Evolution Pros and Cons

[freeztar]

Moon, let me put it another way. How do you explain such diversity in fossil strata? If the animals in the layer were all exposed to a similar environment, why wouldn't they develop similar traits? Why would some eat meat and others grass? Why would some grow wings and others grow horns? Do their genes have some kind of signal mechanism that says.. I need wings, let's grow some?

 

Those are good questions questor.

The short answer is that different organisms occupy different ecological niches combined with the evolutionary processes of natural selection, genetic drift, and population isolation->speciation.

 

Imagine this scenario from, say, 100 mya in Australia. A species of frog adapted to living in the rainforest undergoes a population explosion (perhaps because of many good years of rain or food, or an extinction of one of their top predators). Resources are always a limiting factor, so the frogs compete heavily for food, mating grounds, etc. Some frogs venture to the outskirts of the rainforest to take advantage of untapped resources (new food sources, etc.). Some of these frogs die because they cannot deal with the new environmental factors (new food sources, change in micro-climate, inadequate breeding grounds, etc.). But, some of these frogs survive due to a different genetic makeup/fitness that allows them to tolerate these new environmental conditions. These frogs reproduce and through time begin to adapt better to their new home. Fast forward 50 million years and analyze a frog from the center of the rainforest, and those on the edge. You might find that the frogs in the interior have retained much of their morphology and even genetics, whereas those frogs on the outskirts have changed their morphology/genetics to better adapt to their new environment. (they might have less webbing on their feet due to drier conditions, or maybe they adapted poisons to deal with the new predators, etc.)

 

This is a very simple thought experiment that is meant to illustrate how speciation occurs. When you figure in the complex web of life, it is easy to see how complicated it can get.

 

Also, it's important to realize that 50 million years is a *long* time. Scientists today can invoke adaptations in microorganisms in far less time than an average human lifetime. When you multiply this out to something like 50 million years, the possibilities become staggering.

By the way, can you give an example of a succesful mutation that can be heritable?

 

I believe you are referring to germ line mutations.

As MTM noted earlier in this thread, the vast majority of hereditary mutations are not beneficial. For a list of some beneficial mutations, check out the following link.

 

Examples of Beneficial Mutations and Natural Selection

[Galapagos]

I believe you are referring to germ line mutations.

As MTM noted earlier in this thread, the vast majority of hereditary mutations are not beneficial. For a list of some beneficial mutations, check out the following link.

 

Examples of Beneficial Mutations and Natural Selection

 

You mention above that scientists can observe evolution occurring in microbes due to their short generations. This reminded me of the excellent example put forth by Lenski et al earlier this year, as published in the PNAS, and covered extensively in various media outlets:

Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli ? PNAS

The role of historical contingency in evolution has been much debated, but rarely tested. Twelve initially identical populations of Escherichia coli were founded in 1988 to investigate this issue. They have since evolved in a glucose-limited medium that also contains citrate, which E. coli cannot use as a carbon source under oxic conditions. No population evolved the capacity to exploit citrate for >30,000 generations, although each population tested billions of mutations. A citrate-using (Cit+) variant finally evolved in one population by 31,500 generations, causing an increase in population size and diversity. The long-delayed and unique evolution of this function might indicate the involvement of some extremely rare mutation. Alternately, it may involve an ordinary mutation, but one whose physical occurrence or phenotypic expression is contingent on prior mutations in that population. We tested these hypotheses in experiments that “replayed” evolution from different points in that population's history. We observed no Cit+ mutants among 8.4 × 1012 ancestral cells, nor among 9 × 1012 cells from 60 clones sampled in the first 15,000 generations. However, we observed a significantly greater tendency for later clones to evolve Cit+, indicating that some potentiating mutation arose by 20,000 generations. This potentiating change increased the mutation rate to Cit+ but did not cause generalized hypermutability. Thus, the evolution of this phenotype was contingent on the particular history of that population. More generally, we suggest that historical contingency is especially important when it facilitates the evolution of key innovations that are not easily evolved by gradual, cumulative selection.

