Question About Evolution

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I was discussing evolution with someone who buys into young earth creationism, and they asked me the usual "well if we came from Chimpanzees, why are there still Chimpanzees". I explained that we didn't come from Chimps, but rather a common ancestor we share with Bonobos and Chimpanzees that lived 6 million years ago. I also explained that physiologically, it probably would have resembled a chimp more than a human, but this is because the Chimp never left the trees, the original environment of the shared progenitor, so there were less physiologically apparent adaptations needed than the human ancestral line that split off and filled a new niche in the retreating forests that were being displaced by grasslands through climate change.

However, they hit me with a hard question I couldn't answer, and that's "why in recorded history hasn't a new species developed". They defined a species as a boundary in which a group of organisms can interbreed. The question was, more or less "why hasn't any group of organisms gone from a state of being able to interbreed within a wider circle of closely related organisms to a more restrictive circle?"I mentioned mules, but that doesn't really apply since they can't reproduce at all. I imagine that in the event that a new species does form, it probably would happen through the kind of intercourse that a donkey and horse (close enough to produce offspring but different enough to produce a freak or oddity) provide, but I don't know of any real world examples. If someone could fill me in on this, let me know.

They argued that a kind of meta-consciousness brought all the different life forms into being through intention and that, while different species can change form to a limited extent (Saber tooth tigers to Siberian Tigers/ Woolly Mammoths to Elephants), there is no organic based, common line of descension that all life shares, only commonality shared through a meta-physical intelligence.

That's an easy one. Recorded history is very recent. We really don't have any documents past what, 3000 years ago? Evolution doesn't typically happen overnight, it takes tens of thousands of years to occur. So you aren't going to see new species popping up every day. That said, there have been new species develop in our lifetime. Mostly it's just microorganisms like bacteria (they reproduce so fast that you can notice evolution much easier with them), but also with some other animals. And while species typically refers to two organisms that can't physically reproduce that isn't always the case (see: lions and tigers). Here's a link describing a few new species:

http://www.abc.net.au/science/articles/ ... 820949.htm

Also a little basis on how evolution occurs is helpful. Typically what causes large changes in a species is a set of genetic mutations that turn out to be beneficial to survival or reproduction, and therefore those mutations get passed down to descendants. For an easy example think of the antibiotic resistant bacteria that are all over the news nowadays. There are some species of bacteria that naturally have antibiotic resistance, or develop a mutation that confers this resistance, and some that don't. In a world without antibiotics, neither one is favored and therefore you don't see any changes in the relative amounts of either over time, the gene is a non-issue. However when you start using antibiotics, you kill off all the bacteria that don't possess the gene, and the only ones left are those that are resistant. Then in turn, those bacteria produce more antibiotic resistant ones until that's all that's left! And also as you can see these two types of bacteria can coexist, just because one has evolved to have more resistance doesn't mean that the bacteria that don't have the resistance just "die off".

Also for the record, I am a Christian and I do have pretty strong spiritual beliefs. But I personally don't see the Bible as antagonistic with respect to evolution. Rather, I see it as a supporting argument for evolution. But that's just how I feel and a topic for another day .

Last edited by Stargazer43 on 01 Nov 2012, 1:54 pm, edited 1 time in total.

Let me provide some more high calibre depleted uranium SLAP ammunition. Can't be too careful with those darn young earth creationists .

http://en.wikipedia.org/wiki/Apple_maggot
http://en.wikipedia.org/wiki/Divergent_evolution
http://en.wikipedia.org/wiki/Adaptive_radiation



http://en.wikipedia.org/wiki/Last_universal_ancestor

The probability estimates of a common ancestor versus multiple ancestors are quite informative (I wanted to post a link to the Nature article, but I no longer have a subscription to scientific journals ).



Demonstrated by this awesome study.
http://en.wikipedia.org/wiki/E._coli_lo ... experiment

And the author even put Conservapedia (an "intellectual" bastion of Young Earth Creationism, BTW) in its place. Good read... and Good Fun!
http://www.conservapedia.com/Conservape ... ski_dialog

There you go. Ready for round two.

Be aware, though, that all Young Earth Creationists have a fact resistance of 20 + Class Level + Fallacy modifier (They get it for free! Seriously IMBA!), so I hope you took Tireless Rebutter as a starting Feat at level 1 and avoided multiple attribute dependency.

Eppur si muove.

