Evolution: Religion or Science?

[Southtown]

In the Naturalism model, if it cannot be demonstrated by the scientific method, it does not exist.

The problem with this model is that it is not consistent with the seeking of the unknown that is science...

No, its not like that at all. Just because something isn't currently known does not mean it isn't possible to demonstrate it with the scientific method.

And if something can't, then that's proof it doesn't exist??

[Southtown]

That's not fair to our atheist friends.

MDD isn't talking about atheists being proud, superior, or indignant. When he says athiests play god, he means that they are their own boss and determine their own set of values.

 

This is actually something pretty puzzle for science- but it does not indicate a fundamental problem. Simply because we can't reproduce something in the lab doesn't mean one should posit an entirely new, untestable idea in it's place.

Exactly! Then why replace creation, which was first, with modern unprovable hypotheses?

[Skippy]

I think what you mean by "evolution" is not what it actually is.

Personally, I can agree with that definition of evolution, i.e.- changes within a species. My problem is when someone tries to make the assertion that humans evolved from something, which evolved from something, which evolved from an ape, which evolved from...

 

Where I began to question that theory was when I turned 12 (about 30 years ago) and learned what mammaries were for. I wondered what the reptile mother did to feed its mammalian child and progressed thaty thought to wonder what that child did to find a comparable mate, was there some mass muttation across a region which caused reptilian mothers to hatch mammalian offspring? And mammalian offspring are pretty helpless for months to years and reptiles lay eggs, bury them and go about their lives after that. Just way too many unanswered questions fo rme to agree with macro-evolution.

[Erasmus00]

And if something can't[be demonstrated by the scientific method], then that's proof it doesn't exist??

 

No, but if it can't be demonstrated by the scientific method, it is outside science.

-Will

[Erasmus00]

Then why replace creation, which was first, with modern unprovable hypotheses?

 

First and foremost, evolutionary theories of all kinds make testable predictions. This means that the hypotheses can indeed by demonstrated false. So the unprovable assertion is sort of silly. Second, one very strong reason to replace creation with evolution is that evolution makes predictions, and has explanatory power. Creationism does not have any explanatory power at all.

-Will

[bumab]

MDD isn't talking about atheists being proud, superior, or indignant. When he says athiests play god, he means that they are their own boss and determine their own set of values.

 

Perhaps, but that's a far cry from being God.

 

Exactly! Then why replace creation, which was first, with modern unprovable hypotheses?

 

For one- creationism is also an unproven hyopthesis. Second, evolution is extrodonarily well supported. Third, evolution makes predictions and inspires thought.

 

Finally- I believe the creation story is true. I really don't think it's literally true. Being "a creator" can mean far more then simply doing it with a snap of a fingers. It can also mean sustainer, or creator of purpose. Perhaps God used evolution for His ends. I don't know. Genisis shows whos responsible for creation.

 

Why must you insist on some imagined incompatability?

[Skippy]

Second, evolution is extrodonarily well supported. Third, evolution makes predictions and inspires thought.

Come on people. Evolution is full of holes. It is based on 'could have,' 'might have,' 'may have,' and other such non-definitive phrases. Evoltuionists have no transitional fossils, but they have drawings of those creatures...THAT takes faith!!

 

Scientists (the real ones that actually require evidence) are falling away from evolution every day.

[skuinders]

Come on people. Evolution is full of holes. It is based on 'could have,' 'might have,' 'may have,' and other such non-definitive phrases. Evoltuionists have no transitional fossils, but they have drawings of those creatures...THAT takes faith!!

Scientists (the real ones that actually require evidence) are falling away from evolution every day.

Please pay attention to my posts. Because you are uneducated on the matter, you are not talking about the same 'evolution' as scientists. There are also many transitional fossils. Please read the documents here: http://www.talkorigins.org/faqs/faq-transitional.html

About your last statement, do you have any proof for your claim that scientists are straying away from the theory of evolution? I believe you are wildly wrong there.

