Quick question on evolution

[PsychoSarah]

I'm not sure I'd say that vertebrate fish will always produce vertebrate fish, though I can see where that would come from.

The problem is that with very slow change, each generation is always the same species as the last. Species is defined by the fact that they can interbreed, and in general two generations are close enough that they can. But over time as changes accumulate, the first one in the series (if it were still alive, which of course it won't be) would no longer be able to breed with the most recent.

Thus eventually you can get a new species. You can even go from invertebrate to vertebrate. But you only see that when you look over time. If you just look at one generation, the change are small enough that you'd call them the same species and the same kind (by which I mean vertebrate, etc.)

Of course things are complicated by interbreeding and by space. E.g. if all members of the species interbreed with each other enough, changes will spread throughout the group, and it's possible that everyone will continue to be the same species (even though it may change enough that a biologist would give it a new name). But if they don't (e.g. if some end up in Australia), they won't interbreed, and the populations will develop independently.

I'm by no means sure that human descendants will always be homo sapiens. We developed from different species, and over time we might change enough that we could no longer interbreed with those today. If we settle other planets, and there isn't much space travel, we could even split into multiple species. That's if we live long enough, which I'm not sure is very likely.

Give this man a round of applause, for he gets it

 

[Seipai]

Ok, so a vertebrate fish will give birth to another vertebrate fish, and they'll always produce vertebrate fish. I suppose that non-vertebrate fish will always produce non-vertebrate fish. Yet, a non-vertebrate fish is supposed to have a common ancestor with a vertebrate fish? That's the part I don't understand.

Technically you are a vertebrate fish too.

It seems you have no understanding of evolution at all.

How can you criticize an idea that you don't understand?

 

[PsychoSarah]

Technically you are a vertebrate fish too.

It seems you have no understanding of evolution at all.

How can you criticize an idea that you don't understand?

Mostly, by being vague.

 

[Strathos]

A very short, but precise answer:

God's intervention. In other words, it takes many miracles to get it done.

Are you saying that God isn't competent enough to create a system that works without His constant supervision and intervention?

 

[lesliedellow]

I don't know if I would use aging as a comparison to evolution, because aging happens on an individual scale and evolution happens on the population scale across generations.

I needed an analogy which involved gradual change, and I explicitly said that, when applied to Evolution, entire species were involved; not just individuals.

 

[biggles53]

I asked my question, not wanting to debate, but rather to try to understand. So please take this in the spirit intended. It seems to me that someone growing up is not a reasonable analogy to evolution. The person neither gains nor loses DNA in the growing process; there is no reproduction involved; and not only does the person remain a "person" they actually remain *the same* person. Hopefully there's a better explanation (that I can still understand). Thanks.

Ok, so a better analogy is the gradation between you and your parents and between you and your offspring....

Even though your parents are humans and so are you and so will your offspring be, there are minor differences in your individual genetic make ups. You possess a number of mutations in your genome that your parents don't have...likewise, your kids will possess mutations that neither you nor your parents have.

Over VERY long periods of time and many, many generations, these mutations may accumulate to a sufficient degree for us to recognise clear differences between the ancient population and the current one.

And we don't have to look back into antiquity to see the results of this process....Google up the wall lizards of Croatia and you'll find out about the effect of 'ring species'....

 

[juvenissun]

Are you saying that God isn't competent enough to create a system that works without His constant supervision and intervention?

I don't say it. TE people DO!

 

[PsychoSarah]

I don't say it. TE people DO!

No they don't, in fact, theistic evolutionists often view evolution as a process god set up and left to do its thing. Which is why evolution as a theory doesn't conflict with the idea that deities exist.

 

[juvenissun]

1 word: caterpillars

In terms of intelligence, I don't see a difference.

 

[juvenissun]

No they don't, in fact, theistic evolutionists often view evolution as a process god set up and left to do its thing. Which is why evolution as a theory doesn't conflict with the idea that deities exist.

Yes they do.

I am not one of them. So find one and you will learn some.

 

[PsychoSarah]

In terms of intelligence, I don't see a difference.

