Evolution Lesson

[John Hyperspace]

One of the interesting benefits of fossils being rare is that they normally depict species that are thousands of years apart or more, so the morphological differences even between "closely" related species in the fossil record can be easily seen through side-by-side comparison.

I presume "closely related species" means "two fossils that look similar"? But what I'm asking is how we know(or, posit) that one species has become a different species? That's basically what it's all about, true? How do we determine "this one became that one": based on what criteria?

So much so, that teeth or a part of a skull is usually enough to at least get to the genus level, if there are other fossils of that species already found. When you have very few pieces to start with, they can be kept in categorical limbo until enough are found to make a classification.

And a "genus" is defined as, what? Same definition as "species" or?

Psychology.

Makes perfect sense.

 

[John Hyperspace]

How do we determine when someone has changed from being young to being old? Is there an exact microsecond in their life when they stop being young and become old, and is this change objective and easily identifiable?

Easy, you define precise criteria for "young" and "old": if I define "young" as "ages 5-10" and old as "ages 11-20" then youth becomes old at the 11th birthday. This is the benefit of defining terms.

 

[Speedwell]

Easy, you define precise criteria for "young" and "old": if I define "young" as "ages 5-10" and old as "ages 11-20" then youth becomes old at the 11th birthday. This is the benefit of defining terms.

The point is, the terms are entirely arbitrary. The example of age is a good one: in some situations, a person is considered an adult when he is 18; in others, 21.

 

[John Hyperspace]

The point is, the terms are entirely arbitrary.

Okay, but is something being scientifically proposed? If a field of science is talking about old and young, and haven't defined the terms properly, then they can't make any propositions based on the terms since they're undefined. This is the point. If a field of science says "the person has gone from young to old" and I ask "by what definition?" and the reply is "there is no definition" then their proposition has no inherent meaning.

In other words, are you proposing something about "young" and "old" to me? If so I am asking for your definitions of "young" and "old"; by what criteria is your proposition?

 

[Speedwell]

Okay, but is something being scientifically proposed? If a field of science is talking about old and young, and haven't defined the terms properly, then they can't make any propositions based on the terms since they're undefined. This is the point. If a field of science says "the person has gone from young to old" and I ask "by what definition?" and the reply is "there is no definition" then their proposition has no inherent meaning.

In other words, are you proposing something about "young" and "old" to me? If so I am asking for your definitions of "young" and "old"; by what criteria is your proposition?

Talking about species, of course there is a definition; or rather, there are several, depending on what kind of evidence is available--morphology, fossil, DNA, etc. and to what use the species determination is to be put.
I don't really see why this is an issue, unless you have some special reason to regard exact determination of speciation as important.

 

[Loudmouth]

Okay, but is something being scientifically proposed? If a field of science is talking about old and young, and haven't defined the terms properly, then they can't make any propositions based on the terms since they're undefined.

Are you saying that people don't age because you can't produce an objective hard line between old and young?

That's pretty much the argument you are making against evolution. If evolution is true, then there will be an arbitrary line between species. The reason we can't point to a hard, objective definition for species is because of evolution. It is exactly what we would expect to see if evolution is true.

If anything, the difficulty in defining species is a much more serious problem for creationists who claim that species were created separately.

This is the point. If a field of science says "the person has gone from young to old" and I ask "by what definition?" and the reply is "there is no definition" then their proposition has no inherent meaning.

We do have definitions for each species group. That's what we keep telling you.

 

[Loudmouth]

Easy, you define precise criteria for "young" and "old": if I define "young" as "ages 5-10" and old as "ages 11-20" then youth becomes old at the 11th birthday. This is the benefit of defining terms.

Those are entirely arbitrary definitions, are they not?

 

[John Hyperspace]

Talking about species, of course there is a definition; or rather, there are several, depending on what kind of evidence is available--morphology, fossil, DNA, etc. and to what use the species determination is to be put.
I don't really see why this is an issue, unless you have some special reason to regard exact determination of speciation as important.

Well, it's an issue when you propose "this species became that species" in order to produce evidence of your proposition. I'm now having to ask, by what definition, and, by what criteria, are you making the proposition.

 

[Loudmouth]

Well, it's an issue when you propose "this species became that species" in order to produce evidence of your proposition.

Is the arbitrary nature of defining old and young a problem for the claim that people age? If I claim that an old person grew from a young person but I can't definitively show the microsecond when they went from young to old using objective criteria, does it mean that I have not proven my claim?

 

[John Hyperspace]

Those are entirely arbitrary definitions, are they not?

If you want to make propositions about young and old, define away. But if you're going to make scientific propositions then I'm going to need you to define your terms so I can actually understand what it is you're saying, especially when you're positing evidence for a propositional support.