[Skippy]

Please pay attention to my posts. Because you are uneducated on the matter, you are not talking about the same 'evolution' as scientists. There are also many transitional fossils. Please read the documents here: http://www.talkorigins.org/faqs/faq-transitional.html

About your last statement, do you have any proof for your claim that scientists are straying away from the theory of evolution? I believe you are wildly wrong there.

I have paid attention. You are talking about a specific part of the evolution discussion. If you doubt that evolutionists believe that all life began from an abiogenetic source, you haven't read far enough yourself. Sure, there may be some evolutionists who have discounted single-cell to reptile to mammal to man just as there are some evangelical Christians who are open to the idea that God's method of creation was to use just such a method to create man and "a day" was just a metaphor for "an epoch." I agree with "Micro" but there is no real evidence for "Macro," it hasn't been duplicated by science (you know, science USUALLY requires that), it hasn't been witnessed (an acceptable substitute to experiment duplication)... it is ALL theoretical supposition.

[Skippy]

Please pay attention to my posts. Because you are uneducated on the matter, you are not talking about the same 'evolution' as scientists. There are also many transitional fossils.

I hit submit too soon....

 

I realize that proponents of creationism as spelled out in Genesis have no experimental evidence to support their beliefs, and there was no human to witness that occurrence - so no need to point that out. BUT THAT IS THE POINT OF THIS THREAD, is it not???? The proponents of the Genesis story for the origin of life would readily agree that they are going on faith (i.e.- religious faith), the question this thread poses is really "Why won't evolutionists agree that their faith in evolution is as much a religious effort as a creationists faith in Genesis?"

[skuinders]

I have paid attention. You are talking about a specific part of the evolution discussion. If you doubt that evolutionists believe that all life began from an abiogenetic source, you haven't read far enough yourself.

It appears that you are talking about talking about a specific application of the theory of evolution... I am not. The term 'evolution' was defined clearly in one of my earlier posts and you are still misinterpreting it. You seem to recognise that this theory can be applied on the micro and macro scales. Now realize that the theory itself is extremely strong - you are questioning one of the applications of the general theory! So please choose your wording more carefully because I don't think you are getting the right message across.

Also, evolution and abiogenesis are not strictly related nor is it required that the people who believe the former believe the latter. This I will not even argue about because it is well known.

 

it hasn't been duplicated by science (you know, science USUALLY requires that), it hasn't been witnessed (an acceptable substitute to experiment duplication)... it is ALL theoretical supposition.

Most of the time in science, it is impossible to observe or duplicate things directly. Science uses inference and extrapolation quite often. We knew the Earth was round for thousands of years, but didn't actually observe it until the 60s.

[Hawkens]

Evolution is just too wide a term anymore. By using the term evolution as your belief over creation then you are applying the full term of evolution (macro) which is nothing more than the athiest method of explaining how life was created without a God. And like it or not....it's a belief not science. There have been no observations of a species change. Nobody has saw a monkey change into a man nor is there any ounce of proof to suggest it.

 

There is somebody offering 250,000 for proof of macro-evolution. Why hasn't anyone collected? That's simple.....because it only exists as a dream.

 

I fully accept micro evolution. It is a proven science.

 

When you use the term evolution to explain how man got on this planet, then you are replacing science with science fiction.

[skuinders]

From Chris Colby:

The Pattern of Macroevolution

 

Evolution is not progress. The popular notion that evolution can be represented as a series of improvements from simple cells, through more complex life forms, to humans (the pinnacle of evolution), can be traced to the concept of the scale of nature. This view is incorrect.

 

All species have descended from a common ancestor. As time went on, different lineages of organisms were modified with descent to adapt to their environments. Thus, evolution is best viewed as a branching tree or bush, with the tips of each branch representing currently living species. No living organisms today are our ancestors. Every living species is as fully modern as we are with its own unique evolutionary history. No extant species are "lower life forms," atavistic stepping stones paving the road to humanity.

