interdependency.
·
The
fossil record from the Cambrian period i.e. around 500 to 600 million years
shows a sharp increase in the diversity and number of complex animals during a
relatively short time span in Earth’s history.
The cause of the Cambrian Explosion is unknown, although it is believed that
the rise in atmospheric oxygen or other environmental changes may have played a
significant role.
·
For over 150 million years (225 to 70
million years), dinosaurs populated the Earth, eventually reaching every
continent on the Earth. Their sudden mass extinction known as the
Cretaceous-Tertiary Extinction Event is thought to have been caused by a large
asteroid impact or an increase in volcanic activity eventually leaving the
planet for another form of life to emerge, evolve and rule the planet – Man!!
The
Geological Time Chart:
GEOLOGICAL ERA
|
PERIOD
|
EPOCH
|
DATE
|
BIOLOGICAL FEATURES
|
CAINOZOIC
|
Quarternary
|
Pleistocene
|
10000
to 2 million
|
First
True man: Homo erectus*
|
Tertiary
|
Pliocene
|
2
to 10 million
|
First
man-like apes
|
|
Miocene
|
10
to 25 million
|
|||
Oligocene
|
25
to 40 million
|
First
monkeys and apes
|
||
Eocene
|
40
to 60 million
|
|||
Palaeocene
|
60
to 70 million
|
First
primates : prosimians
|
||
MESOZOIC
|
Cretaceous
|
70
to 135 million
|
First
flowering plants and Last Dinosaurs
|
|
Jurassic
|
135
to 180 million
|
First
birds
|
||
Triassic
|
180
to 225 million
|
First
mammals, First Dinosaurs
|
||
PALAEOZOIC
|
Permian
|
225
to 270 million
|
||
Carboniferous
|
270
to 350 million
|
First
coniferous trees, first reptiles and First insects
|
||
Devonian
|
350
to 400 million
|
First
forests, first amphibians and first bony fish
|
||
Silurian
|
400
to 440 million
|
First
land plants, first fish with jaws
|
||
Ordovician
|
440
to 500 million
|
First
vertebrates: Armoured fish without jaws
|
||
Cambrian
|
500
to 600 million
|
Invertebrate
fossils: first shell-bearing animals
|
||
PRECAMBRIAN
|
600
to 4500+
Million
|
First
Living Things: Algae & Bacteria
|
*"Modern man' is called Homo
sapiens sapiens (in Latin) which only means “intelligent man”. The oldest known fossils found in Asia & Africa are about 40000 years old.
Palaeozoic means “ancient
life”, Mesozoic means “middle life” & Cainozoic means “recent life” in
Greek.
Evolution
from soups to cells – the complex building blocks of life & Process of
Natural Selection:
Living things, even
ancient organisms like bacteria are very complex. All this complexity did not
spring fully-formed from the primordial soup. Instead, life originated in a
series of small steps, each building upon the complexity that evolved
previously.
·
Simple
organic molecules, similar to nucleotides: These were formed
as the building blocks of life at the origin of life. The organic molecules
were synthesized in the atmosphere of early Earth and rained down into the
oceans. RNA and DNA molecules – the genetic material for all life – are simply
long chains of nucleotides.
·
Replicating
molecules evolved and began to undergo natural selection:
All living things reproduce, copying their genetic material and passing it on
to their off-spring. Thus, the ability to copy the molecules that encode
genetic information is a key step in the origin of life, without which life
would not exist. This ability probably first evolved in the form of an RNA
self-replicator – an RNA molecule that could copy itself. Self-replication
opened the door for natural selection. Once a self-replicating molecule formed,
some variants of these early replicators would have done a better job of
copying themselves than others, producing more “off-springs”. These super-replicators would have become
more common – i.e. until one of them was accidentally built in a way that
allowed it to be a super-super-replicator – after which this variant would take
over. Through this process of continuous natural selection, small changes in
replicating molecules eventually accumulated until a stable, efficient
replicating system evolved. This development in the broader perspective led to
the continuous extinction/near extinction of several species.
·
Replicating
molecules became enclosed within a cell membrane:
The evolution of a membrane surrounding the genetic material provided two
advantages: the products of the genetic material could be kept close by and the
internal environment of this proto-cell could be different from the external
environment. Cell membranes encased
replicators quickly out-competed “naked” replicators.