First time I understood evolution 5-6 years ago when I found some forgotten potatoes which have had worms. At that moment, I thought the worms evolved from bacteria inside the potatoes, which most probably were maggots, but that actually helped me to understand the theory of evolution that made no sense to me before in spite of all the proofs and documentaries. Even now I wonder how some people can understand things without making associations.

To reiterate what was said above- your creationist friends have no concept of time scales.

Writing was invented only 5 thousand years ago- in the ancient near east. The American West was "prehistoric"(ie had no literate people to write records) until a couple hundred years ago.

Compare that to the 100's of thousands of years it takes for species to split from one another.

Its like asking "why havent any new mountains (besides volcanoes) formed in recorded history". Like species, folded mountains take so long to form that its impossible to precieve them as forming on a human timescale while its happening.

GGP provides great info for your use. I'll add :

The concept of what defines a species is still being debated. The breeding/interbreeding argument has many holes and cannot really be used to define what constitutes a species.

For example, we know for a fact that modern humans are the result of millions of years of evolution... and that our ancestors not only shared the world with other hominid 'species' but also interbred with them. The most recent evidence is modern homo sapien interbreeding with neanderthal and with a much older species, the denisovans. The denisovans evolved nearly 800 thousand years ago and the neanderthals about 500 to 600 thousand. Early homo sapien variants interbred with neanderthal in europe/coastal north africa and middle east whereas the homo sapien group that pushed into asia met and mixed genes with the Denisovans.

So.. in two separate examples our own 'species' bred with 'species' that were hundred of thousands of years older. As long as the genetic compatibility is there it will happen..albeit rather rarely.

For a 'species' to become unable to breed with a once closely related variant species it needs to drift genetically either by extensive adaptations or by genetic isolation in which the inbreeding they go through speeds up genetic incompatibility.

So you end up with a very long period of time in which different 'species' can still breed but perhaps the viable offspring are extremely rare. Horses and Donkeys could very well be on their last leg of splitting into genetically incompatible species...and mules being sterile shows it. It would take the horse or the donkey to undergo more adaptive mutations or genetic isolation from each other for it to happen though.

Its a morbid thought but in my anthro class it was discussed that modern humans could probably produce viable offpsring with an ancestor as distant as homo erectus. Thats a ~2 million year old ancestor. The DNA is almost identical. We cant breed with chimps and their DNA is a single digit % difference..Erectus is a fraction of that.

Evolution occurs over much longer periods than the few hundred years modern science has been around.

I would argue though, we can view evolution on a small scale in bacteria and how they become resistant to anti-biotics.

The problem there is that most bacteria mostly reproduce asexually, and conjugation happens between very different species anyway. So the YEer could argue that this doesn't meet her definition.

Her definition is irrelevant as compared to the scientific definition, and I believe bacteria *do* meet said definition.

Her definition is relevant because she is the one who has to be convinced. The fact is, those bacteria are not a group of organisms that has gone from a state of being able to interbreed within a wider circle of closely related organisms to a more restrictive circle.

The problem isn't that evolution doesn't occur, the problem is that the YEer has heard some dodgy arguments against evolution and those are affecting her world view. Speciesation (or whatever the word is) occuring in asexual organisms doesn't undermine her argument, so shouldn't be used as a rebuttal.

It's a common question that YEC's ask and one that has been answered over and over again. Speciation of sexually reproducing organisms *has* occured since recorded history. Here are the four best known examples, but there are many others.

http://www.talkorigins.org/faqs/speciation.html

How come evolution never considers the superhuman?

A bit of elaboration might be necessary here. What is a superhuman?

Could a woman be a superhuman?

I'm guessing he's referring to Nietzsche and the Ueberman, a highly successful human who has such a great effect on the world that their impact is widely felt even after their bodily death, someone who will stop at nothing to further their goals.

That could barely be considered evolution though, there are billions of people who have been more "successful" in propagation terms than, say, John Lennon (two children, no grandchildren yet), or Hitler (no surviving descendants) but who have died without leaving a mark on more than their immediate circle of friends.

Most creationists are too stupid and ignorant when it comes to earths history and the origins of life because they are too afraid of picking up a science book and learn the truth.Their response would be oh snap the bible is incorrect about the planets history! They don realize that the earth is by far older than some 4000 year old book written by a bunch of desert bums!

Last edited by AspieOtaku on 01 Nov 2012, 5:53 pm, edited 1 time in total.