Summations Only

We are more interested in what you can evidence, not what you can see.

Please could you provide evidence that "what you can see" does not constitute evidence?

Taq was replying to Robert Byers' statement that he sees "rapid diversity as an option within Biblical boundaries." Taq's reply to Robert was that he doesn't want to hear his claims about what he thinks he sees, he wants to see his evidence.Robert was claiming that the diversity of species we see today is due to accelerated evolution over a short period after the flood. Do you have any evidence that anything like this ever took place?It would be especially welcome if you could tie your answer in to the topic (Definition of Species), something Robert was never able to do.--Percy

My point was simply about what constitutes evidence. Robert claims that he sees diversity of species today. Eye witness accounts still constitute evidence (especially in court) from what I understand. Furthermore, Robert refers to the bible, an ancient text which must have had an author. This also is valid evidence (even if you disagree with its contents). Robert has therefore supplied his evidence but Taq isn't offering any evidence to counter Robert's claims.

I claim that I see diversity of species today. Eye witness accounts still constitute evidence (especially in court) from what I understand. Furthermore, I refer to "On The Origin Of Species", a text which must have had an author. This also is valid evidence (even if you disagree with its contents). I have therefore supplied evidence to counter Robert's claims.Edited by Huntard, : spellings

Taq said he was interested in what Robert can evidence, not what he can see. By "see" Robert did not mean he had visual evidence, but was just stating his opinion, as when someone begins, "The way I see it..." When Robert says that he sees accelerated evolution as possible within a Biblical context he is offering opinion, not evidence.Robert has enormous difficulty staying on topic, and whether speciation can occur very rapidly does not really have anything to do with the topic. This thread is over four years old, probably time to close it down. If on-topic discussion doesn't resume soon I'll put this thread into summation mode.--Percy

Ok, so Robert has supplied evidence and Huntard has countered with evidence too. This should now make for a lively debate. Enjoy you guys. I will be watching this thread with eager anticipation.

That's not really what people mean by "evidence"...At least, it has to support or counter a claim. Mentioning that a book exists is not supplying evidence.

Robert no longer has posting permissions in this forum. He lost them when he persisted in posting the same unevidenced claims over and over again.Looks like it's up to you.--Percy

Hate to burst your bubble, but neither Robert nor I posted anything coming even remotely close to what would be considered evidence. I had hoped that my silly little attempt at sarcasm would make that clear, but apparently it hasn't. My apologies to you for not telling you in a clear and easy to understand fashion.

I think it's fair to say that we have always disagreed on our interpretations of evidence (other threads demonstrate this). Therefore I am not going to continue to flog the dead horse. You go evidence hunting if you like. I'll sit here and have a cuppa.

This thread is over four years old, I'm throwing it into summation mode.

Anything not related directly to the definition of species is off-topic and should be taken to another thread to pursue, and should NOT be summarized here.It appears that the last time the topic was addressed was ~Message 203, posted 08-06-2010.SUMMARYThe only hard and fast definition point for species is when you have a speciation event and can observe that two or more populations evolved from a single parent population and no longer interbreed. Even so this "point" is spread out over several generations.This definition point does not exist for asexual species or for species evolving in a lineage, when offspring become different enough from ancestors that a point is reached where one might consider them as a new species. This is necessarily rather arbitrary and somewhat subjective, unless a metric can be developed to quantify the amount of differences to use.From Message 1

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I think everyone is fairly familiar with the biological species definition, and some may be familiar with the morphological definition. Here is a site for reference on these definitions:

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U of Michigan Lectures - The Process of Speciation

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Biological species concept: This concept states that "a species is a group of actually or potentially interbreeding individuals who are reproductively isolated from other such groups."

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Morphological species concept: Oak trees look like oak trees, tigers look like tigers. Morphology refers to the form and structure of an organism or any of its parts. The morphological species concept supports the widely held view that "members of a species are individuals that look similar to one another." This school of thought was the basis for Linneaus' original classification, which is still broadly accepted and applicable today.

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Where we can study living populations of sexual species we can use the first definition, but when we deal with the fossil record or with asexual species we would have to use the second definition.

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There is also another definition in the forum glossary:

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http:///WebPages/Glossary.html#S

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A basic taxonomic category for which there are various definitions. Among these are an interbreeding or potentially interbreeding group of populations reproductively isolated from other groups (the biological species concept) and a lineage evolving separately from others with its own unitary evolutionary role and tendencies (Simpson's evolutionary species concept). Employing the terms of population genetics, some definitions can be combined into the concept that a species is a population of individuals bearing distinctive genes and gene frequencies, separated from other species by biological barriers preventing gene exchange.

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These are basic common definitions of species.There are problems with defining exactly what species is in a way that can be applied to all living organisms. The main problem is that all species evolve, so at some point an arbitrary decision is made to call the evolved descendants a different species even though they are members of a continuum.This problem does not exist when speciation events are observed: we have two or more daughter populations that no longer interbreed, where both are descended from a parent population. This branching results in two closely similar pools of genes, and thus we can use the difference between those pools as a metric for comparison to arbitrary species designations:

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Speciation is is the dividing line between what are considered microevolutionary and macroevolutionary processes and mechanisms, between the generation of homogeneous change within a population (evolution), and the generation of heterogeneous change (diversification) between diverging (especially for new) species.

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Thus I would define any population with a single peak frequency distribution as a species, any population with two peaks and a high "saddle" between them as incipient species, and any population with two peaks and a low "saddle" as different species. Analysis of this type of pattern for species like horses, zebras and donkeys would give you an idea of the saddle height necessary for speciation.

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Measuring the frequency distribution of hereditary traits within populations, and comparing them to later generations with different frequency distributions to determine when the amount of difference compares to speciation event differences would take some of the arbitrariness out of linear species assignments.Another possibility is to run a cladistics analysis to determine when the branching is more than seen within species between varieties.Enjoy.Edited by RAZD, : added

What all of these definitions are trying to get at is the underlying genetic mechanisms, those of inheritance and divergence. Even for asexual species you are still talking about a population that is constantly competing leading to cycles of founders and flushes as rare beneficial mutations appear in the population. With sexual species we try to adjust our definitions to reflect gene flow.When we say that two living populations are separate species what we are trying to relate is the idea that both species were once one species. Through whatever means, that ancestral population split and the two halves began building up differences as mutations accumulated through time.For fossil species we have are looking at the process in action. We can not directly look at the genotype, but we can look downstream of the genotype which is the phenotype. We can see how each branch started accumulating different mutations (or different selective pressures) as evidenced by a difference in morphology.At the foundation of the species definition is inheritance, and the mechanisms of genetics. The results of these simple mechanisms can be quite complex which makes a one-size-fits-all definition of species nearly impossible.