You said that aging creatures are essentially the same when they age as they were when they were young, I gave an example to disprove that statement, because anyone with functioning eyes can see that a butterfly is very different from the caterpillar it started out as. Nothing about intelligence was brought up in the conversation, so intelligence wouldn't be a factor in my answer.

 

[juvenissun]

You said that aging creatures are essentially the same when they age as they were when they were young, I gave an example to disprove that statement, because anyone with functioning eyes can see that a butterfly is very different from the caterpillar it started out as. Nothing about intelligence was brought up in the conversation, so intelligence wouldn't be a factor in my answer.

It is.

 

[PsychoSarah]

It is.

It might be now, so what exactly do you want or are questioning, that intelligence of life can change over time?

 

[[serious]]

Ok, so a vertebrate fish will give birth to another vertebrate fish, and they'll always produce vertebrate fish. I suppose that non-vertebrate fish will always produce non-vertebrate fish. Yet, a non-vertebrate fish is supposed to have a common ancestor with a vertebrate fish? That's the part I don't understand.

When we talk about monophyletic groupings (common ancestor groups), which are the only things to which "X always produces X" applies, we must be cautious not to try and apply it to non monophyletic groups. Vertebrates are a distinct group, but invertebrates isn't. An ant and a jellyfish are both not vertebrates, but that doesn't imply any grouping between ants and jellyfish.

Another common one that people pop up with and try to discuss as if it's a monophyletic group is fish. Fish can't be treated that way either.

 

[hedrick]

I don't say it. TE people DO!

I identify myself with theistic evolution simply because the alternative normally assumes atheism. But I don't believe TE is any different in the way things work.

The Reformed tradition assumes that God almost always acts through "secondary causes." That is, he has a plan for everything that happens, but that plan involves normal natural processes and human choices. God doesn't have to intervene all the time. God's personal interaction normally involves people, where it takes the form of the Holy Spirit working with his followers.

The problem with God intervening all the time is that it would result in a chaotic universe, where people's choices didn't matter, because God would determine the results independent of normal processes. Christians believe in creation, not pantheism. That is, God created a universe that has an existence of its own, operating lawfully. For most of Christian history, this lawfulness was taken to be a reflection of God's own character.

 

[PsychoSarah]

I identify myself with theistic evolution simply because the alternative normally assumes atheism. But I don't believe TE is any different in the way things work.

The Reformed tradition assumes that God almost always acts through "secondary causes." That is, he has a plan for everything that happens, but that plan involves normal natural processes and human choices. God doesn't have to intervene all the time. God's personal interaction normally involves people, where it takes the form of the Holy Spirit working with his followers.

The problem with God intervening all the time is that it would result in a chaotic universe, where people's choices didn't matter, because God would determine the results independent of normal processes. Christians believe in creation, not pantheism. That is, God created a universe that has an existence of its own, operating lawfully. For most of Christian history, this lawfulness was taken to be a reflection of God's own character.

Except human choices still wouldn't matter if this god is all powerful and all knowing, because it would already know the results of all those choices before they were even made.

 

[[serious]]

I put this together for a previous thread:

A eukaryote might develop a true multicellular colony organism, but it's still a eukaryote.
A multicellular organism might develop bilateral symmetry, but it's a multicellular eukaryote.
A bilaterally symmetrical multicellular eukaryote might develop a hollow nerve cord (vertebrate) but it's still a A bilaterally symmetrical multicellular eukaryote
a vertebrate bilaterally symmetrical multicellular eukaryote might develop a calcified internal skeleton, but it's still, well, you get the picture.
Go through that same thing with:
a jaw
4 limbs
lungs
amniotic eggs
hair
opposable thumbs
bipedal locomotion
etc.

 

[dysert]

Allow me a detailed answer on this one, as it is indeed a good question.
Before we start, let met address your statement in bold. Instead of trying to find out what "evolutionists" "believe", why don't you simply learn some evolutionary biology? Perhaps it is what you meant, but evolution theory is a theory of biology. You don't have to rely on what people believe to learn about it.

