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					Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)



                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.
In Section 1. we learned that science does not deal in absolute truths but supplies
provisional models which have to be continually altered and improved to accommodate
new information. In this unit we will consider how the general working model that
scientists have used to understand the universe has developed over the last 2500 years.
This general working model is known as a paradigm.


ARISTOTLE'S PARADIGM.
Aristotle was a Greek philosopher who lived about 2,500 years ago.
Like most early views of the universe, his was an earth-centred
one.
He believed that the sun, planets and stars were made of an
eternal substance called quintessence. These moved round the
earth on invisible crystal spheres, each sphere contained within it
the next sphere. Each sphere caused the next sphere to move and
so on. The furthest out sphere which caused all the rest to move
was called the PRIME MOVER.                                                         Aristotle
Aristotle's paradigm did well in explaining much of the behaviour
of the sun and stars but it failed to explain the wandering behaviour of the planets.
Viewed from the earth the planets do not appear to move in a regular way at all but
wander about. Planet means "wanderer". Here was a piece of data that the Aristotelian
paradigm didn't accommodate.




                           THE PTOLEMIC UNIVERSE.
                           500 years later another Greek - Ptolemy offered an explanation
                           of the erratic behaviour of the planets. Like Aristotle, his
                           universe was earth-centred. Ptolemy concluded that the planets
                           moved in epicycles - circles within circles. The picture below
                           shows his theory. This explanation was accepted by astronomers
                           for 1,500 years.



      Ptolemy




J.Keenan                                                             Section 3 Page 1
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


                                      3. Scientific Accounts of the Origin of the Universe
                                                                        The Development of the Big Bang Theory.



                                            o f fixe d s ta
                                   h e re                   rs
                              Sp
                                                                              THE UNIVERSE OF COPERNICUS.
                       rn
                     tu
                    a
                   S


                                              S un

                                             us
                                         Ve n M
                                                e
                                                rc
                                   E a rth       u                  r
                                                r
                                                y                  e
                                      on                          it
                                   Mo                             p
                                                                 u
                                                                 J

                            M
                             a
                              rs




                                                                                               Copernicus.
           Ptolemy's view of the                                              The picture above shows how
           universe.                                                          Ptolemy improved upon
                                                                              Aristotle's view of the
                                                                              Mars           Earth

                                                                              universe by offering an
It was that revolutionary approach of
Nicolaus Copernicus (1473-1543) that led to                                   explanation of the erratic
our present understanding of the universe. In                                 behaviour of the planets.
order to get at the truth scientists often Earth
have to go against what common sense and
intuition dictate - Common sense tells us that
the sun orbits the earth - We see it rising in
                                                        Epicycle
the East, passing overhead at midday then                                 Mars

setting in the West. Copernicus felt that
mathematical discrepancies in the explanation
of the Universe of his time could be remedied by going against common sense and
imagining a sun centred universe. By suggesting that the earth spins on its axis, he
explained day and night and by
                                      3. Scientific Accounts of the Origin of the Universe
                                                                        The Development of the Big Bang Theory.


suggesting that the earth orbits the sun along with the other planets, he gave an


J.Keenan                                                                              Section 3 Page 2
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


alternative explanation to the problem of the wandering planets.

                 Sph
                    ere of fixed stars                 The Copernican view of the solar system
                       Saturn                          is pretty much as we understand it to-day
                       Jupiter                         but only six planets were known about
                     oonMars                           then. Like Aristotle's solar system the
                                                       planets were still held to move on invisible
                    M
                                 Ea
                                                       crystal spheres.
                        Venus      r

                                      th
                                 M
                                 e rcur

                           Sun

                                                       GALILEO GALILEI (1564-1642)
                                      y




                                               In 1604, using the newly invented
                                               telescope, Galileo set out to prove the
                                               theories of Copernicus. The telescope did
                                               not reveal the perfect crystal spheres of
                                               Aristotle. It did however show that the
                                               planet Jupiter had its own moons. This
    The Solar System of Copernicus.           seemed to confirm the solar system of
                                              Copernicus. Galileo used the telescope to
empirically verify Copernicus' theory. Galileo became a champion of the sun centred
universe but met with widespread opposition resulting in his imprisonment. His view of
the universe presented a challenge to many deeply held religious beliefs. He was charged
by the church in Rome of contradicting the Bible by saying that the earth moves.
JOHANNES KEPLER (1571 - 1630)
There were still problems with the behaviour of the planets in the Copernican model.
Using the data of the Danish astronomer, Tycho Brahe,
Kepler came to realise that the planets move, not in circles,
but in elliptical orbits.
ISAAC NEWTON (1642 - 1727)
Every school-pupil has heard the story of how Newton
"invented" gravity by observing an apple fall to the ground.
Of course gravity had been around for quite some time
before Newton! What Newton did do was to realise that the
force which draws the apple to the Earth is the same force
which keeps the planets in their orbit. Kepler had come to 3.
                                                                           Isaac Newton
             3. Scientific Accounts of the Origin of the
                                                                                        Universe
                                                The Development of the Big Bang Theory.
realise that the planets moved in very strict elliptical orbits around the sun. Newton now
combined this observation with the findings of Galileo to produce his theory of