·
Some
cells began to evolve modern metabolic processes and out-competed those with
older forms of metabolism: Upto this point living
organisms relied on RNA for most jobs, however, this changed when some cells
evolved to use different types of molecules for different functions: DNA (which is more stable than RNA) became
the genetic material, proteins (which are often more efficient promoters of
chemical reactions than RNA) became responsible for basic metabolic reactions
in the cell and RNA was demoted to the role of a messenger, carrying
information from the DNA to protein-building centres in the cell. Cells
incorporating these innovations easily out-competed “old-fashioned” cells with
RNA based metabolisms.
·
Multicellularity
evolution: Around 2 billion years ago, some cells
stopped going their separate ways after replicating and evolved specialised
functions. They gave rise to Earth’s
first lineage of multicellular organisms, such as red algae etc.
The
evolution of the spine:
From the simple structure
in a pre-historic fish to a complex instrument in modern man, the spine has
evolved to support body and head and to aid intricate movements:
An
undifferentiated spinal column served the eusthenopteron, which was an early
bony fish of 375 million years ago.
Its similarly shaped
vertebrae, joined to short ribs, gave swimming muscles something to pull
against. The uniform ribs along eusthenopteron’s spine lent only a lateral
undulating movement.
Its vertebrae, as a
consequence, were more solidly constructed. Its large ribs helped it to hold up
its head on land as well as supporting its body.
The
vertebrae of the mammal-like reptile thrinaxodon, even more closely locked
together than those of ichthyostega and had specialised shapes and sizes.
For example, the vertebrae were large near the
limbs and smaller in the lighter tail. Thrinaxodon’s neck ribs had shrunk, thus
enabling it to move its head far more easily than ichthyostega.
A
modern tree shrew that resembles extinct primitive mammals is capable of moving
along the ground as well as climbing trees, arching and extending its backbone
as it moves.
Its vertebrae are designed
for both types of movements. The tree shrew’s highly flexible neck is partly
due to the shrinkage of neck ribs, now mere vestigial bumps.
The
ancient primate mesopithecus, although a quadruped, was capable of briefly
supporting its body on its rear legs while reaching and grasping, and its
backbone was accordingly specialised – rigid when upright but flexible enough
to allow it to travel through trees.
Its vertebrae had acquired
a variety of shapes. The small cervical or neck vertebrae permitted head
movement while supporting the skull either vertically or horizontally. The
large vertebrae in the lumbar region of the lower back supported propulsive
movement. Mesopithecus’ head movement depended partly on the “atlas-axis
complex” of two neck vertebrae. The top one enabled the head to move up and
down and is therefore called the “yes” bone. The axis, which is just below gave
sideways head movement, hence it is called the “no” bone.
To
provide support for man’s upright, biped posture, the vertebrae of his spine
are strongly locked together in a flexible, vertical rod.
The vertebrae are
increasingly heavy from the top, down to the hips, where the weight of the body
is transmitted to the legs. The backbone must not only be strong enough to bear
most of the weight, but has to be flexible enough to enable man to balance on
two legs. Nevertheless, man’s vertebrae are separated by easily damaged discs
and back trouble is a common complaint.
Man’s upright posture has
also given him a head position that in relation to his spine is different from
the position of the heads of semi-erect primates. The top of the spine has
migrated from its position in the back of the skull, to a point almost directly
under the skull. Thus man’s head is neatly balanced at the top of his fully
erect spine and there it stays as he freely moves his ribless neck.
Deoxyribonucleic
acid (or DNA):
The structure of the DNA was
discovered in 1953 by Francis Crick and James Watson, who were awarded the
Nobel Prize in 1962 in Physiology or Medicine for
their work leading to this discovery.
Deoxyribonucleic acid,
commonly known as DNA is a code for life/ hereditary material found in almost
every living organism. It is found in strands known as chromosomes in
the interior part of a cell – the nucleus. Nearly every cell in a person’s body
has the same DNA. Most DNA is located in the cell nucleus (where it is called
nuclear DNA), but a small amount of DNA can also be found in the mitochondria
(where it is called mitochondrial DNA or mtDNA).
Each chromosome contains genes
which are blue- prints of
genetic information and are made up of segments of DNA. DNA also contains the
blueprints for making proteins and for replicating itself.
The DNA molecule is a double
helix, resembling a spiral/twisted ladder. The sides of the ladder are made
up by alternating units of phosphate and a sugar, deoxyribose. Attached to the
sugar units are rungs of the ladder, which are made up of combinations of
bases. The information in DNA is stored as a code made up of four chemical
bases: adenine (A), guanine (G), cytosine (C) and thymine (T). Human DNA
consists of about 3 billion bases and more than 99% of these bases are in all
persons. The order or sequence of these bases determines the information
available for building and maintaining an organism, similar to the way in which
letters of the alphabet appear in a certain order to form words and sentences.
