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Impact of Evolution on Human Thought. Evolution


Farid Gazizov
Impact of Evolution on Human Thought
Evolution


      Evolution by definition of Webster dictionary is a gradual development
of simple  matters  into  more  complex.   When  most  of  the  people  hear
“evolution”  it  associates  with  development  or  history  of  the  earth.
History of the earth compiles of gazillions of steps.  The very  first  step
in our history is a birth of the earth, which  took  place  over  4  billion
years ago.

      “Powerful telescopes reveal new stars coalescing from  galactic  dust,
       just as our sun did more than 4.5  billion  years  ago.   The  earth
       itself formed shortly thereafter, when rock, dust, and gas  circling
       the sun condensed into the planets of our solar system.  Fossils  of
       primitive microorganisms show that life  had  emerged  on  earth  by
       about 3.8 billion  years  ago  (Teaching  about  evolution  and  the
       Natural of Science, ch. 1).”

      Many  people  throughout  the  centuries  have  been  trying  to  find
explanations to the questions like: Why are surrounding us  things  the  way
they are?; why some type of animals resemble another one?  It  was  hard  to
answer these questions  without  proper  tools,  experience  and  background
knowledge.  Even nowadays, not all questions are answered.  Darwin  was  the
first human who succeeded in responding to  these  questions.   He  was  the
first one who put discovered facts and knowledge available by  his  time  in
one big picture.  In attempts to explain  the  history  Darwin  created  the
most outstanding achievement of human beings that  had  enormous  impact  of
our thinking—evolutionary thinking.  Ernest Mayer, in  his  book  “One  Long
Argument” says following about impact of Darwin’s work on human thinking.

       “It is almost impossible for a modern person to project back to  the
       early half of the nineteenth century and reconstruct the thinking of
       this pre-Darwinian period, so great has been the impact of Darwinism
       on our views (E. Mayr, pp. 1)

      For our further discussion, one should explicitly distinguish  between
evolution and evolutionary theory.  Evolution  (history)  is  a  serious  of
facts that occurred since the birth of the earth, while evolutionary  theory
is the best way available nowadays to explain  why  evolution  happened  the
way it happened, but not otherwise. Both evolution and  evolutionary  theory
make series of claims.  Some of them are secondary  and  some  are  primary.
Primary claims if proved wrong, would change entire theory.



                         Primary Claims of Evolution


      The earth is over 4 billion years old. In the past when technology was
not very developed it was hard to prove age of the  earth.   Scientists  had
been aging by measuring  the  rate  of  sedimentation.   Another  method  of
defining age, which was used in 1800s, is  noticing  what  kinds  of  fossil
rocks have.  Currently it is done by chemical  analysis  of  composition  of
fossil.

       “Some elements such as uranium, undergo radioactive decay to produce
       to  produce  other  elements.   By  measuring  the   quantities   of
       radioactive elements and elements into which they  decay  in  rocks,
       geologists can determine how much time has elapsed  since  the  rock
       cooled from initially molten state (Teaching About Evolution and the
       Nature of Science).”

      Life on the earth did not appear right after appearance of the  earth.
 The first sings of life were dated about 550 million  years  ago  according
to the oldest fossils.  This fact does not specifically mean that where  was
not life forms before that time.  Life forms were  very  simple  and  lacked
hard parts like bones or shells and could rarely preserve in the fossils.

      “However, a few pre-Cambrian organisms left traces of their existence.
        Some ancient rocks contain stromatolities—the remnants  of  bacteria
      that grew in columns like stacked pancakes (Teaching About  Evolution,
      ch. 3, pp. 2)

      Extinction is a major feature of biological evolution.   It  is  in  a
tight connection with natural selection.  Natural selection  works  only  by
means of  surviving  of  changes,  in  some  sense  useful,  and  therefore,
striking root.  In the consequence, fast increase  of  the  numbers  of  all
organic matters in geometrical progression, every  natural  habitat  already
filed to the limits by its habitants.   From  this  it  follows  those  more
adapted forms will increase in numbers and less adapted,  will  decrease  in
numbers and become rare.  Rarity  of  the  form  is  a  predecessor  of  the
extinction.  Every form represented by small numbers of individuals has  big
chances for a complete extinction in  consequence  of  significant  climatic
swings within a year or in consequence of  temporary  increase  of  enemies.
Species,  most  abundant  of  individuals,  have  the  biggest  chances  for
appearance at any particular time of favorable  changes.   Rare  individuals
will at any particular time change and perfect  at  a  slower  pace  and  in
consequence of that will be defeated in a life  struggle  with  changed  and
improved descendants of more common individuals.  From this it follows  that
since with a passage of time natural selection “creates” new  species,  than
other species become more rare, and finally extinct.