J.Keenan                                                             Section 3 Page 3
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


UNIVERSAL GRAVITATION. Newton's model allowed for predictions to be made. Given
currently available data, it was possible to calculate the future position of the planets,
which could be checked by observation. The solar system was seen as a giant clock in
which everything was predetermined. Newton also started the process of searching for
an underlying principle which would unify a number of different phenomena. This is a
questwhich has been taken up by most of the giants of science and carries on today.
FARADAY for example, discovered that magnetism and electricity were really different
aspects of the same reality. As you will see below EINSTEIN more recently did the
same for space and time.


ALBERT EINSTEIN (1879-1955) AND RELATIVITY THEORY.
                                 At the beginning of this century physics was in a crisis.
                                 Somehow the laws of electromagnetism and Newton's laws
                                 of   motion didn't fit       together. The      laws   of
                                 electromagnetism had been established by MAXWELL.
                                 Since Newton was held in such high esteem it was generally
                                 assumed that Maxwell's equations must somehow be wrong.
                                 Einstein showed that it was Newton's equations that
                                 needed modifying since space and time were somehow
                                 locked together.
                             Think about this: You are on a train travelling at 100
                             kilometres per hour. You decide to get up and go to the
                             restaurant which is at the front of the train. You walk
   Albert Einstein          along the carriage at a speed of 3 kilometres per hour.
Outside the train, at the side of the track, someone watches you through the window.
From their perspective you are travelling at a speed of 103 kilometres per hour but
from your own perspective you are only travelling at 3 kilometres per hour. We can see
that speed is relative to the motion of the observer. Einstein applied the same thinking
to time and space and came up with some strange conclusions which once again
contradict common sense:-All the experiments which have ever been made on the speed
of light have confirmed that light travels at 300,000 kilometres per second in a
vacuum. Einstein wondered about this and asked himself the question, "Would the speed
of a beam of light change if its source were moving in a similar manner?" He found that
it did not and that the speed of light was an absolute constant. Since speed = distance
divided by time, the consequences of this seemed absurd. It meant that if the speed of
                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.
light was fixed, then time itself can't be a fixed constant, as common sense had
previously assumed - that it must be capable of being stretched or shrunk It meant


J.Keenan                                                             Section 3 Page 4
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


that space and time were somehow interconnected and that time was not an absolute
but relative.
Paul Davies says,
   “Einstein demonstrated that time is in fact, elastic and can be stretched and
   shrunk by motion. Each observer carries around his own personal scale of time,
   and it does not generally agree with anybody else’s. In our own frame, time
   never appears distorted, but relative to another observer who is moving
   differently, our time can be wrenched out of step with their time. This weird
   dislocation of time scales opens the way to a type of time travel. In a sense, we
   are all travellers in time, heading towards the future, but the elasticity of time
   enables some people to get there faster than others. Rapid motion enables you
   to put the brake on your own time scale, and let the world rush by as it were. By
   this strategy it is possible to reach a distant moment more quickly than by
   sitting still. In principle one could reach the year 2000 in a few hours. However
   to achieve an appreciable time warp, speeds of many thousands of miles per
   second are necessary. At currently available rocket speeds only precision atomic
   clocks can reveal the minute dilations. The key to these effects is the speed of
   light. As it is approached, so the time warp escalates. The theory forbids
   anyone to break the light barrier, which would have the effect of turning time
   inside out. ---time distortions of this sort are a favourite sci-fi gimmick, but
   there is nothing fictional about them. They really do occur. One bizarre
   phenomenon is the so called twins effect. One twin blasts off to a nearby star,
   nudging the light barrier. The stay-at-home twin waits for him to return ten
   years later. When the rocket gets back, the Earth-bound twin finds his brother
   had aged only one year to his ten. High speed has enabled him to experience
   only one year of time, during which ten years have elapsed on Earth”
All this is no unsubstantiated theory. Experiments in flying very accurate clocks at high
speeds have all verified Einstein’s theory. Speed slows down time and so does gravity.
It also means there is no simultaneous present! One observer might see two events as
simultaneous. For another they might happen in sequence. The theologian and physicist
Ian Barbour in his Aberdeen Gifford lecture said of this, "Because there is no universal
present and no common present separating past and future, the division between past
and future will vary among observers. Some events which are past for one observer,
may well still be future for other observers."
  Another major implication of Einstein's' discoveries about time is that if the universe
                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.
had a beginning then time must have come into existence with space and matter.
Einstein also showed that energy and matter are related through the formula E = MC 2.