DNA bases pair up with
each other, A with T and C with G to form units called base pairs. Each base is
also attached to a sugar molecule and a phosphate molecule. Together, a base,
sugar and phosphate are called a nucleotide. Because of chemical attractions,
only a few combinations of bases are possible for ex: A – T, T – A, C – G, or G
– C. Length-wise, up and down the ladder, the bases form different patterns,
for example: ATCGAT. Three of these bases together form a codon which
encodes a single amino acid of a protein. The order of the bases in one
strand (half) of the ladder determines the order of the bases in the other
strand. For example, if the bases in one strand are ATCGAT, then the bases in
the opposite strand will be TAGCTA.
An important property of
DNA is that it can replicate, or make copies of itself. Each strand of DNA in
the double helix can serve as a pattern for duplicating the sequence of bases.
This is critical when cells divide because each new cell needs to have an exact
copy of the DNA present in the old cell.
Before a cell divides, the
DNA duplicates itself. The ladder splits length-wise, separating the bases of
each strand. Then, with the help of special enzymes, the bases in each half
ladder pick up their matching counterparts. The As attach to Ts, the Ts to As,
the Gs to Cs and the Cs to Gs. In this way each new ladder becomes a duplicate
of the original ladder. When the cell divides, the two new cells have identical
DNA molecules.
DNA also determines the
proteins a cell makes. It does this by encoding a messenger ribonucleic acid
(mRNA) with information needed to make proteins in “cell factories” called ribosomes
in the cytoplasm of a cell. The amino acid structure of each protein made by a
ribosome corresponds to a particular sequence of bases in the DNA.
DNA molecules, found in
chromosomes in the nucleus of every cell, carry the genetic information that
determines inherited traits, such as skin colour, hair colour and body
function. This information dictates the formation of proteins used by the body
for growth and chemical processes.
If
there is a mistake made during DNA replication and a sequence is altered (known
as mutation), the composition of a protein may also be changed. The result may
be a genetic disorder. There are over 4200 diseases which are known to be
caused by genetic defects.
The
Human Genome Project has
mapped the entire genetic code of DNA.
This amazing scientific achievement holds out the promise of an
understanding of, and possibly a cure for, inherited disorders.
Chromosomes:
A chromosome is a
thread-like structure in the nucleus of a cell. Every chromosome consists of a
double strand of DNA, arranged in a helical shape. Each chromosome contains
many hundreds of genes.
The nucleus of every cell
in the normal human body contains 46 chromosomes arranged as 23 pairs. The
exceptions are ova (eggs) and sperm cells which have only 23 single
chromosomes. One pair of the 23 pairs of chromosomes is the sex chromosomes. In
males, one of the two sex chromosomes is shorter and contains fewer genes than
the other – it is the Y chromosome. The other, longer, sex chromosome is the X
chromosome. Males have an X and a Y chromosome, while females have two X
chromosomes.
Some
chromosome related abnormalities can be red-green colour and night blindness.
Chromosomal abnormalities may arise through mutation of chromosomes or may be
inherited. Some abnormalities are compatible with life, though usually the
affected person may have physical or metabolic abnormalities which may be
severe.
Genes:
These are units of genetic information, passed from parent to off-spring and
are found on chromosomes in the nucleus of each cell. Humans have 3 pairs of
chromosomes and at conception, each parent contributes one chromosome of each
pair. These chromosomes are then copied into each cell in the body. Chromosomes
consist of DNA, with each gene being a section of DNA that instructs the cell
how to make a particular protein.
The instruction is
contained in the order or sequence of nucleotide bases (adenine, guanine,
cytosine and thymine) of the DNA which codes the sequence of amino acids in the
protein.
Humans
have approximately 100,000 genes, with each person having different
combinations giving them their unique characteristics. Not all genes are active
at any one time; gene expression can be inhibited or induced, depending on the
function of the cell and the body’s needs.
Because
each person has a unique genetic make-up, DNA analysis (DNA fingerprinting) can
be used to identify individuals as in forensic medicine. Since we inherit half
of our genes from each parent, the DNA of close family members contains more
similarities than that of unrelated people.