      For example, during laying eggs season, sea turtles  hay  hundreds  of
thousands eggs.   While hatching and  getting  to  the  ocean  most  of  the
generation becomes easy pray of sea birds.  Since just  hatched  turtles  do
not have a hard cover that could protect them,  many  of  them  dye  in  the
ocean.  By maturity time only about one out of thousand turtles stay  alive.
 Currently there are billions of living organisms that  inhabit  the  earth,
but they represent only around one percent  of  all  living  organisms  that
have ever lived on the earth since its  birth.   Ninety  nine  percent  dyed
out.[1]


            Another example  that  mechanisms  of  evolutionary  change  are
observable and verifiable is the one described by Henry Walter Bates.

             “In  1862,  Henry  Walter  Bates  made  brilliant  use  of  the
      Darwinian mechanism of natural selection asking why it  is  that  some
      species  of  butterfly  very  closely  mimic  species  of   butterfly,
      essentially quite different, Bates proved beyond doubt that the answer
      lies in adaptive advantage brought about by  natural  selection.   The
      mimicked insects are highly distasteful to birds who think  that  they
      belong to distasteful species.  Bates showed experimentally that birds
      learn to avoid distasteful insects, and that the closer the mimic, the
      less change there is that the insect will be eaten.”



                        Secondary Claims of Evolution


      When the earth appeared for the first time it was very different  from
its current conditions.  The surface of the earth was  represented  by  bare
bedrock.  At the time of its  birth,  the  earth  represented  cold  matter,
close by its composition to meteorites.  Material it was mad  of,  contained
radioactive  elements.   In  consequence  of  the   heat   excretion   while
radioactive  decomposition  of  the  core  and  gravitational   compression.
However, because of continuous loss of heat through he surface and  lack  of
radiation heat complete melting of the earth did not happen.  In  result  of
earth’s melting, water and different gases were brought up to  the  surface.
This water began formation of hydrosphere.

      Location of continents and oceans were very different.   According  to
Wegener’s  hypothesize,  which  he  later  supported  by  evidence,  earth’s
continents used to be a single land, which was called  Pangea.    About  two
hundred million years ago  Africa  and  South  America  slowly  began  their
movement toward their current location.  Wegener supported  his  hypothesize
by geological and biological evidence.  At the place  where  the  continents
were aligned, were found fossilized animals and plants dated more  than  two
hundred million years old.  Besides, if Africa and South America had  always
been separate continents as they are now, both of them would have  had  very
different flora and fauna, which are not.

      Starting at 1950 up to 1970 evidence begin exposing to the world  that
support hypothesis of continent’s  slow  movement.   Sonar  mapping  of  the
ocean floor showed winding, continuous  ridges  system  around  the  planet.
The ridges appeared where molten matter  was  coming  up  from  the  earth’s
inside.

      Not  only  topography  of  the  earth  has  changed,  but  composition
atmosphere has changed as well.    Current  atmosphere  contains  a  lot  of
oxygen, which is result of existence of life.  During photosynthesis,  green
plants consume water and dioxide and release oxygen in atmosphere.  This  is
considered to be a secondary claim because  even  if  the  earth  would  not
developed as it considered, it would have no impact on evolutionary  theory.



      Origin of human being was an interest of human  more  than  origin  of
plant and animals.  Attempt to understand and explain origin  of  humans  is
expressed in religions, legends of all kind of  trails  and  folks.   For  a
long period of time science knowledge were abrupt and  incomplete  in  order
to solve  a  problem  of  human  origin.   Only  in  1857  Darwin  expressed
hypothesis, and in 1871 in his book “The  Origin  of  man  and  relation  to
sex,” convincelly proved that humans originate from pre-existing  humanlike,
but were not created by  intelligent  designer.   Role  of  social  factors,
which was pointed out by Darwin, was detailly described  by  Fredrik  Engels
in his book “Role of labor in the  process  of  turning  ape  into  humans.”
(1896)

      Human and vertebrates commonness  is  strongly  supported  by  similar
arrangement of  internal  organs:  skeleton,  nerve  system,  blood  system,
respiration, and digestion.

      Rudiments  and  atavisms  are  very  important  evidences   of   human
relatedness to animals.  There are about 90 rudiments in human body:  coccyx
bone (remaining of the reduced tail);  folds  in  the  corner  of  the  eyes
(remaining of the blinking  tympanum;  thin  body  hair  (remaining  of  the
hair).  All these rudiments are  inherited  from  an  animal  ancestor.   An
external  tail,  which  sometimes  people  are  born  with,  is  related  to
atavisms.  Another atavism is abandon hair on the face and body.

