Session 3 – Natural Selection & Mutations
In this session we will examine to big topics
in the theory of evolution
We will briefly look in more detail how the
mechanism of natural selection works
And we will then look at many common
examples of beneficial mutations, and see if
they show evidence that evolution could
explain life on earth as we know it
Natural Selection
As we said on week one, Darwin did not
think of the idea of evolution, he provided a
mechanism to explain how it could happen
(Natural Selection)
The idea of natural selection is not a hard
one to understand, survival of the fittest is
another term to describe what is going on
during natural selection
How does it work?
Here is another
way to look at
natural selection
in dogs
Long hair is
beneficial in a
cold
environment,
short hair is
beneficial in a
hot environment
We will see real examples of this as we go
through this session, where different traits
exist that have caused the population to
survive (and the old trait to die out)
Natural Selection needs something that
makes one organism more or less fit than
another organism
This is where mutations come into play,
which are vitally important for evolution
Mutations
When we talk about mutations, we are
talking about them changing the DNA
There are several ways that these mutations
can come about (no need for details here)
We will instead look if mutations are able to
bring about evolution as is claimed by
evolutionists, and we will look at many
examples that are given of mutations
Mutations can be classified into three groups
(based on how they affect the organism)
Beneficial, neutral, or deleterious
“Mutations can be classified as deleterious,
neutral or beneficial with beneficial being
by far the smallest category. Beneficial
mutations typically lead to relatively small
changes that give an organism an advantage
in a specific environment.” – Dr. Kevin
Anderson (Biochemist)
Evolutionists have to admit to begin with that
harmful mutations greatly outweigh
beneficial mutations in organism
One could rightfully question how the
overall species is supposed to move forward
when every step they take forward they have
to take fifty steps backwards
Left alone for long periods of time, wouldn’t
mutation kill something faster than it will
build something up?
Evolutionists like to focus on the beneficial
mutations that they do find, and so we will
focus on those too showing how even those
types of mutations are usually bad
The problem is those mutations are often
only beneficial in a very specific environment
And it usually hinders the organism from
functioning as effective as it had before in a
normal environment, it usually sacrifices
some sort of function to gain the upper hand
Lactose Intolerance
We are all familiar with the
problem that many have of
being lactose intolerant
(which is wrongly identified
as being allergic to milk)
People with this “problem”
lack the enzyme lactase,
which breaks down the milk
sugar lactose
This was (and still is) used as an example of
evolution and a beneficial mutation, people
who cannot drink milk are abnormal and the
people who can are more advanced
No one can doubt that the ability to drink
milk and use it for energy and nutrition is a
good thing today
But is it an example of the type of mutation
needed to cause large scale evolution?
“This is the best example of convergent
evolution in humans that I’ve ever seen,”
said geneticist Joel Hirschhorn, of the
Children’s Hospital Boston, Massachusetts
The problem is we now know this is not the
addition of something new (building
upward) but the destruction of something
that was already there to begin with
Everybody (mostly everybody) start off with
the ability to digest lactose as babies
After a few years in lactose intolerant
people, the production of lactase is turned
off by a regulatory system
People who can drink milk their whole life
without problems have a mutation that
makes this regulatory system not work
Is it beneficial? In an environment where
milk is available yes, in an environment
where it’s no available, no (because of the
energy used to produce lactase)
Despite the environment, it’s still a loss of
function, not a gain of function
This type of mutation cannot explain how the
enzyme lactase got there to begin with, and
how the regulatory system that stops its
production after a few years was created
It can only explain how it was damaged and
destroyed resulting in the ability to drink
milk (which is beneficial in our environment)
Sickle Cell Anemia
This mutation affects
the instructions that
code for the produce
hemoglobin
Hemoglobin carries
oxygen in your blood
The disease is recessive, and you only
develop if both parents have it (or are
carriers of the mutation)
How can sickle cell be seen as a beneficial
mutation for humans?
Those who have the disease are 50% less
likely to get malaria (seen in Africa)
If you’re in a malaria infested region without
any medical help to cure it, this could be
seen as a beneficial mutation
But under normal circumstances, you do not
(I repeat, you do not) want this disease
Sickle Cell Disease takes
down your life
expectancy quite a bit
You are much more
likely to have blood
clotting problems
These sickle cells only survive 1/6th the
average time of normal red blood cells, which
means you have a lacking number of red
blood cells and low energy from low oxygen
Beneficial mutation in Bubble Boy?
Some children are so prone to infection that
they spend their life inside a bubble to
protect themselves
This happens to those who have inherited
two copies of a defective gene which
produces an enzyme called ADA
(adenosine deaminase)
Because of this mutation, toxic substances
accumulate in their blood and damage the
bodies immune cells
However, one U.S. boy called Jordan
Houghton has suddenly recovered
All the evidence indicates that in one line of
his immune cells, one of the faulty genes has
apparently repaired itself because of a
mutation that happened
This is seen as a beneficial mutation (which
it is without a doubt) but the question again
would be, is this the type of thing that is
going to explain the origin of something?