 

A related, and common, fallacy about evolution is that humans evolved from some living species of ape. This is not the case -- humans and apes share a common ancestor. Both humans and living apes are fully modern species; the ancestor we evolved from was an ape, but it is now extinct and was not the same as present day apes (or humans for that matter). If it were not for the vanity of human beings, we would be classified as an ape. Our closest relatives are, collectively, the chimpanzee and the pygmy chimp. Our next nearest relative is the gorilla.

 

Evidence for Common Descent and Macroevolution

 

Microevolution can be studied directly. Macroevolution cannot. Macroevolution is studied by examining patterns in biological populations and groups of related organisms and inferring process from pattern. Given the observation of microevolution and the knowledge that the earth is billions of years old -- macroevolution could be postulated. But this extrapolation, in and of itself, does not provide a compelling explanation of the patterns of biological diversity we see today. Evidence for macroevolution, or common ancestry and modification with descent, comes from several other fields of study. These include: comparative biochemical and genetic studies, comparative developmental biology, patterns of biogeography, comparative morphology and anatomy and the fossil record.

 

Closely related species (as determined by morphologists) have similar gene sequences. Overall sequence similarity is not the whole story, however. The pattern of differences we see in closely related genomes is worth examining.

 

All living organisms use DNA as their genetic material, although some viruses use RNA. DNA is composed of strings of nucleotides. There are four different kinds of nucleotides: adenine (A), guanine (G), cytosine © and thymine (T). Genes are sequences of nucleotides that code for proteins. Within a gene, each block of three nucleotides is called a codon. Each codon designates an amino acid (the subunits of proteins).

 

The three letter code is the same for all organisms (with a few exceptions). There are 64 codons, but only 20 amino acids to code for; so, most amino acids are coded for by several codons. In many cases the first two nucleotides in the codon designate the amino acid. The third position can have any of the four nucleotides and not effect how the code is translated.

 

A gene, when in use, is transcribed into RNA -- a nucleic acid similar to DNA. (RNA, like DNA, is made up of nucleotides although t he nucleotide uracil (U) is used in place of thymine (T).) The RNA transcribed from a gene is called messenger RNA. Messenger RNA is then translated via cellular machinery called ribosomes into a string of amino acids -- a protein. Some proteins function as enzymes, catalysts that speed the chemical reactions in cells. Others are structural or involved in regulating development.

 

Gene sequences in closely related species are very similar. Often, the same codon specifies a given amino acid in two related species, even though alternate codons could serve functionally as well. But, some differences do exist in gene sequences. Most often, differences are in third codon positions, where changes in the DNA sequence would not disrupt the sequence of the protein.

 

There are other sites in the genome where nucleotide differences do not effect protein sequences. The genome of eukaryotes is loaded with 'dead genes' called pseudogenes. Pseudogenes are copies of working genes that have been inactivated by mutation. Most pseudogenes do not produce full proteins. They may be transcribed, but not translated. Or, they may be translated, but only a truncated protein is produced. Pseudogenes evolve much faster than their working counterparts. Mutations in them do not get incorporated into proteins, so they have no effect on the fitness of an organism.

 

Introns are sequences of DNA that interrupt a gene, but do not code for anything. The coding portions of a gene are called exons. Introns are spliced out of the messenger RNA prior to translation, so they do not contribute information needed to make the protein. They are sometimes, however, involved in regulation of the gene. Like pseudogenes, introns (in general) evolve faster than coding portions of a gene.

 

Nucleotide positions that can be changed without changing the sequence of a protein are called silent sites. Sites where changes result in an amino acid substitution are called replacement sites. Silent sites are expected to be more polymorphic within a population and show more differences between populations. Although both silent and replacement sites receive the same amount of mutations, natural selection only infrequently allows changes at replacement sites. Silent sites, however, are not as constrained.