J.Keenan                                                             Section 3 Page 5
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


(Energy = Mass x The Speed of Light x The Speed of Light) He also affirmed that
gravity could be understood as bent space.
What we see happening here is that various aspects of the natural world which were
once seen as separate and unconnected are brought into relationship. We see a dynamic
and interconnected universe. Space and time now become space-time, mass is
repackaged energy and gravity and acceleration are the same thing. One of the major
tasks of physics today is to complete the work of Einstein and others by finding a
theory that finally shows the relationship between all things in a unified Theory of
Everything (TOE).


QUANTUM THEORY -THINGS ARE UNPREDICTABLE.
Another great paradigm shift has been stimulated by Quantum Physics - the word
"quantum" means "parcel". Quantum theory is therefore a description of nature, based
on the tiny packets of energy and matter that make up the universe
Certain processes in physics such as radioactivity are random and unpredictable. It
seems that the behaviour of atoms and subatomic particles is very uncertain. In linear
accelerators particles just seem to pop out of nowhere and disappear again into the
void in what would appear to be a completely spontaneous matter. This seems to go
against the world-view presented by Kepler, Newton and Einstein where it was assumed
that all material objects complied strictly with the rules of mechanics- the same rules
which keep the planets in their orbits, or direct the bullet to its target. The atom was
felt to be like a scaled down model of the solar system and therefore governed by the
same predictable rules. However the evidence indicates that the behaviour of
subatomic particles can't adequately be described by these laws due to their
unpredictable behaviour. Quantum theory gives a much greater place to CHANCE than
the Newtonian paradigm although Einstein would not accept this saying “God does not
play dice with the universe”
HEISENBERG (see Section 1.) put forward his uncertainty principle which showed that
it was wrong to ask about an electron’s position and speed at the same time. You can
measure one or the other but not both. According to BOHR, the problem arises from
assuming that an atom is a “thing”. According to him, the fuzzy and nebulous world of
the atom only sharpens into concrete reality when an observation is made. In the
absence of an observation, the atom is a ghost. It only materialises when you look for


                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.
it. And you can decide what to look for. Look for its location and you get an atom at a
place. Look for its motion and you get an atom with speed. But you can’t measure both


J.Keenan                                                             Section 3 Page 6
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


simultaneously. Consciousness and reality, mind and matter seem to interact somehow.
The separation between subject and object is not clear cut.
Heisenberg said “The common division of the world into subjects and objects, inner
worlds and outer worlds, body and soul is no longer adequate.”
If you find this all too strange, Einstein would have agreed with you when he famously
said, “God does not play dice with the Universe.” but experiments carried out in the
80’s show that Bohr was right and Einstein wrong -uncertainty seems to be built into
the micro-world. The experimental evidence supports particles jumping out of nowhere,
events without causes, reality triggered only when you observe it.


YOUNG'S SPLIT SCREEN EXPERIMENT.
Some other strange implications seem to emerge from quantum physics. You may be
aware that light behaves both as a wave and as particle. Young set out to investigate
this ambiguous behaviour of light in the experiment shown below.




                             A
                                                   B                              C


Light is shone through two slits in screen B onto screen C. This causes bands of bright
light separated by dark bands to appear on C. This is an interference pattern caused by
the light waves either adding up or cancelling each other out. What would now happen if
we turn down the amplitude of the source of light so that the light was emitted a
particle (photon) at a time? You would not expect an interference pattern yet this is
exactly what Young found. Even when the light is released a particle at a time, the same
interference pattern is produced.
The implications of this are bizarre:- The photons seem to "know" what each other are
doing. If one photon goes one way then the next photon knows it has to go another way.


