Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
5 online now:
Newest Member: popoi
Post Volume: Total: 915,815 Year: 3,072/9,624 Month: 917/1,588 Week: 100/223 Day: 11/17 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   explaining common ancestry
macaroniandcheese 
Suspended Member (Idle past 3927 days)
Posts: 4258
Joined: 05-24-2004


Message 1 of 159 (268207)
12-12-2005 1:56 PM


since it seems that there is some misunderstanding as to how common ancestors are defined and how they "share traits of their progeny" and so forth, perhaps we should have some clarifying discussion.
bio i spose.
This message has been edited by brennakimi, 12-12-2005 01:56 PM
From Carico in Message 85:
It doesn't explain how the "common ancestor" got the traits of a human, or where it came from, the incalculable mutations that would have had to have occur by chance in the myriad of generations of apes, what this "common ancestor" looked like, or if it even existed at all! If you're going to say that this "common ancestor" just appeared, then why not simply believe that God created humans? What other explanation for our miraculous life can there be except from a miraculous source?
now, i'm sure carico isn't the only one with this misunderstanding. so, one: where do common ancestors come from? two: how did they "get" human traits. three: any other thoughts?
i'd like to see comments from evo people as well as more questions from creos. but can we please keep it an honest question and answer session and not a "but god said 111!!!oneonewtfbbq". if you want to understand evolution's position more, great. if you just want to berate our heresy, save your fingers.
This message has been edited by brennakimi, 12-12-2005 02:18 PM
This message has been edited by Admin, 12-12-2005 02:59 PM

Replies to this message:
 Message 2 by Admin, posted 12-12-2005 2:01 PM macaroniandcheese has replied
 Message 8 by Wounded King, posted 12-12-2005 4:55 PM macaroniandcheese has not replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 2 of 159 (268211)
12-12-2005 2:01 PM
Reply to: Message 1 by macaroniandcheese
12-12-2005 1:56 PM


If this is to provide a thread to explore Carico's questions from the Why is evolutions primary mechanism mutation ? thread, if you elaborate a bit I can release this. You could cut-n-paste one or two of Carico's questions in and then respond to them.

--Percy
EvC Forum Director

This message is a reply to:
 Message 1 by macaroniandcheese, posted 12-12-2005 1:56 PM macaroniandcheese has replied

Replies to this message:
 Message 3 by macaroniandcheese, posted 12-12-2005 2:18 PM Admin has not replied

  
macaroniandcheese 
Suspended Member (Idle past 3927 days)
Posts: 4258
Joined: 05-24-2004


Message 3 of 159 (268224)
12-12-2005 2:18 PM
Reply to: Message 2 by Admin
12-12-2005 2:01 PM


better?

This message is a reply to:
 Message 2 by Admin, posted 12-12-2005 2:01 PM Admin has not replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 4 of 159 (268257)
12-12-2005 3:00 PM


Thread moved here from the Proposed New Topics forum.

  
Carico
Inactive Member


Message 5 of 159 (268263)
12-12-2005 3:08 PM


Thank you. Someone is finally attempting to answer my questions. I've been told by some evolutionists that the common ancestor didn't have any human traits and by others that they did. So hopefully, I'll get some consistent answers. Thanks again.

Replies to this message:
 Message 6 by macaroniandcheese, posted 12-12-2005 3:20 PM Carico has replied

  
macaroniandcheese 
Suspended Member (Idle past 3927 days)
Posts: 4258
Joined: 05-24-2004


Message 6 of 159 (268273)
12-12-2005 3:20 PM
Reply to: Message 5 by Carico
12-12-2005 3:08 PM


it's nice to get people who are willing to honestly recieve information. hopefully someone will jump on this for you. any info i could give would be elementary at best. it's been a few years since i was a bio major and i'm sure much has changed since then.