 

Kreitman was the first demonstrate that silent sites were more variable than coding sites. Shortly after the methods of DNA sequencing were discovered, he sequenced 11 alleles of the enzyme alcohol dehydrogenase (AdH). Of the 43 polymorphic nucleotide sites he found, only one resulted in a change in the amino acid sequence of the protein.

 

Silent sites may not be entirely selectively neutral. Some DNA sequences are involved with regulation of genes, changes in these sites may be deleterious. Likewise, although several codons code for a single amino acid, an organism may have a preferred codon for each amino acid. This is called codon bias.

 

If two species shared a recent common ancestor one would expect genetic information, even information such as redundant nucleotides and the position of introns or pseudogenes, to be similar. Both species would have inherited this information from their common ancestor.

 

The degree of similarity in nucleotide sequence is a function of divergence time. If two populations had recently separated, few differences would have built up between them. If they separated long ago, each population would have evolved numerous differences from their common ancestor (and each other). The degree of similarity would also be a function of silent versus replacement sites. Li and Graur, in their molecular evolution text, give the rates of evolution for silent vs. replacement rates. The rates were estimated from sequence comparisons of 30 genes from humans and rodents, which diverged about 80 million years ago. Silent sites evolved at an average rate of 4.61 nucleotide substitution per 109 years. Replacement sites evolved much slower at an average rate of 0.85 nucleotide substitutions per 109 years.

 

Groups of related organisms are 'variations on a theme' -- the same set of bones are used to construct all vertebrates. The bones of the human hand grow out of the same tissue as the bones of a bat's wing or a whale's flipper; and, they share many identifying features such as muscle insertion points and ridges. The only difference is that they are scaled differently. Evolutionary biologists say this indicates that all mammals are modified descendants of a common ancestor which had the same set of bones.

 

Closely related organisms share similar developmental pathways. The differences in development are most evident at the end. As organisms evolve, their developmental pathway gets modified. An alteration near the end of a developmental pathway is less likely to be deleterious than changes in early development. Changes early on may have a cascading effect. Thus most evolutionary changes in development are expected to take place at the periphery of development, or in early aspects of development that have no later repercussions. For a change in early development to be propagated, the benefit of the early alteration must outweigh the consequences to later development.

 

Because they have evolved this way, organisms pass through the early stages of development that their ancestors passed through up to the point of divergence. So, an organism's development mimics its ancestors although it doesn't recreate it exactly. Development of the flatfish, Pleuronectes, illustrates this point. Early on, Pleuronectes develops a tail that comes to a point. In the next developmental stage, the top lobe of the tail is larger than the bottom lobe (as in sharks). When development is complete, the upper and lower lobes are equally sized. This developmental pattern mirrors the evolutionary transitions it has undergone.

 

Natural selection can modify any stage of a life cycle, so some differences are seen in early development. Thus, evolution does not always recapitulate ancestral forms -- butterflies did not evolve from ancestral caterpillars, for example. There are differences in the appearance of early vertebrate embryos. Amphibians rapidly form a ball of cells in early development. Birds, reptiles and mammals form a disk. The shape of the early embryo is a result of different yolk concentrations in the eggs. Birds' and reptiles' eggs are heavily yolked. Their eggs develop similarly to amphibians except the yolk has deformed the shape of the embryo. The ball is stretched out and lying atop the yolk. Mammals have no yolk, but still form a disk early. This is because they have descended from reptiles. Mammals lost their yolky eggs, but retained the early pattern of development. In all these vertebrates, the pattern of cell movements is similar despite superficial differences in appearance. In addition, all types quickly converge upon a primitive, fish-like stage within a few days. From there, development diverges.

 

Traces of an organism's ancestry sometimes remain even when an organism's development is complete. These are called vestigial structures. Many snakes have rudimentary pelvic bones retained from their walking ancestors. Vestigial does not mean useless, it means the structure is clearly a vestige of an structure inherited from ancestral organisms. Vestigial structures may acquire new functions. In humans, the appendix now houses some immune system cells.