Passing
on genetic information: DNA, containing genetic information,
is found within the nucleus of the cell. It is transcribed to mRNA within the
nucleolus of the cell. The genetic information is then translated by ribosomes
in the endoplasmic reticulum, into a sequence of amino acids which form
a protein. The proteins are then incorporated by the Golgi apparatus into small
packets (vesicles) and released at the cell membrane.
Gene
sequencing: Each nucleotide base interlocks with a
specific partner to form a base pair. Three base pairs form a codon and code
for one amino acid. The order in which the bases are carried on a DNA strand
determines the information contained in that strand.
Genetic
code: Genetic information is contained in the myriad
combinations of bases that exist along the length of the DNA molecule. A gene
is a particular sequence of bases which codes for a specific protein. Proteins
catalyse chemical reactions, build cells and tissues and ultimately confer
characteristics on an individual. Even a single base alteration can lead to a
disease.
Heredity:
Heredity is the genetic
transmission of biological traits from one generation to the next. Millions of
traits, ranging from eye colour and facial features to information the body
needs to develop organs and tissues are transmitted through heredity.
Heredity operates through structures
in the nucleus of the cell known as chromosomes of which there are 46 in
humans. The chromosomes carry thousands of DNA units called genes, which
contain the hereditary code. These codes cover physiological, biochemical and
physiological traits of a person. For example, some genes govern the
development of tissues and organs. Others govern certain traits such as
straight or curly hair, colour vision and blood type. The expression of some
traits in the new individual depends on how the parent’s genes interact. Some
genes are dominant, while others are recessive.
The presence of one or two
dominant genes results in expression of the dominant gene, for example, the
gene for brown eyes in humans is dominant over the gene for blue eyes. To
exhibit a recessive trait, such as blue eyes, both genes, one from each parent
must be recessive.
Many characteristics are
influenced by more than one gene. Skin colour, for example is controlled by
several genes. Some characteristics depend on other inputs besides the genes.
For example, although intelligence may be genetically influenced, it is also
determined by environmental influences.
Sex-linked traits refer to
those hereditary traits that are carried on the X chromosome, such as colour
blindness. Genetic defects passed on by heredity
from one generation to another are the cause of many human diseases and
disorders many of which have been identified. Many genes that cause diseases
have now been identified, allowing parents the option of genetic counselling
and testing during pregnancy. Advances in DNA mapping and bionics, hold out the
promise of eliminating or curing many hereditary diseases at a future date.
Ribonucleic
acid (RNA):
Ribonucleic acid (RNA) is one of the three
major biological macromolecules that are essential for all known forms of life
(along with DNA and proteins). The flow of genetic information in a cell takes
place from DNA through RNA to the proteins. RNA,
thus, are the work-horses of the cell and play leading roles in the cell as
enzymes, structural composition, cell signalling etc.
DNA is considered the
“blueprint” of the cell, which carries all the genetic information required for
the cell to grow, take in nutrients and to propagate. RNA, in this role is the
“DNA photocopy” of the cell. When the cell needs to produce a certain protein,
it activates the protein’s gene – the portion of the DNA that codes for that
protein – and produces multiple copies of that piece of DNA in the form of
messenger RNA (mRNA). The multiple copies of mRNA are then used to translate
the genetic code into protein through the action of the cell’s protein
manufacturing machinery called the “ribosomes”.
Thus, RNA expands the quantity of a given protein that can be made at
one time from one given gene, and it provides an important control point for
regulating when and how much protein gets made.
Recent
researches have revealed that RNA plays a more important role than was hitherto
believed which was acting as a DNA photocopy (mRNA) and a genetic coupler
between the genetic code and protein building blocks (tRNA), as well as, a
structural component of ribosomes (rRNA). In recent years, however, it has been
found that RNA can also act as enzymes, called “ribozymes” to speed up chemical
reactions.
In
several clinically important viruses, RNA, rather than DNA, carries the viral
genetic information as was found in ancient early forms of life on Earth. RNA
also plays an important role in regulating cellular processes – from cell
division, differentiation and growth to cell aging and death. Defects in
certain RNAs or the regulation of RNAs have led to several important human
diseases, including heart diseases, cancer, etc.
Present
Day:
For a million years or
more, man’s evolution has been independent of his surroundings and his
adaptability to any environment – even the hostile vacuum of space seems
assured. However, today, he is ready to tip the balance of evolution and
environment in a different way. He is now able to interfere directly with the
processes established by his own evolution. He has acquired the ability to
change the genetic inheritance/coding which make humans what they are. However,
he needs to tread this path cautiously so as not to lead to regressive/harmful
mutations and side-effects beyond his control.