This message is a reply to:
 Message 5 by Carico, posted 12-12-2005 3:08 PM Carico has replied

Replies to this message:
 Message 7 by Carico, posted 12-12-2005 3:24 PM macaroniandcheese has not replied

  
Carico
Inactive Member


Message 7 of 159 (268278)
12-12-2005 3:24 PM
Reply to: Message 6 by macaroniandcheese
12-12-2005 3:20 PM


Thank you.

This message is a reply to:
 Message 6 by macaroniandcheese, posted 12-12-2005 3:20 PM macaroniandcheese has not replied

Replies to this message:
 Message 9 by nwr, posted 12-12-2005 5:14 PM Carico has replied

  
Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 8 of 159 (268319)
12-12-2005 4:55 PM
Reply to: Message 1 by macaroniandcheese
12-12-2005 1:56 PM


1)How the "common ancestor" got the traits of a human?
The answer is simple, it didn't, or at least it is very unlikely that the latest common ancestor of chimps and humans had any particularly unique and characteristic human traits. The point of a common ancestor is not to be a 'missing link', i.e. supposedly half human and half chimp, but rather to be an animal which has all of the features which are common to both humans and chimps, and ideally for the best resolve features common to those two groups alone.
So the 'Common ancestor' would not have uniquely human traits, they would be hypothesised to have arisen in the intervening generations as the 'common ancestral' species diverged into 2 distinct human and chimp lineages as seen from this point in time.
2) As to how these traits arose during the evolution of the human lineage; The answer has to be the obvious one of mutation and natural selection. Most of the traits which distinguish us from chimps are highly complex polygenic traits the gconstituent genetic components of which are phenomenally hard to unravel.
The are some suggestive studies on things such as speech where the gene Foxp2 has been shown to affect the neurological deveopment of systems involved in speech and language (Vargha-Khadem , et al., 2005). Many of the differences we consider most important are likely to be cognitive, the merely morphological differences may be a lot easier to pin down in the long run.
TTFN,
WK

This message is a reply to:
 Message 1 by macaroniandcheese, posted 12-12-2005 1:56 PM macaroniandcheese has not replied

Replies to this message:
 Message 12 by Carico, posted 12-12-2005 8:26 PM Wounded King has not replied
 Message 25 by RAZD, posted 12-12-2005 10:43 PM Wounded King has not replied

  
nwr
Member
Posts: 6408
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.1


Message 9 of 159 (268332)
12-12-2005 5:14 PM
Reply to: Message 7 by Carico
12-12-2005 3:24 PM


On scientific theories
Hello Carico, welcome back.
Since nobody else has posted much to this thread, let me start. And I want to start by explaining what is a theory.
Let me start by talking about the theory of gravity. I'm sure you have heard of it. One of the things that the theory of gravity allows us to explain, is how the earth moves around the sun in an elliptical orbit. Apologies if this looks like a diversion. But I would rather start with a theory that you probably accept. Then I'll comment on the theory of evolution later in this message.

On the theory of gravity


Strictly speaking, the theory of gravity does not tell us anything about the sun or about the earth. The theory is about process that exist in nature. Those processes would exist even if there happened to be no sun and no earth.
When we measure some facts about the sun and the earth, we can use the theory of gravity to compute how the earth should move around the sun. A good way of describing this is that the theory of gravity allows us to interpret data (measurements) and use them to make useful predictions.
Scientists are often sloppy when they talk about theories. They often say "the theory of gravity tells us how the earth moves around the sun". However, strictly speaking, the theory doesn't say anything about this. It should be "the theory of gravity, together with some measurements of the earth and sun, tell us how the earth moves around the sun".
I hope you can see how it is often convenient for scientists to be a bit sloppy in what they say. Unfortunately, that sloppiness can be confusing to non-scientists trying to understand what they say.