 

Closely related organisms are usually found in close geographic proximity; this is especially true of organisms with limited dispersal opportunities. The mammalian fauna of Australia is often cited as an example of this; marsupial mammals fill most of the equivalent niches that placentals fill in other ecosystems. If all organisms descended from a common ancestor, species distribution across the planet would be a function of site of origination, potential for dispersal, distribution of suitable habitat, and time since origination. In the case of Australian mammals, their physical separation from sources of placentals means potential niches were filled by a marsupial radiation rather than a placental radiation or invasion.

 

Natural selection can only mold available genetically based variation. In addition, natural selection provides no mechanism for advance planning. If selection can only tinker with the available genetic variation, we should expect to see examples of jury-rigged design in living species. This is indeed the case. In lizards of the genus Cnemodophorus, females reproduce parthenogenetically. Fertility in these lizards is increased when a female mounts another female and simulates copulation. These lizards evolved from sexual lizards whose hormones were aroused by sexual behavior. Now, although the sexual mode of reproduction has been lost, the means of getting aroused (and hence fertile) has been retained.

 

Fossils show hard structures of organisms less and less similar to modern organisms in progressively older rocks. In addition, patterns of biogeography apply to fossils as well as extant organisms. When combined with plate tectonics, fossils provide evidence of distributions and dispersals of ancient species. For example, South America had a very distinct marsupial mammalian fauna until the land bridge formed between North and South America. After that marsupials started disappearing and placentals took their place. This is commonly interpreted as the placentals wiping out the marsupials, but this may be an over simplification.

 

Transitional fossils between groups have been found. One of the most impressive transitional series is the ancient reptile to modern mammal transition. Mammals and reptiles differ in skeletal details, especially in their skulls. Reptilian jaws have four bones. The foremost is called the dentary. In mammals, the dentary bone is the only bone in the lower jaw. The other bones are part of the middle ear. Reptiles have a weak jaw and a mouthful of undifferentiated teeth. Their jaw is closed by three muscles: the external, posterior and internal adductor. Each reptile tooth is single cusped. Mammals have powerful jaws with differentiated teeth. Many of these teeth, such as the molars, are multi-cusped. The temporalis and masseter muscles, derived from the external adductor, close the mammalian jaw. Mammals have a secondary palate, a bony structure separating their nostril passages and throat, so most can swallow and breathe simultaneously. Reptiles lack this.

 

The evolution of these traits can be seen in a series of fossils. Procynosuchus shows an increase in size of the dentary bone and the beginnings of a palate. Thrinaxodon has a reduced number of incisors, a precursor to tooth differentiation. Cynognathus (a doglike carnivore) shows a further increase in size of the dentary bone. The other three bones are located inside the back portion of the jaw. Some teeth are multicusped and the teeth fit together tightly. Diademodon (a plant eater) shows a more advanced degree of occlusion (teeth fitting tightly). Probelesodon has developed a double joint in the jaw. The jaw could hinge off two points with the upper skull. The front hinge was probably the actual hinge while the rear hinge was an alignment guide. The forward movement of a hinge point allowed for the precursor to the modern masseter muscle to anchor further forward in the jaw. This allowed for a more powerful bite. The first true mammal was Morgonucudon, a rodent-like insectivore from the late Triassic. It had all the traits common to modern mammals. These species were not from a single, unbranched lineage. Each is an example from a group of organisms along the main line of mammalian ancestry.

 

The strongest evidence for macroevolution comes from the fact that suites of traits in biological entities fall into a nested pattern. For example, plants can be divided into two broad categories, non- vascular (ex. mosses) and vascular. Vascular plants can be divided into seedless (ex. ferns) and seeded. Vascular seeded plants can be divided into gymnosperms (ex. pines) and flowering plants (angiosperms). Angiosperms can be divided into monocots and dicots. Each of these types of plants have several characters that distinguish them from other plants. Traits are not mixed and matched in groups of organisms. For example, flowers are only seen in plants that carry several other characters that distinguish them as angiosperms. This is the expected pattern of common descent. All the species in a group will share traits they inherited from their common ancestor. But, each subgroup will have evolved unique traits of its own. Similarities bind groups together. Differences show how they are subdivided.

 

The real test of any scientific theory is its ability to generate testable predictions and, of course, have the predictions borne out. Evolution easily meets this criterion. In several of the above examples I stated, closely related organisms share X. If I define closely related as sharing X, this is an empty statement. It does however, provide a prediction. If two organisms share a similar anatomy, one would then predict that their gene sequences would be more similar than a morphologically distinct organism. This has been spectacularly borne out by the recent flood of gene sequences -- the correspondence to trees drawn by morphological data is very high. The discrepancies are never too great and usually confined to cases where the pattern of relationship was debated.

 

Mechanisms of Macroevolution

 

The following deals with mechanisms of evolution above the species level.

 

Speciation -- Increasing Biological Diversity

 

Speciation is the process of a single species becoming two or more species. Many biologists think speciation is key to understanding evolution. Some would argue that certain evolutionary phenomena apply only at speciation and macroevolutionary change cannot occur without speciation. Other biologists think major evolutionary change can occur without speciation. Changes between lineages are only an extension of the changes within each lineage. In general, paleontologists fall into the former category and geneticists in the latter.

 

Modes of Speciation

 

Biologists recognize two types of speciation: allopatric and sympatric speciation. The two differ in geographical distribution of the populations in question. Allopatric speciation is thought to be the most common form of speciation. It occurs when a population is split into two (or more) geographically isolated subdivisions that organisms cannot bridge. Eventually, the two populations' gene pools change independently until they could not interbreed even if they were brought back together. In other words, they have speciated.

 

Sympatric speciation occurs when two subpopulations become reproductively isolated without first becoming geographically isolated. Insects that live on a single host plant provide a model for sympatric speciation. If a group of insects switched host plants they would not breed with other members of their species still living on their former host plant. The two subpopulations could diverge and speciate. Agricultural records show that a strain of the apple maggot fly Rhagolettis pomenella began infesting apples in the 1860's. Formerly it had only infested hawthorn fruit. Feder, Chilcote and Bush have shown that two races of Rhagolettis pomenella have become behaviorally isolated. Allele frequencies at six loci (aconitase 2, malic enzyme, mannose phosphate isomerase, aspartate amino-transferase, NADH-diaphorase-2, and beta-hydroxy acid dehydrogenase) are diverging. Significant amounts of linkage disequilibrium have been found at these loci, indicating that they may all be hitchhiking on some allele under selection. Some biologists call sympatric speciation microallopatric speciation to emphasize that the subpopulations are still physically separate at an ecological level.

 

Biologists know little about the genetic mechanisms of speciation. Some think a series of small changes in each subdivision gradually lead to speciation. The founder effect could set the stage for relatively rapid speciation, a genetic revolution in Ernst Mayr's terms. Alan Templeton hypothesized that a few key genes could change and confer reproductive isolation. He called this a genetic transilience. Lynn Margulis thinks most speciation events are caused by changes in internal symbionts. Populations of organisms are very complicated. It is likely that there are many ways speciation can occur. Thus, all of the above ideas may be correct, each in different circumstances. Darwin's book was titled "The Origin of Species" despite the fact that he did not really address this question; over one hundred and fifty years later, how species originate is still largely a mystery.

 

Observed Speciations

 

Speciation has been observed. In the plant genus Tragopogon, two new species have evolved within the past 50-60 years. They are T. mirus and T. miscellus. The new species were formed when one diploid species fertilized a different diploid species and produced a tetraploid offspring. This tetraploid offspring could not fertilize or be fertilized by either of its two parent species types. It is reproductively isolated, the definition of a species.

 

Extinction -- Decreasing Biological Diversity

 

Ordinary Extinction

 

Extinction is the ultimate fate of all species. The reasons for extinction are numerous. A species can be competitively excluded by a closely related species, the habitat a species lives in can disappear and/or the organisms that the species exploits could come up with an unbeatable defense.

