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EVOLUTION
WHERE, WHEN & HOW DID HUMAN RACE ARISE?
EVOLUTION
The universe, the stars, the earth and
all living things have evolved through
a long history that was not fore
ordained or programmed. History of
continual and gradual change shaped
every thing by processes consistent
with the laws of physics ORIGINS OF HUMANKIND Discovery of unusual human bones in 1856 in The Neanderthal Valley, Germany.
Pronounced bony ridges over the eyes
Backward sloping forehead
Receding chin
Unusually prominent teeth
Brain larger than our
HUMAN KIND
Humans
are creatures whose roots lie
in the animal. They are described as
animals who make tools, reason, use
fire, laugh or many other things.
Humans are animals who wonder,
intensely and endlessly about their
origin.
EVIDENCE FOR EVOLUTION
THE MISSING LINKS
•  Fossils are the remnants of ancient
plant and animals that has become
extinct.
•  Similar strata contained similar
fossils
•  Lowest strata contained the oldest
•  Life forms change slowly in the
direction of modern life
•  Discovery of JAVA man by Marie Eugene
Dubois in 1891
•  Discovery of PEKING man in 1923
•  Raymond Arthur Dart found fossils of
Australopithecus Africanus TAUNG child in
1924 which was 2.5 million years old
•  Donald Johnson discovered 3.2 million years
old Australopithecus, LUCY in 1974
•  Gen Suwa discovered 4.4 million years old A.
Aramis in 1994 in Ethiopia.
EVOLUTION IS
•  Recklessly opportunistic. It
favors any variation that can
provide a complete advantage
over the other member of and
organism.
•  There is no programmed control
or direction for the progression. THE ORIGINS OF
SPECIES
1859 CHARLES DARWIN
DARWIN’S PRINCIPLES OF
EVOLUTION
EVOLUTION VIA NATURAL
SELECTION
•  The world is not static but evolving
•  The process of evolution is gradual and
continuous
•  Similar organisms are related and decent from a
common ancestor
•  There is a process of Natural Selection which is
a two step process.
– Variations in generations
– Survival of the fittest
•  Production of genetic variability: A
random intrinsic process which proceeds
via mutation, recombination and chance
events.
•  Ordering of that variability be selection:
An extrinsic ordering which determines
the evolutionary direction.
ARGUMENTS AGAINST
EVOLUTION
•  If the diversity of species is due to
evolution, it should be still going but
one cannot see it.
•  God is perfectly capable of creating life
•  There should be a guiding intelligence
behind evolution
•  It is not deterministic
COUNTER ARGUMENTS FOR
BIOLOGICAL EVOLUTION
•  Evolution goes so slowly that it is
not visible to naked eye.
•  If one argues that it is God s will,
than science comes to an end.
•  Need for a guiding intelligence?
QUESTIONS DARWIN COULD
NOT ANSWER
BIOLOGICAL BASIS FOR
EVOLUTION
•  How do offspring's inherit from
parent?
•  Why do living things vary and
how variation occurs?
•  What rules govern the handing
down of traits from one generation
to the next?
•  Heredity is transmitted by a large number of
independent, independent units known as genes.
•  When parents contribute the same kind of gene,
a constant characteristic is produced in the
children. A hybrid results from two different
kinds.
•  Evolution is the changes in the genetic
composition of a population with the passage of
each generation. CHROMOSOME
Mendel s
Experiment
on Peas
Chromosomes are microscopic
bodies found in the nuclei of plants
and animals that carry the
hereditary materials. They are
called genes that determine the
growth, development and
characteristics of an organism.
DEOXYRIBONUCLEIC
ACID (DNA)
DNA is the genetic substance of all living
cells in which the hereditary information
is transmitted from each generation to the
next by the codes present. These
molecules are very long, one dimensional
chains, composed of four types of
subunits. The genetic information is
conveyed in the sequence of the subunits.
MUTATION
A mutation is the alteration of the
genetic code which than results in
the wrong amino acid sequences
after translations. Mutations may
not always be harmful for the
organisms. Mutations can be either
hereditary or they are acquired. GENE POOL •  A gene is the functional unit of DNA. The
code written in the genes is translated into
aminoacid sequences that constitutes the
proteins. All the genes possessed by a
population constitutes its gene pool. If there is
a random mating within a large population and
if there are no mutations, the gene pool within
the population will remain constant. Genetic
equilibrium will be maintained and no
evolution will occur.
TYPES OF MUTATIONS • Hereditary mutations.
• Acquired mutations
• Chromosomal mutations
• Mutagens
HEREDITARY MUTATIONS •  Genes come in pairs (one from each parent).
Many genes have in several variant forms
known as alleles. Different alleles produce
variations in inherited characteristics. The
observed trait may be dominant or recessive. If
both alleles in a particular gene is same, the
individual is said to be homozygous, if
different, heterozygous for that trait. In
heterozygous case, a dominant allele prevails
over a normal allele.
ACQUIRED MUTATIONS •  They arise within individual cells and
accumulate throughout a lifetime. They are
generally due to errors that occur during DNA
replications and cell divisions. They may also
arise by exposure to environmental mutagens
such as radiation and toxins. Cells have repair
mechanisms, however, they may become less
efficient with age or mistakes may accumulate
over time. These are passes only to the direct
descendants of those cells.
CHROMOSOMAL MUTATIONS •  These can occur at chromosomal levels during
cell division. Especially important for woman
having babies at old age. When large regions of
chromosome are altered, it may loose the ability
to separate during normal cell divisions. This way
the new cell may get more or less of its share of
DNA. When there are extra or too few copies of
the gene, the cell runs into trouble. Down
Syndrome is chromosomal abnormality which
involves an extra copy of chromosome 21.
MUTAGENS Agents that cause mutations such as:
• 
• 
• 
• 
• 
UV radiation
Temperature
Toxins (mustard gas, benzopyrenes, aflotoxins)
Acrylic dyes
Alkylating agents FACTORS ALTERING GENETIC
EQUILIBRIUM
Y-CHROMOSOME VARIATION IN THE
TURKISH POPULATION •  Mutation: Inheritable change in the structure of a
gene which occurs randomly at a low but constant
rate.
•  Natural Selection: Species that can cope with the
environment including climate, competitors and
predators will have chance to evolve.
•  Genetic Drift: Isolated human population may
undergo genetic changes as a result of chance rather
than natural selection.
•  Mixing: Mixing of geographically defined
populations
Y-CHROMASOME HAPLOTYPES OF
TURKISH POPULATION
REGIONAL
VARIATION OF
YCHROMOSOME
OF TURKISH
POPULATION
PRINCIPAL COMPONENT ANALYSIS OF YCHROMOSOME VARIATIONS OF WORLD
POPULATIONS
YCHROMOSOME
COMPARISON
OF WORLD
POPULATIONS
STATISTICAL COMPARISON OF YCHROMOSOMES