majority of individuals in practically all species show intermediate height, weight, and appearance. The range and distribution of traits remain approximately the same from generation to generation. This stabilizing influence is very common.

Some insects, birds, mammals, and other organisms practice "reverse discrimination" and prefer mates who are rare. The beautiful bird plumage in the Paradise Islands is a striking example. But that is the exception.

There is another very strong force for countering chance. Any large population of animals has a natural tendency towards stabilization. A solitary genetic contribution, even a beneficial one, is likely to be swall

Mutations: Facts and Figures

Let's start off where naturalists usually begin - with something like a bacteria. Never mind how those three million nucleotides got together and organized into a living system. Let's just say the bacteria-like life form is a given.

How is the bacteria suppose to change? Answer: by mutation. Immediately we run into a problem. Mutations are very rare. Even more discouraging, the simpler the organism, the fewer the mutations. And nothing alive is more simple than a one-celled bacteria type of organism.

On the average, one mutation would show up in every 500,000 of these creatures. That's a slow start. But coming up with a mutation is only the first of many hurdles. The second hurdle is finding a beneficial mutation. (See: Those Elusive Beneficial Mutations.) Geneticists claim 0.1 per cent of them are beneficial. Okay, lets go with it.

Cranking out the numbers shows that on the average one out of every 500,000,000 (500,000 X 1,000) single-celled organisms may have a beneficial mutation. Which brings to question: How long did it take these life forms to build up to a population of 500,000,000?

Evolution by mutation is full of hazards and complications. Here is one: Most animals don't live long enough to reproduce. Something, usually another animal, comes along and kills them before they reach maturity.

Infant mortality varies greatly from species to species. We know that as far as sea creatures go, only a few, just a small percentage, survive to mate. In general, the smaller the creature, the less chance it has to make it to adulthood. How does that affect evolution? It simply adds another hurdle to the list.

All mutations are rare; much rarer are the positive mutations. Now we see that the majority, probably the vast majority of those already extremely rare mutations are dead on arrival. Predators, disease, fire, drought, famine, floods, and other natural disasters destroy them before they have an opportunity to pass on their innovative trait.

Let's think positively. Say we have a one in five hundred million positive mutant who avoids predators, disease, etc. Is he able to pass on his positive mutation? Not necessarily.

Many mature males are barred from finding a mate due to a local dominant male who keeps all available females for himself. That is true for seals, antelopes, baboons, and many other mammals. Obviously, if the positive mutation winds up in a male who can't mate, the beneficial trait will go no further.

Any other roadblocks? Yes, most animal populations are genetically stable. Why? Mates with medium characteristics or traits are favored, while those with unusual traits are shunned. So the majority of individuals in practically all species show intermediate height, weight, and appearance. The range and distribution of traits remain approximately the same from generation to generation. This stabilizing influence is very common.

Some insects, birds, mammals, and other organisms practice "reverse discrimination" and prefer mates who are rare. The beautiful bird plumage in the Paradise Islands is a striking example. But that is the exception.

There is another very strong force for countering chance. Any large population of animals has a natural tendency towards stabilization. A solitary genetic contribution, even a beneficial one, is likely to be swallo

is only the first of many hurdles. The second hurdle is finding a beneficial mutation. (See: Those Elusive Beneficial Mutations.) Geneticists claim 0.1 per cent of them are beneficial. Okay, lets go with it.

Cranking out the numbers shows that on the average one out of every 500,000,000 (500,000 X 1,000) single-celled organisms may have a beneficial mutation. Which brings to question: How long did it take these life forms to build up to a population of 500,000,000?

Evolution by mutation is full of hazards and complications. Here is one: Most animals don't live long enough to reproduce. Something, usually another animal, comes along and kills them before they reach maturity.

Infant mortality varies greatly from species to species. We know that as far as sea creatures go, only a few, just a small percentage, survive to mate. In general, the smaller the creature, the less chance it has to make it to adulthood. How does that affect evolution? It simply adds another hurdle to the list.

All mutations are rare; much rarer are the positive mutations. Now we see that the majority, probably the vast majority of those already extremely rare mutations are dead on arrival. Predators, disease, fire, drought, famine, floods, and other natural disasters destroy them before they have an opportunity to pass on their innovative trait.

Let's think positively. Say we have a one in five hundred million positive mutant who avoids predators, disease, etc. Is he able to pass on his positive mutation? Not necessarily.

Many mature males are barred from finding a mate due to a local dominant male who keeps all available females for himself. That is true for seals, antelopes, baboons, and many other mammals. Obviously, if the positive mutation winds up in a male who can't mate, the beneficial trait will go no further.