Having said that, let's start.

The central key of evolution is inheritable genetics/traits and mutation.
Let's leave sexual reproduction out of this for a second as it makes the tree of life more complex and it would only distract you from the mechanism I'm about to explain (although it applies just as well for breeding pairs, off course). So let's assume for simplicity that newborns have only 1 parent.

(warning: hypothetical numbers ahead, for the sake of example)
In that case, a newborn is an exact copy of his parents + some changes.
You are, indeed, 99.999% the same as your parent. That 0.001 % difference is unique to you. That represents your mutations. All newborns have mutations. This is called the mutation rate. In human species, I think that number is about 175 mutations per newborn. The vast majority of which is actually pretty much neutral in effect.

When you get a child, then the same thing happens. The child is 99.999% the same as you, with 0.001% difference due to its own mutations. It also inherited YOUR mutations. So it is 99.999% the same as you and 99.998% the same as your parent. And so it continues down.
Your kid will have a kid, he will have a kid, he will have a kid, etc.

All of them will be 99.999% the same as their direct parent.
After a long time, still being 99.999% the same as its direct parent, it will be perhaps only 97% the same as YOU.

What is the result? Well... that every single newborn is always of the same species as its direct parents. And it gradually, very gradually, changes through the generations. At some point, you would look back thousands of generations ago and find out that BIG changes have taken place. At the core, that descendent far into the future will still have YOUR DNA, which was inherited through the ages. But it will have become a new species.

So all off spring of Homo Sapiens will forever belong to the group of Homo Sapiens. Homo Sapiens will not turn into canines. Canines are on another branch of this family tree. Homo Sapiens will no doubt speciate further into subspecies. But they are forever "stuck" in the Homo genus. That's their ancestry. That's the DNA they've inherited through the ages. And it ain't going anywhere.

You've surely heared that Humans evolved from primates. This is correct. What is also correct is that humans are STILL primates. That will never change. We are also still mammals. And tetrapods. And vertebrates.
We share an ancestor with all primates. We share an older ancestor with all mammals. We share an older ancestor with all tetrapods. Etc.



Too difficult to comprehend? Let's try an easy analogy. I love this: languages.

As you probably (or hopefully) know: Italian, French and Spanish are called "Roman languages". They are called that because they all derived from Latin.

At one point, the ancestors of Italian, French and Spanish speaking people all spoke Latin. Let's called Latin the ancestral species.

Now, how did we get from Latin to those 3 other languages?
Consider this: at no point in history did a latin speaking mother give birth to a spanish speaking child. Instead, each child was always brought up in the SAME language as its parents. But generation after generation, the latin changed. Some words were altered, accents were altered, dialects formed, fonetics changed. All in gradual manner. Again, at no point did a generation speak a different language then the previous generation.

Yet, here we are: French, Italian and Spanish. All different languages with the same roots. All three are still Roman languages. Just like humans are still primates.


Feel free to ask additional questions if you feel like you need to.
I'll be more then happy to do my best to answer them (or point you to what might be able to answer them) if you are sincere in your request.

Thanks for the good explanation, but I admit I'm still having trouble. (Although I was quite accomplished in getting my college degrees, I was never very good at biology.) I'd like to keep things as simple as possible.

Maybe I'm misunderstanding what you said, but it seems to me that you're saying that an offspring is the same type of being as its parent, but with a tiny change at its core. If you go on for millions (?) of generations these tiny changes will have resulted in an offspring eventually being a totally different type of being as the ancient ancestor. Is that right?

If I understand you right, then I guess you're saying that there once was a bacterium many millions (?) of generations ago, and because of the tiny changes, that bacterium's offspring eventually resulted in a human?

 

[dysert]

Technically you are a vertebrate fish too.

It seems you have no understanding of evolution at all.

How can you criticize an idea that you don't understand?

I have gained some understanding that I didn't have before. And I haven't criticized anything. Where'd you get that from?

 

[PsychoSarah]

I have gained some understanding that I didn't have before. And I haven't criticized anything. Where'd you get that from?

He jumped the gun, he should appologise.