 

Some species enjoy a long tenure on the planet while others are short- lived. Some biologists believe species are programmed to go extinct in a manner analogous to organisms being destined to die. The majority, however, believe that if the environment stays fairly constant, a well adapted species could continue to survive indefinitely.

 

Mass Extinction

 

Mass extinctions shape the overall pattern of macroevolution. If you view evolution as a branching tree, it's best to picture it as one that has been severely pruned a few times in its life. The history of life on this earth includes many episodes of mass extinction in which many groups of organisms were wiped off the face of the planet. Mass extinctions are followed by periods of radiation where new species evolve to fill the empty niches left behind. It is probable that surviving a mass extinction is largely a function of luck. Thus, contingency plays a large role in patterns of macroevolution.

 

The largest mass extinction came at the end of the Permian, about 250 million years ago. This coincides with the formation of Pangaea II, when all the world's continents were brought together by plate tectonics. A worldwide drop in sea level also occurred at this time.

 

The most well-known extinction occurred at the boundary between the Cretaceous and Tertiary Periods. This called the K/T Boundary and is dated at around 65 million years ago. This extinction eradicated the dinosaurs. The K/T event was probably caused by environmental disruption brought on by a large impact of an asteroid with the earth. Following this extinction the mammalian radiation occurred. Mammals coexisted for a long time with the dinosaurs but were confined mostly to nocturnal insectivore niches. With the eradication of the dinosaurs, mammals radiated to fill the vacant niches.

 

Currently, human alteration of the ecosphere is causing a global mass extinction.

 

 

Punctuated Equilibrium

 

The theory of punctuated equilibrium is an inference about the process of macroevolution from the pattern of species documented in the fossil record. In the fossil record, transition from one species to another is usually abrupt in most geographic locales -- no transitional forms are found. In short, it appears that species remain unchanged for long stretches of time and then are quickly replaced by new species. However, if wide ranges are searched, transitional forms that bridge the gap between the two species are sometimes found in small, localized areas. For example, in Jurassic brachiopods of the genus Kutchithyris, K. acutiplicata appears below another species, K. euryptycha. Both species were common and covered a wide geographical area. They differ enough that some have argued they should be in a different genera. In just one small locality an approximately 1.25m sedimentary layer with these fossils is found. In the narrow (10 cm) layer that separates the two species, both species are found along with transitional forms. In other localities there is a sharp transition.

 

Eldredge and Gould proposed that most major morphological change occurs (relatively) quickly in small peripheral population at the time of speciation. New forms will then invade the range of their ancestral species. Thus, at most locations that fossils are found, transition from one species to another will be abrupt. This abrupt change will reflect replacement by migration however, not evolution. In order to find the transitional fossils, the area of speciation must be found.

 

There has been considerable confusion about the theory. Some popular accounts give the impression that abrupt changes in the fossil record are due to blindingly fast evolution; this is not a part of the theory.

 

Punctuated equilibrium has been presented as a hierarchical theory of evolution. Proponents of punctuated equilibrium see speciation as analogous to mutation and the replacement of one species by another as analogous to natural selection. This is called species selection. Speciation adds new species to the species pool just as mutation adds new alleles to the gene pool. Species selection favors one species over another just as natural selection can favor one allele over another. Evolutionary trends within a group would be the result of selection among species, not natural selection acting within species. This is the most controversial part of the theory. Many biologists agree with the pattern of macroevolution these paleontologists posit, but believe species selection is not even theoretically likely to occur.

 

Critics would argue that species selection is not analogous to natural selection and therefore evolution is not hierarchical. Also, the number of species produced over time is far less than the amount of different alleles that enter gene pools over time. So, the amount of adaptive evolution produced by species selection (if it did occur) would have to be orders of magnitude less than adaptive evolution within populations by natural selection.