                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.
This leads to the conclusion that the potential photon paths somehow thread through
both slits, the path that is not followed influencing the actual path of the photon. Other


J.Keenan                                                             Section 3 Page 7
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


quantum particles are similarly found to behave more like waves than particles.
EDWIN HUBBLE            (1889-1953)       AND     THE     BIG    BANG
THEORY.
Have you ever noticed, standing at the side of the road, that
when a car passes you at speed, the sound of its engine drops
in pitch? This is known as the Doppler Effect and it happens
because as the car approaches you the sound waves are
bunched up, increasing in frequency but as the car moves
away, the sound waves are stretched out and this is
experienced as a drop in pitch. Because, like sound, light also
travels in waves it too is subject to the Doppler effect. If a
source of light is travelling away from you then it appears
more red because light arriving from the source decreases in      Edwin Hubble
frequency compared to if it were at rest relative to Earth. Now the genius of Hubble was
that he applied this to astronomy and came up with the Big Bang theory. Hubble observed
that all the galaxies (groups of stars) were becoming more red which meant they must
be moving away from us. Hubble came to realise that everything in the universe was
moving away from everything else. Since all the galaxies are moving away from each
other the conclusion would be that at one time all the galaxies were compressed into a
small space, their current motion being explained by a giant cosmic explosion. His
theories were confirmed in the sixties when two scientists working for the Bell
Telephone Company discovered the remains of the radiation emitted by the big bang.
The Big Bang Explanation of the universe is supported by a great deal of evidence and is
almost universally accepted.

This universe of space, matter and time came into existence some 15 - 17.5 billion years
ago in an enormous explosion. Before that there was nothing at all. By nothing we mean
no time, no space and no matter. (Since there was no time before the Big Bang it is
meaningless to ask what was before the Big Bang.)

3.5 minutes after the explosion the basic building blocks of the universe, atomic nuclei
were formed- 1 million years later the first atoms were formed (these were the atoms
of hydrogen and helium when electrons joined with the nuclei.)

Millions of years later these atoms began to form into vast clouds, slowly spinning.
These clouds were the beginning of galaxies. Within these young galaxies, smaller
                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.




J.Keenan                                                             Section 3 Page 8
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


clouds of gas developed. The effect of gravity made them spin faster and also made
them very hot; so hot that nuclear reactions occurred which produced the first stars.

Within stars hydrogen atoms fuse to form helium. Eventually, when a star becomes old,
it becomes unstable and other elements start to be fused. For example, 3 helium atoms
will form a carbon atom, 4 heliums will form an atom of oxygen and so on. Eventually the
star erupts in an explosion, throwing its elements out into space.

About 4.5 billion years ago it is probable that a neighbouring star went supernova. The
debris from the resulting explosion was pulled into the orbit of our sun. This matter
formed the planets of our solar system.

So the universe is not infinitely old but had a beginning. Up until recently many
scientists had held the belief that the universe was infinitely old. The reason why the
scientific community accept that the universe had a beginning stems from a body of
evidence known as the second law of thermodynamics.

Paul Davies says,

 "In its widest sense this law (the second law of thermodynamics) states that every day
the universe becomes more disordered. There is a sort of gradual but inexorable
descent into chaos. Examples of this law are to be found everywhere; buildings fall
down, people grow old, mountains and shorelines are eroded, natural resources are
depleted......

At first sight there seem to be many counter-examples of this law. New buildings are
erected. New structures grow. Isn’t every new - born baby an example of order arising
out of disorder? In these cases you have to be sure you are looking at the total system,
not merely the subject of interest. The concentration of order in one region of the
universe is always paid for by increasing disorder some-where else. Take the
construction of a new building, for example. The materials used inevitably deplete the
world’s resources, while the energy expended in the building process is also lost
irretrievably. When a full balance sheet is drawn up, disorder always wins...... Physicists
have invented a mathematical quantity called entropy to quantify disorder, and many
careful experiments verify that total entropy in a system never decreases......

If the universe has a finite stock of disorder, and is changing irreversibly towards
disorder two inferences follow. The first is that the universe will eventually die,
wallowing, as it were, in its own entropy. This is known among physicists as the heat
                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.


J.Keenan                                                             Section 3 Page 9
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


death of the universe. The second is that the universe cannot have existed for ever,
otherwise it would have reached its equilibrium end state an infinite time ago.
Conclusion: the universe did not always exist."

The universe is not infinitely old nor is it infinite in size. According to Einstein it can be
imagined as the surface of a sphere bending back on itself, without edges.