It didn’t create anything new, it simply
corrected an error back to the original
This isn’t an example of a new function, but
an example of restoring an old function
Antibiotic Resistance
The most often cited example of a
beneficial mutation would be bacteria that
gain resistance to antibiotics
Bacteria can gain resistance through two
primary ways:
1. By mutation
2. By using a built-in design feature to swap
DNA (called horizontal gene transfer)
The second way is not our primary concern
here, because that is just swapping existing
information, which doesn’t explain the origin
of that information
The first way is by mutation, but there isn’t
just one type of mutation that can cause
antibiotic resistance, there are several
different mutations that we’ve observed that
gives different bacteria resistance
One example of
antibiotic-resistant
bacteria would be H.
pylori which have a
mutation that results in
the loss of information to
produce an enzyme
This enzyme in normal bacteria would
convert the antibiotic to a poison, which
causes the cell to die
Other examples would be antibiotics that
attach to certain parts of the cell, and
because of mutations in the cell that change
those structures and make it impossible for
the antibiotic to attached, the bacteria
survives and reproduces (and that trait by
natural selection takes over)
It’s important to note that it never creates a
new enzyme to fight the antibiotic, it
survives by loosing something
Georgia Purdom, Ph.D: “Antibiotic
resistance of bacteria only leads to a loss of
functional systems. Evolution requires a
gain of functional systems for bacteria to
evolve into man.”
When you take bacteria out of an
environment that has antibiotics (like a
hospital) it is less effective than the others
who did not develop that resistance. This
can’t possible cause evolution
Dr. John Sanford (Geneticist): “This is the
actual case, for example, in chromosomal
mutations that lead to antibiotic resistance
in bacteria, cell functions are routinely lost.
The resistance bacterium has not evolved. In
fact it has digressed genetically and is
defective. Such a mutant stain is rapidly
replaced by superior, natural bacteria as
soon as the antibiotic is removed. “
We need mutations that give a new feature,
not cripple an old one to survive
Herbicide Resistance
Many of us don’t like
having weeds in our yard
or garden, and use
herbicides to kill them
In one instance of a mutation, it was
demonstrated that a single nucleotide
substitution (a very small genetic change) in
the genome was responsible for resistance
to a weed-specific herbicide.
The way the weed gains resistance is similar
to the way antibiotics do, by having a slight
change in the area that the herbicide would
attach to (in order to kill the plant)
Again we must ask ourselves, is this the type
of mutation that we need to build a
molecular system in the first place?
We also don’t know if this is a mutation, it
could be a allele that was present already
(that’s a possibility with many “mutations”)
“Such a change has no selective value except
in the context of the man-made herbicide.
Even if originating from mutation (it could be
a rare neutral allele always present in the
population but springing into prominence
because of the use of the herbicide) this
would be no more than a neutral mutation;
not depriving the protein of its function but
neither creating a new function for it. So
where is the evolution?” - Dr. Maciej (head
of the Genetics Department of the PAS)
Peppered Moth
One example often used to support
evolution is the story about the grey or black
moths (Biston betularia) living on trees, the
population of moths changes colors as the
bark of the trees change color. They are
darker in industrial polluted environments,
and lighter in cleaner ones
This is a good example of natural selection,
but a bad example of a mutation
Why does this
shift in moth
color happen?
Is it evidence
of evolution as
often stated?
The answer is, moth dark and light color skin
alleles were all present before the pollution
and darkening of the trees occurred, but one
color survives better than the other
When the trees are
more white, the white
moths survive better
because the birds are
not able to see them
as well as the blacks
But when the trees start to darken, those
that have the black alleles (who would
originally have died quicker) are now the
ones surviving and reproducing (and
passing their dark trait on)
Mouse Skin Color Changes
Once upon a time
there was a
population of mice
that were put on a
white beach
After a while, they noticed these Mice (that
originally had darker hair) all became white
(albino) in color, and were able to better
survive by blending into the sand
No doubt that this mutation (or taking over of
an existing allele) was beneficial to the
survival of the mice, but again, how is
removing the production of pigmentation in
their fur an example of evolution?
What we need is an example of a mutation
that can create the system that produces
these pigments in organisms, not something
that stop them from being produced. Again
this is a downhill example
Wingless Beetles
Another example of
a “beneficial”
mutation that is
given is a population
of beetles that lost
it’s wings and
ability to fly
You may wonder how
loosing wings is
beneficial to beetles
The Island where these Beetles live is very
windy, and when they fly they die (in water)
We must ask ourselves once again, even if
this is beneficial for Beetles on a windy
island, is this how evolution works?
How can loosing your ability to fly explain
how you came about in the first place? All
these mutations can do is disable something
that is already in existence
What we need is an explanation on how the
wings got there in the first place
Fruit Flies
We have “sped
up” the process
of mutation in
organisms
before, the most
classic example is
fruit flies
We have created
thousands of mutations,
all of them are harmful
Why do we then assume that given enough
time a good one ill pop up naturally?
There are many other mutations that we
could look at that are given as examples of
beneficial and proof of evolution
Even if you found one or two truly beneficial
mutations that caused a new function, why
do you assume that they will out do the
thousands of harmful mutations that would
come about in the same time?
One step forward, thirty steps back will
never get you where you need to go
Memory Verse
Hebrews 3:4: “For every house is
built by someone, but the builder of
all things is God.”