The 25 Euro
Silver-Niobium coin titled “Evolution”:
This
path-blazing Silver-Niobium Coin is the most innovative coin in this Series. For
the first time, two colours/shades of Niobium have been used on this coin–blue & green.
On the Obverse of the Coin, symbolising
the origin of Evolution as a whole, an image of the DNA molecule, (the double
helix), also known as Deoxyribonucleic
Acid, is depicted as well as RNA (Ribonucleic acid) – both of which are
the keys and fundamental to evolution. Also shown on this face of the coin is a half-filled
beaker, with the liquid contained therein bubbling, a microscope for studying
samples on slides and a symbol of the Caduceus, which is symbolic of Medicine.
On the outer periphery is
mentioned on top the name of the country “REPUBLIK
OSTERREICH” (meaning, the “Republic of Austria”) and the year of issue
“2014”. On the left periphery is mentioned the denomination of the coin “25
EURO” and on the lower to right periphery is mentioned the theme of the coin
“EVOLUTION”.
On the Reverse of the Coin is depicted
the history of human development and the diversity of life-forms brought about
by evolution. On the outer silver ring starting from the bottom periphery
clock-wise is depicted a DNA Double Helix. The DNA chain represents life itself
which has diversified into a bird, the brightly coloured toucan represents life
forms and their abundance in the air. The fish and the frog represent life in
water and how life evolved into land-based creatures. The mushrooms, and a flower
whorl are representative of a complex biological world which has evolved over
the eons along with the plants and animals. The leaves represent trees and
plants, vital to replenishing the oxygen content in the atmosphere through the
process of photosynthesis, and a fish both of which are partially overlapping
into the Niobium core/pill and a frog, representing amphibious life (both on
land & water). In the inner Niobium core is shown the evolutionary cycle of
the Homo Sapiens – the first Monkeys and Apes (who evolved during the Cainozoic
Era, in the Tertiary Period in the Oligocene Epoch, 25 to 40 million years ago)
to the first man-like Apes (who appeared in the Cainozoic Era in the Tertiary
Period in the Pliocene Epoch, 2 to 10 million years ago) to the First true man,
the Homo Erectus (who appeared in the Cainozoic Era in the Quarternary Period,
Pleistocene Epoch, 10000 to 2 million years ago). Of course, the man depicted
on this coin is well groomed & is like a 10.0 version of his ancestors. Air
bubbles surround these elements, representing the key role played by oxygen in
sustaining life.
Links:
1) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: First Coin: "700 Years of Hall City in Tirol or Tyrol"
2) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Second Coin: "150 Years of Semmering Alpine Railway"
3) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Third Coin: "50 Years of Television in Austria"
4) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Fourth Coin: "European Satellite Navigation System"
5) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Fifth Coin: "Austrian Aviators"
6) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Sixth Coin "Fascinating Light"
7) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Seventh Coin: " The International Year of Astronomy"
8) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Eighth Coin: "Renewable Energy"
9) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Ninth Coin: "Robotics"
10) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Tenth Coin: "Bionics"
11) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Eleventh Coin: "Tunnel Construction"
12) The 50 Euro Gold Coin Series: Klimt and his Women: 2012-2016 (includes Coin of the Year 2015 (COTY)
For posts on COTY (Coin of the Year) winners since 2015 in a competition held by Krause Publications of Germany, please visit the following links:
Links:
1) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: First Coin: "700 Years of Hall City in Tirol or Tyrol"
2) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Second Coin: "150 Years of Semmering Alpine Railway"
3) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Third Coin: "50 Years of Television in Austria"
4) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Fourth Coin: "European Satellite Navigation System"
5) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Fifth Coin: "Austrian Aviators"
6) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Sixth Coin "Fascinating Light"
7) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Seventh Coin: " The International Year of Astronomy"
8) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Eighth Coin: "Renewable Energy"
9) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Ninth Coin: "Robotics"
10) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Tenth Coin: "Bionics"
11) The 25 Euro Silver-Niobium Coin Series issued by the Austrian Mint: Eleventh Coin: "Tunnel Construction"
12) The 50 Euro Gold Coin Series: Klimt and his Women: 2012-2016 (includes Coin of the Year 2015 (COTY)
Links to posts on Federal Republic of Germany issues and other posts on this blog:
For posts on COTY (Coin of the Year) winners since 2015 in a competition held by Krause Publications of Germany, please visit the following links: