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Live in Louisiana?
© Garry Trudeau's take on education in that state.

copyright G B Trudeau

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Text: Copyright GWBAA

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Chapter Three: God the Creator?

Section 5: Evolution

Only evolution, supported by overwhelming evidence from biology, chemistry and geology, offers a credible explanation for the development of life.

pic: the evolution from land animals to whales:
click on the pic for more information

What's wrong with evolution? Why are Creationists and proponents of Intelligent Design so hostile to it?

3.5a Apes and watches

Some people object on intellectual grounds - there are areas of evolutionary theory that are not yet fully understood and opponents use these uncertainties to deny evolution as a whole.

Some believers assert that evolution denies the existence of the Christian or Muslim God; they argue that because God exists, evolution is false. (However, many believers accept the principle of evolution.)

Some consider that it is somehow shameful to share a genetic past with monkeys and apes. "Evolution must be false, because I won't accept that I'm a monkey." (In fact no evolutionist claims that human beings are descended from apes; they are our cousins, not our parents).

Some are convinced by the watchmaker argument, first proposed by William Paley in 1802. Because it's impossible to throw bits

Explaining the Universe

Jews, Christians and Muslims insist that God created the universe. In both philosophical and practical terms, however, that theory turns out to be unsustainable.

3.1: God the Created?
Where did God come from?

3.2: The balanced universe
Improbable is not impossible

3.3: Creationism
Holes in Noah's Ark

3.4: Intelligent design
False assumptions and faulty reasoning

3.5: Evolution
Reproduction, mutation and environment

3.6: Summary

Finished this chapter? Move on to

Chapter 4
Why people believe

If God does not exist, why do so many people believe in him?

There are many reasons, from the strength of community to fear of death.

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of metal into the air and expect that chance will assemble them into a watch as they fall to the ground, it's equally impossible to expect even more complex phenomena, such as human beings, to evolve through chance. Since watches are the product of conscious design (by humans), humans must be the product of conscious design (by God).

We will come back to the "evolution-or-God" argument and to uncertainties in evolution later on this page. The "I'm not a monkey" statement is pure emotion and does not deserve a response - except perhaps to say that those who stand by it seem to have the same reasoning powers as monkeys.

How about the watchmaker argument? It's true that watches don't come into existence by chance, but the analogy is false. No-one is suggesting that humanity or any other lifeform evolved by chance alone. Chance does play a small part in evolution but other factors are also important.

So let us set aside misconceptions and prejudices and ask ourselves what evolution really is. It is true that the topic is complicated and we will only be able scratch the surface, but the basic principles are simple and easy to understand.

For responses to other misconceptions around evolution
see this UC Berkeley webpage

3.5b Then there was life

The earth formed from cosmic debris about 4.5 billion years ago and rudimentary life began to appear about 500 million years later. (Creationists claim that the world is less than 10,000 years old, but that's a separate discussion.)

The exact process by which life emerged is not yet fully understood. It is likely that at some point in the earth's early history protein chemicals, stimulated by heat, lightning, other chemicals, radioactivity in the atmosphere or some other factor, combined to form the basic building block of life, ribonucleic acid (RNA). This may not have been a unique event, but might
pic: folded "hairpin": a type of RNA substructure
have occurred several times before lifeforms became permanently established on this planet.

The appearance of life was not a miracle; scientists expect to be able to replicate it in the laboratory within the next generation. (For a more detailed overview of the origins of life, consult this Wikipedia article.)

3.5c Reproduction and mutation

It needs several years of study to fully understand the specifics of RNA, its successor DNA and how they underpin every lifeform from viruses to human beings. But it is easy to understand the basic principles of evolution – reproduction, mutation and environment. These principles the origins of all living things, no matter how simple or complex.

Life implies not only death, but reproduction; all lifeforms reproduce. The simplest organisms divide to form offspring while the offspring of complex organisms combine traits from two parents.

Reproduction is not perfect. Every so often something interferes in the process. In single-celled organisms this may be a factor such as different chemicals in the atmosphere or a slightly higher or lower temperature. In mammals the foetus is highly sensitive to its
pic: chromosomes splitting
and mutating
environment - the mother's general health, hormone levels, the food she eats etc. A change may occur, with offspring slightly different from its parent, perhaps with a molecule or chromosome too few or too many or in the wrong place. A mutation has occurred.

Mutations are both rare and frequent. Rare, in that most reproduction does not lead to any change. Frequent, in that there are so many reproductions that mutations are always occuring - even if mutation occurs only once in a million reproductions, that still means that billions of billions of billions of mutations have occurred since life began.

A mutation can take any form. It may be so gross that the organism does not survive (for example, the heart malforms), or so minor that it is not noticed (for example, slightly longer ears). But

A mutation that leads a bird to develop less efficient wings makes it less likely that the bird will survive and have descendants. Such a mutation can be described as negative. Mutations which make survival easier – such as more efficient wings or a stronger sense of smell to seek out food – enable a life-form to live longer and pass on the mutation to its descendants. Such mutations can be described as positive - and because they help the lifeform to survive, positive mutations are likely to be passed on generation after generation.

In evolutionary terms, the only important mutations are those which affect the organism’s ability to survive.

Science fiction and horror stories lead many people to consider the idea of mutation as always negative or harmful. In evolutionary terms, however, a mutation may have a positive impact, a negative impact or no impact at all; the word means only that the offspring of a lifeform differs in some way from its parent(s).

3.5d Environment

We know that mutations which make survival easier are more likely to be passed to a lifeform's descendants. To that knowledge we must add the observation that survival is a function of environment - that means that mutations have a positive or negative impact depending on the lifeform's environment. For example the mutation that led to the development of dorsal fins was positive for fish, but it would severely reduce a cheetah’s or ape’s mobility.

Every life-form is part of the environment for other life-forms, which means that a mutation in one affects many others. For example, mutations in bone structure and muscular tissue have led to antelopes developing the ability to run fast enough to escape from lions most of the time, while other mutations in bone structure and muscular tissue have enabled lions to evolve to sometimes run fast enough to catch antelopes to eat.

This combination of reproduction, mutation and environment can also be described as natural selection. (This is, however, an unfortunate term, because "selection" implies a consciousness which selects and the process takes place without any consciousness.)

3.5e Complexity and sex

So far, so good. We have covered the general principles of evolution, but we haven't directly answered the point frequently raised by creationists - how did complex structures such as the human form evolve from much simpler structures such as single-celled organisms without the intervention of a designer?

The answer is simple. Single-celled organisms reproduce by dividing. Mutation means that every so often a division failed. Most times, the mutated double-celled organism would die, unable to survive in its environment, but at least once - and perhaps many times - a new double-celled life form survived, taking the first critical step towards complexity.

These new organisms reproduced and at some point double-celled organisms become multi-celled and ever more complex.

The next important process was sex. How did reproduction by division, where an offspring had a single parent, become reproduction through sex, with two parents? Sex is important because inheriting the characteristics, together with possible mutations, from two parents gives many more opportunities for offspring forms to adapt to and profit from their environment.

Current research indicates that the mutation(s) which
pic: Origins of Sex by L Margulis and D Sagan gametes - cells whose nucleus unites with the nucleus of other cells to form a new organism
led to new combinations of genes in single-cell organisms occurred about three billion years ago. That meant offspring had a single parent, but there could be significant variations between the components of offspring and parent.

Perhaps another billion years passed before a bacterium, which was hosted by one single-cell organism, moved to another single-celled organism, bringing their original host’s genes with them. This was not sex in the modern sense of the word, where one body injects genetic material into another - but it was the frist time that an offspring combined the genes of two parents. (The fact that

As the opportunities for new mutations grew, cells began to specialize in different skills such as mobility and digestion. The cumulative impact of different mutations in different environments allowed species as different and complex as spiders, duck-billed platypuses and human beings to emerge.

For other theories of the origins of sex, see this Wikipedia article

3.5f It takes time

This long, complex, hit-and-miss process that we call evolution depends on one key factor: time. Human history stretches back only five thousand years and only in the last three hundred years has science developed to any great extent. Compared to the planet’s history, our experience adds up to less than an inch in a one-mile race. We are watching a film that appears to have paused but in reality the image is changing at a pace that would take us thousands of generations to notice.

That means we have seen very little evolution in action. We can observe the wings of moths lightening or darkening depending on pollution in the atmosphere. We can see and influence genetic changes in fruit-flies or fish in different environments, but we can't directly observe long-term changes such as those which led birds to evolve from reptiles or the slow evolution of today's humanity, homo sapiens, from our predecessors homo ergaster two million years ago.

That does not mean that these changes did not occur. We cannot observe evolution directly but we can look at the evidence around us. From fossils to genes we are beginning to piece together the development of life-forms on this planet. The record is incomplete and not every detail is clearly understood. Nevertheless it is clear that evolution is the only explanation that fits all the available facts.

3.5g Uncertainties and problems

Does evolution tell us everything we know about the origins and development of life on this planet? No. Just as astronomy still gives us an incomplete picture of the cosmos and physics cannot yet explain how different phenomena such as gravity and general relativity interact, our knowledge of evolution is incomplete.

Does that mean that evolution is false? No, uncertainties in evolution, like uncertainties in astronomy or physics, do not undermine the overall principle; they only point us towards areas where we need more research. We may not know, for example, exactly how life or sex began - but our ignorance is proof only of how much we still have to learn, it is not proof of God's existence.

Want to know more? Click the following sites for a basic introduction to evolution.
UC Berkeley      HowStuffWorks      Wikipedia

3.5h Evolution and God

Are God and evolution mutually exclusive? Many believers accept evolution and some evolutionary scientists believe in God - they argue that God triggered evolution but otherwise let it progress exactly as scientists have defined.

But the "evolution-and-God" theory suffers from an intrinsic flaw. If God created the human soul, at some point in our prehistory he "inserted" the soul into one or more individuals. Those individuals became immortal, but their parents did not. While alive, did those with souls become aware of their intrinsic difference from their parents? After death, did they wonder why their parents did not join them in Heaven or Hell - and if so, what did God tell them?

This point is irrelevant for non-believers but is important for those who want both God and evolution in their lives. The ultimate absurdity of the question, however, which implies that at one point in prehistory a primate-with-no-soul gave birth to a human-with-a-soul, leads many people to the conclusion that God and evolution are incompatible.

3.5i The best there is

When we compare the relative merits of creationism, intelligent design and evolution, it is clear that only evolution, supported by overwhelming evidence from biology, chemistry and geology, offers a credible explanation for the development of life.

What's next? Choose from

Chapter Three: Summary Chapter Four: Why people believe

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If God existed, he would...

admire the beauty of a universe that he did not create

recognize that eternity is meaningless

deny both heaven and hell

disown all men and women who speak in his name

denounce the harm caused by religious "morality"

help the human race to thrive without him

If God existed, he would be an atheist.

What is the difference between science and faith?

science is certain of nothing and requires proof of everything

faith is certain of everything and requires proof of nothing

Which do you trust?

"I know there is no God"
"I believe there is no God"

Check the answer

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