I've been puzzling over how to better answer this question.
it's an infuriating question because once you understand the answer it's obvious and simple but it's a perennial - it just won't go away. The reason it won't is because evolution is not understood by most people and ignorant religionists repeat this supposedly slam dunk question over and over.
I read on a thread on this site what I thought was a really good start to an answer that can be understood by anyone - I just wanted to flesh it out and develop the full picture.
Edit - this is the latest version, May 2012.
“If we descended from apes, how come apes are still here?”
What’s wrong with this picture?
Well nothing or pretty much everything – depending on what you think it shows.
If you see it as man evolving over millions of years from ape-like ancestors, you’re right. But if you see it as a picture of how modern monkeys change into people, that’s probably why you may ask the question:
“If we descended from apes, how come apes are still here?”
To ask that question means that there’s a vital piece of information missing from the questioner’s understanding of what evolution is. That vital piece of information is the concept of the tree of life, that all things are related to each other.
An evolution scientist on hearing that question might ask you a question back. Such as:
"if I'm descended from my grandfather, how come he still exists?"
“If dogs are descended from wolves, how come there are still wolves?”
Here’s fuller explanation.
Chimpanzees are apes and one of our closest animal relatives - their scientific name is Pan troglodytes.
Now, imagine that you are standing face to face with a female chimpanzee - let’s call her Pan. With your left hand you are holding the hand of your mother and your mother is holding the right hand of her mother and so on for thousands of generations back into the past. By doing this, you know as an absolute certainty that you are descended directly on your mother’s side to everyone in the chain.
Imagine that Pan is doing the same but with her right hand.
You now have two imaginary lines of women and female chimps holding hands going backwards in time - like a railway track with women and chimps lining each side.
You can now walk down the centre of the rails and look carefully at your mother's family line and the chimp's family line going back millions of years.
So what would do you see?
Walking back about 200,000 years on the human side you see a mother who’s husband was a chap science named Heidelberg Man (Homo heidelbergensis ) she’s distinctly human, using tools and standing upright, probably hairless and very tall – the males are up to 7 feet tall. This is the first different species that we’ve come across in our chain. But you wouldn’t be able to tell exactly when Homo sapiens (people) merged into Heidelberg because each mother would look almost identical to the next – you can’t see the join. The changes from mother to mother are so gradual that you only see a change by comparing mothers thousands or millions of years apart. We only now know that Heidelberg is different from us because we’ve found his fossilised remains and we can compare it to ourselves today.
This is why there’s no such thing as a transitional fossil or a missing link; every fossil is a transitional fossil and every living species is in transition to the next – if we had a fossil for every mother in the lines, even the experts wouldn’t be able to say where a separate species had been formed. We can only guess with hindsight.
If you find this hard to grasp or you think it’s impossible for one species to change slowly into another we can see it happening today. For example, we call species that change slowly over geographic areas rather than over time, ring species.
Here in the UK the Herring Gull and the Lesser Black-backed Gull are distinct and non-interbreeding species. But if you physically follow the Herring Gull west towards North America it gradually blurs into something more like a Lesser Black-backed Gull. It carries on changing towards Siberia and when it finally returns to Western Europe the Herring Gull has become a Lesser Black-backed Gull and the two species don’t interbreed. At no point in the ring can you say exactly where it changed species – it’s a gradual merging of characteristics over distance.
As you walk back further, at about 500,000 years ago, you’d see a branch form and go off sideways from our human line, these are the Neanderthals (Homo neanderthalensis). They lived along side us but developed separately. There may even be Neanderthal mothers in our line, because we think that for some time there was interbreeding.
And so on down the line of mothers through increasingly apelike creatures until at about 2.5 million years ago we reach an animal called the Southern African ape (Australopithecus africanis). This creature is small – around 4 feet, with a brain a third the size of ours and although she stands upright like us, she’s covered in hair and is distinctly apelike. We used to think that this is roughly where chimps split from the human line but modern molecular genetics tells us that it was earlier.