 

Tests of punctuated equilibrium have been equivocal. It has been known for a long time that rates of evolution vary over time, that is not controversial. However, phylogenetic studies conflict as to whether there is a clear association between speciation and morphological change. In addition, there are major polymorphisms within some species. For example, bluegill sunfish have two male morphs. One is a large, long-lived, mate-protecting male; the other is a smaller, shorter-lived male who sneaks matings from females guarded by large males. The existence of within species polymorphisms demonstrates that speciation is not a requirement for major morphological change.

 

The whole article is here: http://www.talkorigins.org/faqs/faq-intro-to-biology.html

 

I think everyone in this forum should spend more time at talkorigins.org

[Hawkens]

slow down there.....

Given the observation of microevolution and the knowledge that the earth is billions of years old -- macroevolution could be postulated.

Main Entry: 1pos·tu·late

Pronunciation: 'päs-ch&-"lAt

Function: transitive verb

Inflected Form(s): -lat·ed; -lat·ing

Etymology: L postulatus, past participle of postulare; akin to Latin poscere to ask, Old High German forscOn to search, Sanskrit prcchati he asks -- more at PRAY

1 : DEMAND, CLAIM

2 a : to assume or claim as true, existent, or necessary : depend upon or start from the postulate of b : to assume as a postulate or axiom (as in logic or mathematics)

 

I'm willing to go with necessary.

 

Without those billions of years, this theory is nothing. Creationists don't buy into the 4 billion year old Earth. To us, it's at least 6000 to 10,000 years only. So the whole macro-evolution theory holds no water.

 

Maybe we should put the Macroevolution vs Creation debate on hold and get into the actual age of the Earth. :shrug:

[skuinders]

slow down there.....

Main Entry: 1pos·tu·late

Pronunciation: 'päs-ch&-"lAt

Function: transitive verb

Inflected Form(s): -lat·ed; -lat·ing

Etymology: L postulatus, past participle of postulare; akin to Latin poscere to ask, Old High German forscOn to search, Sanskrit prcchati he asks -- more at PRAY

1 : DEMAND, CLAIM

2 a : to assume or claim as true, existent, or necessary : depend upon or start from the postulate of b : to assume as a postulate or axiom (as in logic or mathematics)

Why don't you look at the actual evidence and respond to it? Playing word games does little.

 

Without those billions of years, this theory is nothing. Creationists don't buy into the 4 billion year old Earth. To us, it's at least 6000 to 10,000 years only. So the whole macro-evolution theory holds no water.

Wow, you are way out there. I'm not sure I want to waste my time arguing with you.

EDIT: http://www.talkorigins.org/faqs/faq-age-of-earth.html

[bumab]

Without those billions of years, this theory is nothing. Creationists don't buy into the 4 billion year old Earth. To us, it's at least 6000 to 10,000 years only. So the whole macro-evolution theory holds no water.

 

Maybe we should put the Macroevolution vs Creation debate on hold and get into the actual age of the Earth. :shrug:

 

While I don't agree (i'll just tell ya now), I think you are correct- the age of the earth is a vital pillar of evolutionary thought. If its not that old, then evolution is wrong. So perhaps it would be a better place to start- why should you talk about something when you already disagree with a foundational pillar?

 

There are many age of the earth threads I believe. If you've got some new evidence, or concerns that were not addressed, please start a new thread!

[Hawkens]

Why don't you look at the actual evidence and respond to it? Playing word games does little.]

What evidence?

 

 

Wow, you are way out there. I'm not sure I want to waste my time arguing with you.

EDIT: http://www.talkorigins.org/faqs/faq-age-of-earth.html

This site was created to counter Creationists. Do I need to link you a Creationist site so you can understand where we are coming from? http://www.drdino.com Most "true" Creationists will argue the young Earth. Why is this new news to you?

 

Why can't we find any neutral sites on this? :shrug:

 

Even if I didn't believe in the literal six day creation, the idea that life suddenly happened is absurd. How come this can't be reproduced? There is way too much perfection for life to be explained by chance.