      Common  details  of  the  body  arrangement  are  evidence  of   close
relativeness of human and anthropoids: wrist with flat nails, shape of  eyes
and years, the same number of canine and molar  teeth,  complete  change  of
baby teeth, and so forth.  Physiological commonness is very important:   the
same blood groups, diseases (tuberculosis,  fly,  smallpox,  cholera,  AIDS,
pneumonia) and parasites (louse).  Besides numerous common  features,  there
is a number of explicit  differences  evidencing  that  its  current  stage,
human is considered to be different species.   Only  human  has  ability  of
upright walking and related to that  peculiarity  of  structure  of  the  S-
shaped backbone with explicit neck and lumber  bend,  low  extended  pelvis,
and etc.  Human skull is higher and more rounded without superciliary  arch;
brain part of skull is in most part  dominated  by  facial;  high  forehead,
weak jaws with small canine.  Human  brain  is  about  two  and  half  times
bigger than one of humanlike apes, and 3-4 times heavier.

       Human being evolved from other pre-existing species.  Even in ancient
times it has been noticed that humans have a lot of in common with  a  other
animals just like other animals human had the same internal  organs  (heart,
lungs, liver etc.).  Ancient Greeks had a scale of  living  organisms  known
by their time.  Human being was placed at the end of the scale.  Below  were
higher animals like houses, sheep and so forth, but it is  hard  to  believe
that humans were next step in the biological evolution of  living  organisms
right after higher animals.  Only by the eighteenth century  ape-like  being
became known to Europe. This discover shed  light  on  a  huge  gap  between
higher animal and humans (Darwinism defended, Ruse, pp.  230).   After  that
some scientists (for example Huxley)  assumed  that  humans  descended  from
apes.  Later, having examined  all  differences  between  apes  and  humans,
Huxley came to conclusion that humans  and  apes  descended  from  a  common
ancestor.  One would probably ask why our common  ancestor  did  split  into
two branches, apes and Australopithecus afarensis (which  is  considered  to
be an ancestor of all hominids).  There is a scientific  explanation,  which
relates to climatic changes in Africa.  Our ancestor was  used  to  live  in
the area of heavy precipitation. With a  passage  of  time  climate  started
turning into dry  one  and  forestlands  began  retreating,  leaving  behind
Savannah’s.   Some  species  stayed  in  dwindling  forests.   Others   (our
ancestors) started advancing toward opened spaces.

      With a change of place of inhabitation, there  were  some  changes  in
diet of our ancestor.  Anthropologists suggested that tooth  reduction  took
place because our ancestor started to use grass seeds  and  the  like  as  a
food source (Darwinism Defended).



                     Major Claims of Evolutionary Theory


      Natural selection is the major moving factor of the evolution  of  the
living organisms.  Almost at the  same  time,  several  English  naturalists
arrived at the idea of existence of natural selection (P. Mathew (1831),  A.
Blight (1935), A.  Wallace  (1858),  C.  Darwin  (1858)),  but  only  Darwin
succeeded in exposing of the meaning of this phenomenon as the major  factor
of evolution and created the theory of natural selection.  On the  contrary,
to artificial selection held by humans, natural selection is conditioned  by
influence of surrounding  environment  upon  the  organisms.   According  to
Darwin natural selection is survival of the most accommodated organisms,  in
consequence of which, on the basis of undefined inherited changeableness  in
the series of generations evolution occurs.

      In  process  of  natural  selection  species  more   accommodated   to
surrounding  environment  survive,  those  who  do  are  not,  go   extinct.
Explicit example of that is our ancestors that  had  advantage  of  standing
upright to  look  out  and  look  for  possible  object  of  prey.   Natural
selection does not specifically have to lead to perfection.  It  leads  only
to surviving of species that can survive.   If  entire  kind  of  particular
animals can not survive in changed environment, entire kind will dye out.

      “Organisms in nature topically produce more offspring that can survive
      and  reproduce  given  the  constraints  of  food,  space,  and  other
      resources in the environment.  These offspring often differ  from  one
      another in ways that are heritable—that  is,  they  can  pass  on  the
      differences  genetically  to  their  own  offspring.    If   competing
      offspring have traits that are advantageous in  a  given  environment,
      they will survive and pass on those traits.  As  differences  continue
      to accumulate over generations, populations of organisms diverge  from
      their ancestors.”