We have to walk much farther down the lines to get to where most evolution scientists think chimps branch off - somewhere about 7m years ago. This mother would have looked something like a chap called ‘Taumai’ (Sahelanthropus tchadensis). He has the same brain size as a modern chimp but his face is a little more like a human than a chimp.
No one knows for sure whether Taumai is the point where chimps start off on their own line but we do know one thing for certain:
Wherever the split actually happened, at this point in the two lines of human and chimp descendants you would see that the right hand of a mother from the chimp line is now holding the left hand of a mother from the human line. The lines have met – the ancient chimp and the ancient human have the same mother.
This mother starts the lines to both Pan and you, so Pan is your distant cousin. And both you, the human, and Pan, the ape are still here.
So the apes developed along one line and we humans along another. We were in competition with each other whilst in the forest but the reason that there wasnt only one final surviving winner is because our ancestors moved from the trees onto the open savannah grasslands whilst the apes stayed in the forest.
Once in the open we HAD to adapt to survive in the new environment; walking upright in order to run quickly and for long durations, losing hair to keep cool, developing tool use in order to hunt. The apes in the forest were already adapted to their environment so they developed along their own arboreal paths.
Both the 'why do I still have cousins?' and 'why are there still Scandinavians?' questions help generally as opening comments, but they really only impress those of us that already get it.
I'm trying to pull together a more complete explanation so that someone for whom the idea is both new and difficult can understand. There are plenty of people that are entirely puzzled by it but are prepared to try.
One obvious thing you'd see straight away as you walked down the human line would be the height and age of the mothers - they would get progressively shorter and younger wouldn't they?
On the chimp line, nothing much would change except over millennium.
Anyone know off-hand where the parallel lines meet - pan prior? - what it would look like and where it would live? (Meanwhile, Google is my friend..)
What we can surmise about Pan Prior:
It lived in African forests more than 6 million years ago. When the Ice Age made forests shrink about 7 million years ago, Pan Prior was split into two subgroups. The subgroup that spread to the grasslands became man. It may have been tool-using, as both species to evolve from it are. (On the other hand, Chimp tool use might be geologically recent, say the past 4,300 years or so) It was probably rather smaller than modern humans. It was generally a very adaptable species, willing to switch up it's behavior to survive in new environments.
The idea that humans were all shorter, then 20th century nutrition suddenly shot them up in height is dubious. An analysis of the 43 people buried at a mass grave near the Battle of Towton (1461, for those whose British history isn't so hot) showed that their height varied from 1.5 to 1.8 metres tall. This puts them in the range of average height for English men today, and leaves the average a bit taller than men in 18th century England. These things vary.
Hmm - that's interesting and a little disappointing :-)
Could it be that those involved in the battle were warriors and therefore larger? I really don't want to believe that all those medieval buildings had doorways too small for the people living in them!
Is there any evidence that modern man gets taller with improved nutrition? Are Asians in fast developing countries like India and China getting taller?
The flip responses given by Dr. Adequate, PaulK, and others in this thread ought to be sufficient to see that the question misses the mark. Someone who cannot see that the question is facially ridiculous given those answers is never going to understand a more detailed answer. Don't waste your time.
Ah, but you've grown cynical and case hardened; I'm new here and haven't had to give the same answer a thousand times yet ;-)
I've also seen the genuine puzzlement and and also interest when they're presented with the argument for the first time. Some of them have never heard the other side of this at all or even given it a thought before.
And, bless 'em, a lot aren't very bright or used to thinking about ideas and concepts. They deserve a proper answer.
- We don't know much about the details of what we would see down the chimp line. They were forest-dwellers, and things don't fossilize as well in forests as they do in the savannahs where the human line largely lived.
Yeh, that's disappointing. It leaves my argument a little naked. Then I hit the imaginary Pan prior and I have to explain a bloody 'missing link'.
