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

Bacteria can gain resistance through two primary ways:

The most often cited example of a beneficial mutation would be bacteria that

gain resistance to antibiotics

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?

What we need is an explanation on how the wings got there in the first place

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

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.”