On the theory of evolution


The theory of evolution is about processes, and how they are involved in changes in biological creatures. Believe it or not, but the theory of evolution does not say that apes evolved into humans. That's because it is about processes. The theory itself would be just as valid even if there were no apes and no humans.
We use the theory of evolution to help us interpret data and make predictions. In this case the data is what we know about species that exist today and what we know from fossils. The theory of evolution can thus tell us how anxient species could evolve into modern species.
Most scientists believe that humans evolved from apes. People will sometimes say "the theory of evolution says that apes evolved into humans." But, strictly speaking, the theory itself does not say that, since it is only about the processes. A better statement would be "the theory of evolution, together with the known data, implies that humans evolved from an earlier species of apes."
Strictly speaking, even that last statement is not quite right. The problem with it, is that we have too few fossils to fully map out the origin of humans. The evidence that humans evolved from apes is very strong, and no evolutionist doubts it. But it actually does fall a little short of proof. There are currently at least two (probably more) hypotheses on the evolution of humans. According to one hypothesis (the Aquatic Ape Theory), humans evolved from a species of aquatic apes that lived near the shore and probably used fish as the main diet. The other hypothesis is that a band of apes adapted themselves to living on the savannah instead if in the forest, and humans evolved from these savannah apes.
I think the majority of evolutionists think the aquatic ape hypothesis is very unlikely, and the way we evolved is more likely to be along the lines of the savannah hypothesis. I mention both of these hypotheses only to indicate that the exact path by which humans evolved is uncertain.
The main conclusion is that there is still some uncertainty on the history of human origins. However, we do know that modern humans have been on earth for far longer than the 6000 year age that some creationists claim. There are fossils of modern humans, and there are human artifacts which are significantly older than that.
Enough for now. Unless somebody beats me to it, I will later post something about the processes of evolution, and about how it might have happened.

This message is a reply to:
 Message 7 by Carico, posted 12-12-2005 3:24 PM Carico has replied

Replies to this message:
 Message 16 by Carico, posted 12-12-2005 8:55 PM nwr has replied
 Message 24 by RAZD, posted 12-12-2005 10:29 PM nwr has not replied

  
robinrohan
Inactive Member


Message 10 of 159 (268341)
12-12-2005 5:27 PM


we are related to all life
One can also point out that not only are we related to apes but to other creatures as well. I and my cat are distant relations. About a hundred million years ago there was a little creature in the forest which we call a Eutherian. This little fellow is the ancestor of both me and my cat. We are much more closely related to the ape than the cat, but in fact we are probably related to every life form. It's a big family tree. So your cousin would correspond by analogy to an ape (I have several cousins that I would characterize that way) and a very distant 10th cousin would correspond to the cat.

  
Coragyps
Member (Idle past 734 days)
Posts: 5553
From: Snyder, Texas, USA
Joined: 11-12-2002


Message 11 of 159 (268362)
12-12-2005 6:08 PM


what this "common ancestor" looked like, or if it even existed at all! If you're going to say that this "common ancestor" just appeared, then why not simply believe that God created humans?
The most recent common ancestor of humans and chimps likely looked a little like either - tailless, hairy, probably walking sometimes on two feet and sometimes knuckle-walking. Likely they were decent tree-climbers. They almost certainly had small brains - ape-sized ones. They had to eat fruit to get vitamin C, because a gene required to make it was inactivated in their species. They could get gout, because a gene required to oxidize uric acid was inactivated in their species.
They most certainly didn't "just appear." They had ancestors, too, just like you and I do. As you dig up older and older fossils, these ancestors get smaller and less ape-looking. They would be described by a zoo-goer of today as more like a monkey or a lemur, perhaps. Go back to fifty million years ago and you'd say "squirelly-looking". 340 million years and you'd swear it was a toothy salamander. All these critters bred with critters that looked almost like them - at least as much as I look like my wife. All of them had kids that looked almost like them - as much as my kids look like me. But they weren't identical. Five hundred generations down from some ancestor in the line that led to you and me, you might have occasionally found a later ancestor that looked enough different to make you say, "Hmmm. That may not be quite the same critter as that last one I examined! The zygomatic process isn't quite the same...."
The reasons I don't "simply believe that God created humans" are that the rocks and fossils and DNA don't lie. There are bucketfuls of evidence for our common ancestry with not just chimps, but with all life on earth. There's not a thimbleful of evidence for any god.