A further major argument against an infinite universe is based on logic for in an infinite
universe anything would go. All possibilities would become inevitabilities as the
combination of conditions which produced the present situation were endlessly repeated
with an infinite number of variations. This would lead to some impossible consequences.
Think about it - as well as the normal you here, there would inevitably have to be an
infinite number of exact copies and very near copies of you. Somewhere you would be
the prime-minister, somewhere else you would be suffering in great pain, somewhere
else you would be Cliff Richard as the conditions that made you were repeated over and
over again in an infinite multitude of variations.




J.Keenan                                                           Section 3 Page 10
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


                             3. Scientific Accounts of the Origin of the Universe
                                                The Development of the Big Bang Theory.


THE THEORY OF EVOLUTION.

                               Within the scientific community, the theory of evolution has
                               become widely accepted as the best explanation for the
                               origin and development of human life. The theory is
                               particularly associated with Charles Darwin (1809 - 1882)
                               although evolutionary theories can be traced back to ancient
                               Greece. Until the end of the 18th century it was commonly
                               thought that the world was about 6000 years old, that each
                               species had been created separately; and that no one
                               species could develop out of another. Such beliefs, based on
                               a literal interpretation of the biblical accounts of creation,
                               were challenged by developments in geology and biology.

                            William Smith (1769-1839),
a drainage engineer and amateur geologist, collected
information about rock strata and the fossils contained in
them. He saw that the deeper strata were older than
those near the surface. Because the fossils in each
stratum showed life forms very different from those of
today, he concluded that there had been many successive
acts of creation. He took the six days of creation in
Genesis to refer to six geological periods.

In Principles of Geology (1830) Charles Lyell argued that
geological changes were going on all the time, and that
there did not have to be a number of separate acts of
creation to explain the different strata and fossils in the rocks. His theory,
Uniformitarianism was opposed to the catastrophic theories which argued for a series
of acts of creation, each followed by a catastrophe, the latest of which had been the
flood of Noah's time.Lyell argued that God created a succession of life forms, by
natural means, discoverable by science. Apart from the fact that creation was thought
of as a continuing process, there was not a great difference between this theory and
William Paley's belief that God had designed the world. The older strata held
creatures that were extinct, and the younger ones had animals like those of today, but
there were no human fossils. It was therefore concluded that mankind was a very
recently created species.



J.Keenan                                                           Section 3 Page 11
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)




                                          3. Scientific Accounts of the Origin of Life
                                                                      The Theory of Evolution.

                            In the 18th century a Frenchman called Lamarck developed
                            a theory of evolution. He started from the observation that
                            we inherit characteristics from our parents. For instance,
                            if your parents have brown eyes, then the chances are you
                            will also have brown eyes. Lamarck suggested that an animal
                            might acquire characteristics during its lifetime which it
                            passes on to its offspring. A horse for example might
                            stretch its neck by continually reaching for the leaves at
                            the top of trees. When it mates, perhaps its young are born
                            with slightly longer necks. The offspring continue to
                            stretch     for    the
                            higher leaves and in
turn stretch their necks even further. Their even
longer necks are then passed on to the next
generation who in turn pass yet even longer necks
on to the next generation and so on. After some
generations we have a giraffe! This is a different
species of animal. Lamarck suggested that other
animals have adapted to their environment in a
similar way. The drawback with this solution is
that there is no evidence that we hand on
characteristics which have been gained in our own
lifetime. The data doesn't support the hypothesis. The evidence supported gradual
change over time but the mechanism whereby this was achieved was still a mystery.

     It was Darwin who gave a plausible explanation of how evolution might occur. Charles
  Darwin was born of a wealthy parents. Originally he had studied medicine at Edinburgh
 University but gave it up to study religion at Cambridge. While he was there he became
         interested in the writings of William Paley and biology. Paley argued that the way
        animals are so well adapted to their environment was evidence that they had been
   designed by God. Initially Darwin was much impressed by this argument but as a result
           of a 5-year voyage around the world, Darwin began to see an alternative way of
explaining how living things suited their environment. When Darwin was in the Galapagos
Islands, he observed 13 different kinds of finch, and noted that each of the islands had
 its own species of giant tortoise. Darwin started to question Paley's ideas. He could see
    no point in God creating different species for each island. Until then, in keeping with
   the teaching of the Bible, it was believed that God had created each species of animal


J.Keenan                                                           Section 3 Page 12
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


                                          3. Scientific Accounts of the Origin of Life
                                                                      The Theory of Evolution.