The two final offspring holding the hands of the same mother where the two parallel lines cross is, of course, the punchline. But I'm missing the actual mother....
quote:You are making a bad assumption at the start - that any amount of "answering" will overcome the Creationist mindset.
This, unfortunately, is not true.
Sheesh, you guys are Vietnmam vets that have been in the jungle too long, 'the only good gook is a dead gook'. Too much time arguing against the odds with properly deluded fundies I suppose.
Not all people who ask this question are dyed-in-the-wool, no hope, fanatics; those that come to sites like this to argue the toss are extremists of both kinds - I'm the atheist kind - but the vast majority aren't and some are interested in the answers because they haven't heard them before.
As it happens, it looks like I've picked the wrong story; science doesn't yet have the chimp line story sorted out at all. No intermediates between chimp and the common ancestor and no bloody common ancestor to hold hands with. Pity.
It seems to me you are arguing against evolution here. Are you not?
I am not a creationist and that's the last time I'm going to say it.
However, if I was a creationist, I would have a half decent point wouldn't I?
We - and to be clear, I include myself - say that H sapiens is an ape and that our closest relative is Pan troglodyte, also an ape. It would have been nice to show the lines of descent to our joint common ancestor, Pan prior, using fossil evidence but it seems I can't. And worse, we only have Pan prior as an idea, not a fossil.
The fact that we find few fossils in arboreal environments where the chimp line lived is a bloody nuisance for my proposed explanation - it would sound like an excuse to those on the other side of the argument so I can't easily use it.
Well in order to demonstrate that the existence of humans, the existence of other apes, and the theory of evolution are mutually consistent, it isn't necessary to have a complete set of intermediate forms, just to show that there's no inconsistency --- that the evolution of humans wouldn't somehow magically make all the other apes disappear.
Completely agree - just in this particular case if fcuks up my story. (Which would have been a good one had it worked).
Well in fact now I think about it displaying a complete set of intermediates wouldn't actually answer the "why" question any more than pointing out that chimpanzees etc are not actually extinct. Anyone who thought that that would be contrary to theory could go on thinking it.
It would simply demonstrate, with evidence, how both lines developed from a common ancestor and it would have been quite a powerful story that is fairly easily explained.
I wasn't expecting it to change all creationist's minds - particularly the ones found on these boards.
I seem to remember that the horse has a pretty good fossil record - anyone know what its nearest living relative and common ancestor are? ["Hello Google"]
So maybe a way to answer the question is to explain all the above about humans and chimps, then say that because all the descendants of horses AND their nearest living relative shared the same environment (?) and because that environment was the open plains where fossils survive (?) we have a good fossil record of both lines going back to best a guess common ancestor.
"if horses descended from Xs, why are Xs are still here?"
I'm not looking for a complete record and know that it doesn't and can't exist and I know the reasons why.
We've also tried showing that the question is fundamentally flawed but it still keeps being asked despite that.
So, I'm just looking for some good fossils in the lineage of an iconic species that fits the purpose of my story. It doesn't need to be complete, it just needs to show a logical progression to back up the concept. It's a basic teaching method - illustrate your ideas with examples that support the story in a rational way.
Then why not go with the most iconic species of all: us.
That was/is the plan - we have several good fossil steps down the Homo line towards Pan p. what I'm missing are any equivalent steps on Pan t's line, plus no Pan p fossil.
I am hoping to do better with a horse and rhino - or some such.
But it occurred to me that we have an extant example of how two species can evolve from a common source yet both be still around today - ring species.
Here in the UK the herring gull and the lesser black-backed gull are distinct and non-inerbreeding species. But if you follow the herring gull west towards Siberia and North America it gradually blurs into something more like a lesser bb gull. When you finally return to Europe there are two distinct species.
It's not a great example as the creationist wants the bird to change into a bat or a cactus, not another similar seabird; but it does change and they can see it for themselves.
Actually, cats and dogs look like good candidates - Carnivoramorpha with what looks like good fossil record for both lines. Even a creationist knows what a cat and a dog is and that they're different 'kinds'.