I've got nothing at all against the concept of evolution (which, still hasn't been defined in this thread: I'm having to presume it's being used according to popular definition?) but so far all I'm getting from the question is some very vague responses. I'm seeking to know, how we can tell when one past "species" has "evolved" into another "species".

 

[John Hyperspace]

Is the arbitrary nature of defining old and young a problem for the claim that people age? If I claim that an old person grew from a young person but I can't definitively show the microsecond when they went from young to old using objective criteria, does it mean that I have not proven my claim?

No, I wouldn't doubt your claim. You're stating a fact that I experience in the present. It's self-evident.

 

[Loudmouth]

If you want to make propositions about young and old, define away. But if you're going to make scientific propositions then I'm going to need you to define your terms so I can actually understand what it is you're saying, especially when you're positing evidence for a propositional support.

That's exactly what scientists do with species. I have even described those definitions for you. Am I missing something here?

I've got nothing at all against the concept of evolution (which, still hasn't been defined in this thread: I'm having to presume it's being used according to popular definition?)

Perhaps you missed post 37 where I defined it:

"It [evolution] is most often defined as a change in allele frequencies within a population over time. It is also defined as descent with modification."

I'm seeking to know, how we can tell when one past "species" has "evolved" into another "species".

You define the two species using morphological features and show how fossils separated by larger time periods fit into the two species.

 

[Loudmouth]

No, I wouldn't doubt your claim. You're stating a fact that I experience in the present. It's self-evident.

But how do you know when someone goes from being young to being old?

 

[Speedwell]

I'm seeking to know, how we can tell when one past "species" has "evolved" into another "species".

When it has become different enough from its parent species, by one of the criteria already explained, to make it useful to biologists to classify it separately.

 

[Loudmouth]

If the second law of thermal dynamics is that everything tends to disorder, how does that square with evolutions theory that something greater was created out of something lesser, that evolution created order and progress from chaos and disorder?

You started life as a single cell and developed into a complex human over a 9 month period. If that doesn't violate the 2nd law, then the same process over billions of years does not violate the same law.

What you are missing is that it is the sum of the system that goes towards disorder. This still allows for local regions to increase in order, as long as the sum of the whole goes towards disorder.

 

[Loudmouth]

How did new biochemical pathways, which involve multiple enzymes working together in sequence, originate?

Each new protein improved the system, so it was kept.

Charles Darwin admitted that the available fossil evidence didn’t support his theory of evolution.

Citation?

But he expected that plenty of evidence would be found in the coming years. Now, more than a century and a half later, the evidence still fails to support his theory. Where are the, expected, countless millions of transitional fossils?

We don't expect to have millions of transitional fossils because fossilization is rare and we have only searched a tiny fraction of the fossil record.

 

[John Hyperspace]

When it has become different enough from its parent species, by one of the criteria already explained, to make it useful to biologists to classify it separately.

 

[John Hyperspace]

But how do you know when someone goes from being young to being old?

I'm not the one making scientific propositions here so why are you asking me? Are you making a scientific proposition or positing evidence of some propositional conclusion concerning "young" and "old"? If so, define your terms. If not, what is the relevance? I am asking how you determine when one "thing that looks similar/i.e. species" has changed into another "thing that looks similar/i.e. species" since both will obviously "look similar" and be of the same "thing that looks similar/i.e. species" to begin with.

How can you determine when one past "thing that looks similar" has transformed into a different "thing that looks similar" without having criteria to define "difference in similarity" and enough criteria to justify something as "evidence" of such a process?

 

[Loudmouth]

We have already explained that fossil species are defined by morphological differences. Each species group is going to have different criteria, so I really don't know what more you want out of us. Did you want to discuss specific fossil species? Perhaps we could compare Homo erectus and Homo sapiens?

H. erectus (Turkana boy on the right)

Anatomically modern H. sapiens

Look at the sloping forehead, forward jutting jaw, large eyebrow ridges, and smaller cranium for H. erectus. Now look at H. sapiens. We see a tall forehead, lack of large eyebrow ridges, a jaw that doesn't jut forward, and a strong chin process. This is how we define these two species, and how the differences between them allow us to assign them to different species. No modern human has the feature set seen in H. erectus.

 

[Loudmouth]

I'm not the one making scientific propositions here so why are you asking me?

Do you know what the Socratic method is? (there's a joke in there)

I am trying to help you understand the scientific proposition, and why evolution produces a gradual continuum of morphology that requires an arbitrary line between species.

If so, define your terms.

We already did. Fossil species are defined by their morphology, as explained numerous times now.

How can you determine when one past "thing that looks similar" has transformed into a different "thing that looks similar" without having criteria to define "difference in similarity" and enough criteria to justify something as "evidence" of such a process?

From post 60:

"Usually through statistical tests such as means, standard deviations, and multivariate analyses. They use physical measurements of bones and muscle placements in order to have concrete numbers to work with."