 

The Loom : A New Step In Evolution

http://www.nytimes.com/2007/06/26/science/26lab.html?ex=1184299200&en=72de3b507cf9d4c6&ei=5070

[Zythryn]

The evolutionist author Roger Lewin expresses the thermodynamic impasse of evolution in an article in Science:

 

One problem biologists have faced is the apparent contradiction by evolution of the second law of thermodynamics. Systems should decay through time, giving less, not more, order.366

 

Questor, this is a partial quotation. For the full context perhaps you should read, or include if you already read it, the second part:

One legitimate response to this challenge is that life on earth is an open system with respect to energy and therefore the process of evolution sidesteps the law's demand for increasing disorder with time.

 

This is from Science, September 1982 Volume 217.

Now, this is the only one I checked, will we find similar errors if we can actually find the sources of the quotes for the others?

 

Your source of information is in error and is either intentionally trying to mislead you, or was mislead themselves.

[ughaibu]

This indicates that out of the thousands of fossils, two transitional were found?

You're joking, I hope.

Is there any line of succession we can follow either backward or forward?

The cliche is horses. Really, surely everybody came across this before they were ten years old.

[questor]

The change of the beaks of the finches only shows that changes can occur in species, NOT create a new species.

 

Ugh, if you are referring to an eohippus evolving to a modern horse the same as above applies to it.

 

The crux here is the claim that all species evolved from a single cell life form.

[ughaibu]

The crux here is the claim that all species evolved from a single cell life form.

This is what you want transitional fossils for?

[questor]

While experiments can show benign mutation for gut improvement, does the research demonstrate a microorganism becoming any other form of life? If mutations can change speciation, do we have some examples existing now where this has happened? Surely now we should have evidence of some new creatures formed by mutations started centuries ago.

[ughaibu]

You're aware of endosymbiosis(?)

[questor]

''You're aware of endosymbiosis(?)'' I am now, and the thought occurs to me that this process should be creating new species of life constantly. Or, by using this information new species should be relatively easy to create in the lab. If endosymbiosis is a common occurrence there should be numerous new life forms appearing at all times. Would you agree?

[Thunderbird]

''You're aware of endosymbiosis(?)'' I am now, and the thought occurs to me that this process should be creating new species of life constantly. Or, by using this information new species should be relatively easy to create in the lab. If endosymbiosis is a common occurrence there should be numerous new life forms appearing at all times. Would you agree?

The fossil record shows new species appear and disappeared quite regularly over millions of years. The most resent of these are hominids and bats.

[questor]

Yes, species go extinct regularly. Does this have something to do with evolution?

What were hominids before they became hominds? Lemurs? Bats?

[Thunderbird]

Yes, species go extinct regularly. Does this have something to do with evolution?

What were hominids before they became hominds? Lemurs? Bats?

 

Read learn Great ape - Wikipedia, the free encyclopedia

[Pyrotex]

While experiments can show benign mutation for gut improvement, does the research demonstrate a microorganism becoming any other form of life? If mutations can change speciation, do we have some examples existing now where this has happened? Surely now we should have evidence of some new creatures formed by mutations started centuries ago.

You toss around the phrase "form of life" as if you know what you were talking about. Evolving a gut improvement doesn't appear to be a "new" form of life in your opinion. So, what IS required for a "form of life" to be "new"? What is the minimum difference required to distinguish between two different "forms of life"? IYNSHO.

 

Nature does not distinguish between "forms of life". Nature does not distinguish or recognize "species". All of our categorization schemes are just that--categorization schemes, that we invented, as an aid to our understanding. There is NO genetic "switch" or "marker" that identifies or distinguishes among "species".

 

So any conversation about "new forms of life" must begin by acknowledging that the definitions for "form of life" and "new" are entirely arbitrary.

 

Technically speaking, every living creature on Earth (excepting those that clone themselves) is a "new form of life" because it is genetically unique.

[questor]

Pyrotex, since you obviously cannot discuss issues with me on a polite basis, I think it best not to communicate with you since it usually leads to my banishment.

