Natural Selection or Luck

[Micaiah]

Today at 06:17 AM Tawhano said this in Post #118

Here’s something I have always wonder about concerning natural selection that maybe someone here can clarify it for me. I remember watching a documentary about a species of plant (sage?) that only grew on one particular island. This island was where a species of sea turtles go to lay their eggs. The sea turtles would come on shore, exhausted, and eat the plants. The results of this were that the top of the plants would be eaten down to ground level on the entire bed of plants. The plants survive because unlike other similar species their seeds were buried underground. How can this be explained in regards to the theme of this thread?
If evolution takes such a long period of time wouldn’t the species have died out before the mutation of burying its seeds underground took hold and spread throughout the population? Also, was it the plant that decided to bury it’s seeds underground or just a fluke of mutation?

Interesting point. I'd like to give it some more consideration.

 

[Gracchus]

Today at 04:36 PM Micaiah said this in Post

#120
In the examples you gave, the genes for say height or hairiness considered will exist in certain populations in significant numbers. That is different to the case we are considering where a single copying error occurs. In this case, there may be only one in the entire population.

In the case of one mutation, chance would play a big, perhaps major part, in determining whether the gene would become fixed.

Incidentally, ratio of animals with a certain gene is calculated from the number of animals with the gene. These are different ways of expressing the same thing mathematically.

The ratio is the number with the gene to the number in the whole breeding population.

For evolution to be true, these copying errors must be able to add new information to the animals DNA, and it must result in a beneficial mutation. The importatnce of these assumptions is seen by considering the theorised evolution from bacteria to human.

In fact, if reduplicated DNA suffers a point mutation, new information is added. Evolution can also occur without such constraints. However the loss of a possible allele, which is to say, a decrease in variability, is also an increase in information.

The problem is there are no known cases where these two assumptions have been known to occur. I have assumed them correct correct for the purposes of our discussion.

Increases in information and beneficial mutations are known to occur. Where did you ever get the idea that this never happens?

Statistical analysis is carried out in a range of real applications, and the results are used in decision making. I understand that industrial geneticists use calculations to assist in their research.

That may indeed be true, but my point was that evolution, like the weather, exhibits extreme sensitivity to initial conditions. Not only may the significance of the conditions be indeterminable, but the overall effect of change may be unpredictable.

 

[Micaiah]

Today at 06:17 AM Tawhano said this in Post #118

Here’s something I have always wonder about concerning natural selection that maybe someone here can clarify it for me. I remember watching a documentary about a species of plant (sage?) that only grew on one particular island. This island was where a species of sea turtles go to lay their eggs. The sea turtles would come on shore, exhausted, and eat the plants. The results of this were that the top of the plants would be eaten down to ground level on the entire bed of plants. The plants survive because unlike other similar species their seeds were buried underground. How can this be explained in regards to the theme of this thread?
If evolution takes such a long period of time wouldn’t the species have died out before the mutation of burying its seeds underground took hold and spread throughout the population? Also, was it the plant that decided to bury it’s seeds underground or just a fluke of mutation?

I don't know enough about the plant in question to comment on its geographic origins, and any possible adaptation that may have occured. Any idea of the plants name. I'm sure the evolutionists will find a way to explain its method of propagation. I'll leave it to them.

I am a Christian who believes that the account given in Genesis is historically correct. The plants and animals were created by God, each after their own kind. We know that life forms have the ability to adapt to their environment within the constraints of the particular kind. That demonstrates God's creative intelligence.

The case of the sea turtle and plants show the co-dependence and harmony that exists in nature.

 

[Micaiah]

Today at 12:43 PM Gracchus said this in Post #122



In the case of one mutation, chance would play a big, perhaps major part, in determining whether the gene would become fixed.

I agree. Could you explain this to some of your colleagues who suggest that chance has a minimal impact on survival, and survival of the fittest is always occurs.

The ratio is the number with the gene to the number in the whole breeding population.

Agreed.

In fact, if reduplicated DNA suffers a point mutation, new information is added. Evolution can also occur without such constraints. However the loss of a possible allele, which is to say, a decrease in variability, is also an increase in information.

We could liken the DNA of an animal to text in a book. The DNA contains a lot of meaningful and functional information. Adding pages of gibbereish to a book doesn't mean you have added information to a book. Adding an extra page of the same information in a book doesn't mean you have added information. Adding an Epilogue to a book is adding information.

Increases in information and beneficial mutations are known to occur. Where did you ever get the idea that this never happens?

I have asked for exampes in the past and haven't got any that meet the requirements given above. Antibiotic resistant strains of bacteria, and tuskless elephants result from a loss of information or sensitivity.

That may indeed be true, but my point was that evolution, like the weather, exhibits extreme sensitivity to initial conditions. Not only may the significance of the conditions be indeterminable, but the overall effect of change may be unpredictable.

The calculation relating chance of survival to population ratios would be useful here.

 

[anon5354]

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<TD vAlign=top>Micaiah

The thing is that there are many other ways to create gentical variation. It is true that mutation is not frequent. It is also not considered to be a major evolutionary force in microevolution, just like the situation you discribe of a hypothetical animal &nbsp;population. Sexual recombination, genetic drift will be the main variation component. In plants you may also consdier polyloidy. The organism with the most favourable allele will survive and be selected. Its advantage&nbsp;will then propagate through its offsprings.

For evolution and mutation to truely work, you cannot have static or "stable" population or a constant environment. You will also need a big population. Alleles may not be benefitial in some case (such as the gene for sickle cell anemia) until the right environment (this gene also help preventing malaria) so long as it remain heterozygous recessive. So whether a mutation is benefitial depends on the enviornment as well.

In your hypothetical situation. the 0.02% increase in survival rate will magnify over many generations. YOu have to also take into&nbsp;account that having survival&nbsp; advantage will mean less for others in the same species due to competition for the same food source. Competitive exclusion ouccurs. Your better suriving&nbsp;line will then compose&nbsp;a mjor portion&nbsp;of the pop. of its species after many generations. And if another benefitial mutation occurs, the same will repeat. Of course in such static situation it will take very long time for significant&nbsp;character displacement. THerefore you must also consider sexual recombination, which would suffle the genes with other and may contribute in a better combination and gives it additional survival advantage. YOu must also consider taht&nbsp;evolution occurs only when the environment is changing, causing more mutations wiping out less favourable traits and&nbsp;allowing the favourable one to grow.

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