separately. This idea was known as the fixity of species. Darwin's observations in the
Galapagos islands caused him to question this idea. It seemed more likely, as Lyall had
argued in the case of geology and Lamarck in the case of biology, that change occurred
gradually over a great period of time and that as argued in the case of geology the
various species had not been specially created but that they had somehow developed
from existing species. Darwin saw in the ideas of Thomas
Malthus the means by which this occurred. In 1789
Malthus had published An Essay on the Principle of
Population. Malthus argued that contrary to Paley's cosy
view of nature, all living things were engaged in a fight for
survival in which only the fittest survived. (This was
brought about because more individuals than can survive
are born. Those animals and plants which are not well
adapted to their environment die out.) Darwin now took
this idea and applied it to the problem of evolution. Darwin
believed that evolution occurs through natural selection.
Artificial selection occurs when stock breeders allow
certain animals to mate in order to develop specific
qualities - A horse breeder, for example, only allows race
winners to breed and in this way develops faster running horses. Darwin observed that
in each generation of a species there are always some variation. Some are taller than
others, others have longer legs or bigger beaks, or thicker fur for example. These
variations either give a particular individual an advantage or a disadvantage in the
struggle for survival. Let's say a group of rabbits come under threat from an increased
fox population. The rabbits with the longest legs will be able to run fastest and escape
the foxes. Because they have a better chance of surviving into maturity, they have a
better chance of reproducing and passing their long legged characteristic onto the next
generation. In time the long legged rabbits would come to predominate over their
shorter legged cousins. In this way useful characteristics would be passed onto the
next generation. After hundreds of generations one species could develop into another.
Darwin had turned Paley's teleological ideas back to front. (teleology – idea that things,
events are geared to a purpose.) The giraffes did not have long necks in order to eat
the leaves at the top of the trees. Rather giraffes could eat the leaves at the top
of the trees because they had long necks.

In the 1950's two scientists, Crick and Watson worked out the structure of DNA. As a
result the mechanism whereby characteristics are passed on from one generation to the
next came to be fully realised.


J.Keenan                                                           Section 3 Page 13
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


                                          3. Scientific Accounts of the Origin of Life
                                                                      The Theory of Evolution.

                            You are made of and controlled by proteins. Proteins in turn are
                            made of amino acids. Different combinations of amino acids give
                            different proteins. The proteins which make you up have been
                            manufactured in your cells under the controlling influence of
                            stuctures known as chromosomes which in turn consist of genes
                            made of DNA. Basically the DNA tells the amino acids how to
                            form up to make the various
                            proteins. The DNA can be
                            likened    to    a    computer
   Crick and
                            programme consisting of a set
   Watson
                            of instructions which is run on
                            the hardware of the cell.

Half the complement of genes you have in your cells
comes from your mother and half from your father.
You therefore resemble your parents because your
genes are instructing your cells to manufacture
proteins similar to those of your parents. However, you
differ from your parents because each new combination
of genes is unique. This is what accounts for the variety
within a species necessary for evolution to occur.

Occasionally something can go wrong when the sex cells which transmit the genes from
one generation to the next are being formed. This is known as gene mutation. Usually
gene mutation leads to offspring which are handicapped in some way and less well
adapted to their environment. However, occasionally the process of gene mutation can
lead to advantaged offspring, better adapted to their environment than their parents.
In the fight for survival such offspring have a better chance of reaching maturity and
reproducing. The advantage brought about by gene mutation is thus passed on to
succeeding generations. Gene mutation accounts for the more dramatic changes within a
species and is a further factor involved in the evolutionary process.

How Did Human Life Develop?

The theory of evolution now gives us an explanation of how human life developed in
marked contrast to that based on a literal interpretation of the Bible. Life can be said
to have started with the first molecule of DNA. How this came about is not yet
understood but many biologists say by the chance collision of atoms. Others find



J.Keenan                                                           Section 3 Page 14
Religious, Moral and Philosophical Studies. Christianity: Belief and Science (Higher)


                                          3. Scientific Accounts of the Origin of Life
                                                                      The Theory of Evolution.

problems with this as we shall later see. The development of DNA eventually led to the
first single cell animals, rather like the amoeba found in pond water today. Through a
process of gene mutation, more complex, multiple cell organisms developed. In time
these evolved into fish. From the fish, reptiles developed and in time fully fledged land
animals. From these the mammals developed leading to the arrival of the primates
(monkey family) and finally us homo sapiens sapiens.

FURTHER : Download and watch the video clips – Big Bang and Darwin and the Theory of
evolution.




J.Keenan                                                           Section 3 Page 15

				
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