If someone else would ask me this question, I would say that ultimately life forms can be described and grouped by their dna and genomes.

[Pyrotex]

Pyrotex, since you obviously cannot discuss issues with me on a polite basis, I think it best not to communicate with you since it usually leads to my banishment....

I always start ALL my discussions on a very polite basis.

It's just that I have very highly trained Prevarication & Dissembling Detectors (PDDs) -- and you keep tripping them, for some strange reason. :)

Remember, I grew up with relatives and preachers who sounded just like you, and who attempted to "pass off" pulpit logic as scientific logic, just like you. In fact, questor, had it not been for the grace of some god or another, I would have grown up thinking exactly like you. So, it should come as no surprise that I take a special interest in you. You're like my long-lost evil twin Skippy.

But you're not really "evil"--you're just infected with a toxic meme.

And I want to "heal" you, and bring you back into the light of truth and reason.

 

C'mon, ques, gimme a big hug... :)

[questor]

Perhaps a biochemist could shed some light on these observations:

''When it addresses this question, evolutionary theory claims that life started with a cell that formed by chance. According to this scenario, four billion years ago various chemical compounds underwent a reaction in the primordial atmosphere on the earth in which the effects of thunderbolts and atmospheric pressure led to the formation of the first living cell.

 

The first thing that must be said is that the claim that nonliving materials can come together to form life is an unscientific one that has not been verified by any experiment or observation. Life is only generated from life. Each living cell is formed by the replication of another cell. No one in the world has ever succeeded in forming a living cell by bringing inanimate materials together, not even in the most advanced laboratories.

 

The theory of evolution claims that a living cell-which cannot be produced even when all the power of the human intellect, knowledge and technology are brought to bear-nevertheless managed to form by chance under primordial conditions on the earth. In the following pages, we will examine why this claim is contrary to the most basic principles of science and reason.''

''One of the basic reasons why the theory of evolution cannot explain how the cell came into existence is the "irreducible complexity" in it. A living cell maintains itself with the harmonious co-operation of many organelles. If only one of these organelles fails to function, the cell cannot remain alive. The cell does not have the chance to wait for unconscious mechanisms like natural selection or mutation to permit it to develop. Thus, the first cell on earth was necessarily a complete cell possessing all the required organelles and functions, and this definitely means that this cell had to have been created.''

'' Proteins are giant molecules consisting of smaller units called amino acids that are arranged in a particular sequence in certain quantities and structures. These units constitute the building blocks of a living protein. The simplest protein is composed of 50 amino acids, but there are some that contain thousands.

 

The crucial point is this. The absence, addition, or replacement of a single amino acid in the structure of a protein causes the protein to become a useless molecular heap. Every amino acid has to be in the right place and in the right order. The theory of evolution, which claims that life emerged as a result of chance, is quite helpless in the face of this order, since it is too wondrous to be explained by coincidence. (Furthermore, the theory cannot even substantiate the claim of the accidental formation of amino acids, as will be discussed later.)

 

The fact that it is quite impossible for the functional structure of proteins to come about by chance can easily be observed even by simple probability calculations that anybody can understand.

 

For instance, an average-sized protein molecule composed of 288 amino acids, and contains twelve different types of amino acids can be arranged in 10300 different ways. (This is an astronomically huge number, consisting of 1 followed by 300 zeros.) Of all of these possible sequences, only one forms the desired protein molecule. The rest of them are amino-acid chains that are either totally useless, or else potentially harmful to living things.

 

In other words, the probability of the formation of only one protein molecule is "1 in 10300. "The probability of this "1" actually occurring is practically nil. (In practice, probabilities smaller than 1 over 1050 are thought of as "zero probability").

 

The complex 3-D structure of the protein cytochrome-C. The slightest difference in the order of the amino acids, represented by little balls, will render the protein nonfunctional.''