Replies to this message:
 Message 14 by Carico, posted 12-12-2005 8:36 PM Coragyps has not replied

  
Carico
Inactive Member


Message 12 of 159 (268413)
12-12-2005 8:26 PM
Reply to: Message 8 by Wounded King
12-12-2005 4:55 PM


So if this common ancestor didn't have human traits, then why is it called a common ancestor?
This message has been edited by Carico, 12-12-2005 08:27 PM

This message is a reply to:
 Message 8 by Wounded King, posted 12-12-2005 4:55 PM Wounded King has not replied

Replies to this message:
 Message 13 by robinrohan, posted 12-12-2005 8:30 PM Carico has not replied
 Message 15 by Belfry, posted 12-12-2005 8:39 PM Carico has not replied

  
robinrohan
Inactive Member


Message 13 of 159 (268415)
12-12-2005 8:30 PM
Reply to: Message 12 by Carico
12-12-2005 8:26 PM


So if this common ancestor didn't have human traits, then why is called a common ancestor?
Because he's the great,great, great, great, etc., etc grandfather of what became human beings millions of years down the road.

This message is a reply to:
 Message 12 by Carico, posted 12-12-2005 8:26 PM Carico has not replied

  
Carico
Inactive Member


Message 14 of 159 (268419)
12-12-2005 8:36 PM
Reply to: Message 11 by Coragyps
12-12-2005 6:08 PM


So when you say; "probably", then this is all in the imagination, is it not? And if this ancestor all had ancestors, then how did the first one just appear? There always has to be a beginning, my friend.
Fossils don't lie, but people do. On the show "Ape to Man" on the History channel, a scientist found a piece of what looked like bone and from that, drew a sketch of a complete being covered with hair. Then after he put it through carbon dating, he couldn't prove it was even a bone fragment! So this kind of fossil determination is again from the imagination.
Also, carbon dating is no longer thought to be reliable because any fossil found on the ground that was exposed to any kind of heat, alters the ability to date it. So previous dating is now no longer thought to be reliable. So again, humans can perceive a fossil to be anything they want and exclude the myriad of other variables involved in identifying it.
And just recently, scientists have said that the DNA in humans shows that all humans are descendants of one man. But again, they neglect to look in Iraq where the bible says that man was first formed because they might prove the bible true. So they look in Africa and then declare that those were the earliest bones instead of saying those are the earliest bones they have found. So it is this kind of tunnel vision that provides the information that scientists give to the world, then leap to conclusions that exclude all other variables.
This message has been edited by Carico, 12-12-2005 08:39 PM

This message is a reply to:
 Message 11 by Coragyps, posted 12-12-2005 6:08 PM Coragyps has not replied

Replies to this message:
 Message 17 by NosyNed, posted 12-12-2005 9:09 PM Carico has not replied

  
Belfry
Member (Idle past 5085 days)
Posts: 177
From: Ocala, FL
Joined: 11-05-2005


Message 15 of 159 (268420)
12-12-2005 8:39 PM
Reply to: Message 12 by Carico
12-12-2005 8:26 PM


Carico writes:
So if this common ancestor didn't have human traits, then why is it called a common ancestor?
No, WK said that it wouldn't have any uniquely human traits - it would have many traits in common with humans and many in common with apes, just as humans and modern apes share many traits in common. But the differences that we consider uniquely human would, almost by definition, be lacking in an ancestor species that we and modern apes have in common.

This message is a reply to:
 Message 12 by Carico, posted 12-12-2005 8:26 PM Carico has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024