      Process of natural selection consists of two steps:  the first one  is
reproduction of genetically different species; the second step is  surviving
of the most adopted individuals in surrounding environment. An  example  can
be nest of birds in  which  some  nestlings  have  a  little  bit  different
coloring than others.  If this coloring better matches the tree these  birds
in habit, this will give them advantage of  better  hiding  from  predators,
which leads to increase in changes of reproduction.  Below are example  that
Wallace, Alfred Russle uses in his book  “Contributions  to  the  theory  of
Natural Selection” to demonstrate natural selection.

      “The Duke of Argyll, in his  “Reigh  of  Law,”  has  pointed  out  the
      admirable adaptation of the colors of the woodcock to its  protection.
      The various browns and yellows and pale ash-color that occur in fallen
      leaves are all reproduced in its plumage, so that  when  according  to
      its habit  it  rests  upon  the  ground  under  trees,  it  is  almost
      impossible to detect it.  In snipes the colors are modified so  as  to
      be equally in harmony with the prevalent forms and  colors  of  marshy
      vegetation.  Mr. J.M.Lester, in a paper read before the  Rugby  School
      Natural History Society,  observes:  --“The  wood-dove,  when  perched
      amongst the branches of its favorite  fir,  is  scarcely  discernible;
      whereas, were it among some lighter foliage, the blue and purple tints
      in its plumage would far sooner betray it.  The robin  redbreast  too,
      although it might be thought that on its breast made it much easier to
      be seen, is in reality not at all endangered by it, since it generally
      contributes to get among some russet or yellow  fading  leaves,  where
      the red matches very well with the autumn tints, and the brown of  the
      rest of the body with the bare branches.”

      Core of natural selection is variation within the kind.  If  variation
does not exist either entire kind will survive  and  stay  unchanged  or  it
will go extinct.  But what it a source of variation? The ultimate source  of
variation is mutations in genes.  If  new  traits  gained  through  mutation
leads to successful survival  and  reproduction  than  new  traits  will  be
inherited and  spread  within  the  population.   Mutation  is  random,  but
natural selection is not.

      All living organisms that currently inhabit  the  earth  share  common
ancestry.  Through the history by means of natural selection  and  variation
first, simple forms of life  were  evolving  into  different,  more  complex
forms.   How to prove it?

      “The discovery of the structure of DNA  by  Francis  Crick  and  James
      Watson in 1953 extended the study of  evolution  to  most  fundamental
      level the sequence of the chemical basis in  DNA  both  specifies  the
      order of amino acids in proteins and  determines  which  proteins  are
      source of both change and continuity in evolution.   The  modification
      of DNA through  occasional  changes  or  rearrangements  in  the  base
      sequences underlies the emergence of  new  traits,  and  thus  of  new
      species, in evolution.  At the same time, all organisms use  the  same
      molecular codes to translate DNA base  sequences  into  Protein  amino
      acid sequences.  This uniformity in genetic code is power evidence for
      the interrelatedness of living things.” (Teaching About Evolution  and
      the Nature of Science, ch. 2, pp. 4)

      Another powerful argument that supports  common  ancestry  is  a  fact
that man is developed  from  an  ovule,  about  the  125th  of  an  inch  in
diameter, which does not differ from the ovules  of  other  animals.   At  a
very early period, the embryo  can  hardly  be  distinguished  from  another
member of vertebrate kind.


      In order to convince one that evolution happened the way  evolutionary
theory describes  it  evidences  must  be  presented.   Major  evidence  and
argument  of  evolutionary  theory  is  that  all  of  the   mechanisms   of
evolutionary theory change  are  currently  observable.   Let  us  take  for
example main mechanism of evolutionary change—natural  selection.   Nowadays
our  society  is  facing  serious  public  health  problem.   Bacteria  that
medicine used to  successfully  fight  with  antibiotics  is  becoming  more
resistant to one.  This means that week bacteria go extinct and only  strong
(more  resistant  to  antibiotics)  bacteria   survived.   (Teaching   about
evolution, ch. 2, pp. 5)  “continued use and overuse of antibiotics has  had
the effect of selecting for resistant  population  because  the  antibiotics
give these strains and advantage over non-resistant strains”



                                Bibliography


   1) “Long Argument,” Ernest Mayr, Harvard University Press, 1991.

   2) “Darwinism defended,” Michael Ruse, Addison-Wesley Publishing Company,
      1982.

   3) “The Descent of Man and Selection in Relation to Sex,” Charles Darwin,
      1974.

   4) “Wonderful Life,” Stephen Jay Gould, W.W. Norton  & Company, 1989.

   5) “Contributions to the theory of natural  selection,”  Wallace,  Alfred
      Russel, AMS Press, 1973.
-----------------------
[1] Teaching about Evolution

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A. afarensis

A. africanus

H. habilis

A. robustus

H. erectus

H. sapiens




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