'' Evolutionists claim that molecular evolution took place over a very long period of time and that this made the impossible possible. Nevertheless, no matter how long the given period may be, it is not possible for amino acids to form proteins by chance. William Stokes, an American geologist, admits this fact in his book Essentials of Earth History, writing that the probability is so small "that it would not occur during billions of years on billions of planets, each covered by a blanket of concentrated watery solution of the necessary amino acids."242

''If the coincidental formation of even one of these proteins is impossible, it is billions of times "more impossible" for some one million of those proteins to come together by chance and make up a complete human cell. What is more, by no means does a cell consist of a mere heap of proteins. In addition to the proteins, a cell also includes nucleic acids, carbohydrates, lipids, vitamins, and many other chemicals such as electrolytes arranged in a specific proportion, equilibrium, and design in terms of both structure and function. Each of these elements functions as a building block or co-molecule in various organelles.

 

Robert Shapiro, a professor of chemistry at New York University and a DNA expert, calculated the probability of the coincidental formation of the 2000 types of proteins found in a single bacterium (There are 200,000 different types of proteins in a human cell.) The number that was found was 1 over 1040000.244 (This is an incredible number obtained by putting 40,000 zeros after the 1).''

''Let us now examine in detail why the evolutionist scenario regarding the formation of proteins is impossible.

 

Even the correct sequence of the right amino acids is still not enough for the formation of a functional protein molecule. In addition to these requirements, each of the 20 different types of amino acids present in the composition of proteins must be left-handed. There are two different types of amino acids-as of all organic molecules-called "left-handed" and "right-handed." The difference between them is the mirror-symmetry between their three dimensional structures, which is similar to that of a person's right and left hands.

 

The same protein's left- (L) and right- (D) handed isomers. The proteins in living creatures consist only of left-handed amino acids.

 

Amino acids of either of these two types can easily bond with one another. But one astonishing fact that has been revealed by research is that all the proteins in plants and animals on this planet, from the simplest organism to the most complex, are made up of left-handed amino acids. If even a single right-handed amino acid gets attached to the structure of a protein, the protein is rendered useless. In a series of experiments, surprisingly, bacteria that were exposed to right-handed amino acids immediately destroyed them. In some cases, they produced usable left-handed amino acids from the fractured components.

 

Let us for an instant suppose that life came about by chance as evolutionists claim it did. In this case, the right- and left-handed amino acids that were generated by chance should be present in roughly equal proportions in nature. Therefore, all living things should have both right- and left-handed amino acids in their constitution, because chemically it is possible for amino acids of both types to combine with each other. However, as we know, in the real world the proteins existing in all living organisms are made up only of left-handed amino acids.

 

The question of how proteins can pick out only the left-handed ones from among all amino acids, and how not even a single right-handed amino acid gets involved in the life process, is a problem that still baffles evolutionists. Such a specific and conscious selection constitutes one of the greatest impasses facing the theory of evolution.

 

Moreover, this characteristic of proteins makes the problem facing evolutionists with respect to "chance" even worse. In order for a "meaningful" protein to be generated, it is not enough for the amino acids to be present in a particular number and sequence, and to be combined together in the right three-dimensional design. Additionally, all these amino acids have to be left-handed: not even one of them can be right-handed. Yet there is no natural selection mechanism which can identify that a right-handed amino acid has been added to the sequence and recognize that it must therefore be removed from the chain. This situation once more eliminates for good the possibility of coincidence and chance.

 

The Britannica Science Encyclopaedia, which is an outspoken defender of evolution, states that the amino acids of all living organisms on earth, and the building blocks of complex polymers such as proteins, have the same left-handed asymmetry. It adds that this is tantamount to tossing a coin a million times and always getting heads. The same encyclopaedia states that it is impossible to understand why molecules become left-handed or right-handed, and that this choice is fascinatingly related to the origin of life on earth.248''

All quotes come from: Darwinism Refuted.com

[questor]

Pyro, you used to have my respect. Since you are now a moderator, the fight can no longer be even. You have used your position to insult and demean me on numerous occasions with me being unable to answer in kind or defend myself. I don't need that or your snarky comments. You deliberately attempt to provoke me. Why not argue the issue on the thread or buzz off?