Any other roadblocks? Yes, most animal populations are genetically stable. Why? Mates with medium characteristics or traits are favored, while those with unusual traits are shunned. So the majority of individuals in practically all species show intermediate height, weight, and appearance. The range and distribution of traits remain approximately the same from generation to generation. This stabilizing influence is very common.

Some insects, birds, mammals, and other organisms practice "reverse discrimination" and prefer mates who are rare. The beautiful bird plumage in the Paradise Islands is a striking example. But that is the exception.

There is another very strong force for countering chance. Any large population of animals has a natural tendency towards stabilization. A solitary genetic contribution, even a beneficial one, is likely to be swall

ch maturity.

Infant mortality varies greatly from species to species. We know that as far as sea creatures go, only a few, just a small percentage, survive to mate. In general, the smaller the creature, the less chance it has to make it to adulthood. How does that affect evolution? It simply adds another hurdle to the list.

All mutations are rare; much rarer are the positive mutations. Now we see that the majority, probably the vast majority of those already extremely rare mutations are dead on arrival. Predators, disease, fire, drought, famine, floods, and other natural disasters destroy them before they have an opportunity to pass on their innovative trait.

Let's think positively. Say we have a one in five hundred million positive mutant who avoids predators, disease, etc. Is he able to pass on his positive mutation? Not necessarily.

Many mature males are barred from finding a mate due to a local dominant male who keeps all available females for himself. That is true for seals, antelopes, baboons, and many other mammals. Obviously, if the positive mutation winds up in a male who can't mate, the beneficial trait will go no further.

Any other roadblocks? Yes, most animal populations are genetically stable. Why? Mates with medium characteristics or traits are favored, while those with unusual traits are shunned. So the majority of individuals in practically all species show intermediate height, weight, and appearance. The range and distribution of traits remain approximately the same from generation to generation. This stabilizing influence is very common.

Some insects, birds, mammals, and other organisms practice "reverse discrimination" and prefer mates who are rare. The beautiful bird plumage in the Paradise Islands is a striking example. But that is the exception.

There is another very strong force for countering chance. Any large population of animals has a natural tendency towards stabilization. A solitary genetic contribution, even a beneficial one, is likely to be swall

>Let's think positively. Say we have a one in five hundred million positive mutant who avoids predators, disease, etc. Is he able to pass on his positive mutation? Not necessarily.

Many mature males are barred from finding a mate due to a local dominant male who keeps all available females for himself. That is true for seals, antelopes, baboons, and many other mammals. Obviously, if the positive mutation winds up in a male who can't mate, the beneficial trait will go no further.

Any other roadblocks? Yes, most animal populations are genetically stable. Why? Mates with medium characteristics or traits are favored, while those with unusual traits are shunned. So the majority of individuals in practically all species show intermediate height, weight, and appearance. The range and distribution of traits remain approximately the same from generation to generation. This stabilizing influence is very common.

Some insects, birds, mammals, and other organisms practice "reverse discrimination" and prefer mates who are rare. The beautiful bird plumage in the Paradise Islands is a striking example. But that is the exception.

There is another very strong force for countering chance. Any large population of animals has a natural tendency towards stabilization. A solitary genetic contribution, even a beneficial one, is likely to be swall

majority of individuals in practically all species show intermediate height, weight, and appearance. The range and distribution of traits remain approximately the same from generation to generation. This stabilizing influence is very common.

Some insects, birds, mammals, and other organisms practice "reverse discrimination" and prefer mates who are rare. The beautiful bird plumage in the Paradise Islands is a striking example. But that is the exception.

There is another very strong force for countering chance. Any large population of animals has a natural tendency towards stabilization. A solitary genetic contribution, even a beneficial one, is likely to be swallowed up in a massive gene pool. In the long run, all mutations - good or bad - have no affect on a large population. That is why herd animals remain so constant.

Scientists call it genetic homeostasis. The only place where any mutation stands a chance of surviving is in a small, isolated, peripheral population.

All of this throws a wrench into evolution's gears. Mutations of any sort are rare; mutations which might help evolution are much rarer still; and the bearer of those good-for-evolution mutations are likely to be destroyed by "mother nature" before the innovation can be passed on.

Even if the animal survives to mate, the odds are against his offspring living long enough to permanently establish the new trait in the gene pool. If the bearer is a male, chances are the positive mutation will go no further unless he happens to be the dominate male in the area.

If one of those ever so rare positive mistakes hits a large population, it sinks without a trace. Even if the beneficial mutation winds up in a not-so-large gene pool, the animals will more than likely consider it extreme and discriminate against it.

We will continue our study with an analogy of evolution by mutation called "The Language of Life": see Evolution:The Devil Is in the Details (Part Five of Six.)