EvC Forum: Rodent speciation and Noah's Ark.

Yaro

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Posts: 1797

Joined: 07-12-2003

Message 1 of 31 (274458)
12-31-2005 4:59 PM

Recently, NotSoBlindFaith brought up a few points in the Noah's ark thread that I feel could be better tackled in it's own thread. There are roughly 3000 known rodent species. If the flood happened 3000 years ago, we are expecting a rate of 1 new rodent a year. But, as Discreat_Label pointed out, speciation in a population is non-linear so in truth an actual calculation would be exponential. This means you are expecting on the order of 467 new species a year!

DL's post in it's entirety:

quote:
Well to be truthful a linear equation describing speciation in my opinion would be intelletually dishonest, mostly because populations don't follow linear rates of growth. But understandable to using a linear module because it is the easiest model to describe.
So if we were to assume speciation as an exponential function where
f(x) = 16000(1.001095)^x where x represents time.
Where 1.001095 is extrapolated because 16000 land "kinds" turn into 427,000 land species. We now have an equation that adequately describes the fact that populations are not linear.
However of course there is a flaw in this description because then it demonstrates that the rate of mutation is changing as time is changing. (YECs may believe this is a wonderful thing however, the rate at which speciation is occuring does not match up to observed life)
So again we do a little bit of calculus and we find that the rate of change
f'(x)= 17.5156*(1.001095)^x
which represents the number of speciation events as time changes
plug in 3000 for x into the rate equation and we get a nice round number of:
467 speciation events occuring per year after 3000 years. WOW!!
Course all of this is pure speculation but i think that 427 speciation events occuring like this would indicate a much higher rate of new species discoveries then currently occuring.
Bringing caclulus to new levels of fun.

NSBF responded with the following article:

http://www.theaustralian.news.com.au/...494%255E1702,00.html

This article mentions that new rodent species are discovered at the rate of roughly 1 a year. Presumably NSBF is inferring that those newly discovered species are also newly evolved. NSBF continues by stating:

quote:
No, as you said, we have 3,000 years to get a capybara. Plus you know, beavers and other aquatic rodents have those same features. Also, the order rodentia has less natural variability then what has been isolated by dog breeders. They haven’t had nearly as long to do that. Many species of mouse for instance, look incredibly similar, even though they live at opposite sides of the globe. They only have slight differences, such as the amount of fur on there tails, size, and ear shape. Each of which is quit easy to get in a short amount of time with genetic variation.

There are several problems with NSBF's propositions which I will address here:

1) Newly discovered rodent species are also newly evolved.

Order Rodentia is the larges order of mammals. 3000 species and growing. The fact that we uncover new species every year or so is testament to the groups large size and variability. A similar group of animals in which we discover new species all the time is insects. Insects have over 350,000 known species and the number grows all the time, this does not mean these new species are evolving all the time.

Finally, DL's post made some corrections in the math and notes that we should actually be seeing much more than a rate of 1 species per year. We should litteraly be able to see rodents morphing before our very eyes.

2) Differences between various rodents are not that big and could be bred in the alloted 3000 years.

If NSBF's proposition is true, scientists should be able to breed rats, capybaras, or beavers out of a mouse or perhaps a squirrel. The question is, why can't scientists breed lab mice into capybaras over a succession of years?

Mind you, I don't mean an actual capybara, but rather a capybara like creature?

Scientist's couldn't breed mice into Rats if they tried.

It simply doesn't work in the way NSBF is proposing. As I said in the previous thread a rat and a mouse share a 10% difference in their genome. They are as distant from each other as they are from human beings. NSBF says dogs show more variability. Morphologically, perhaps, genetically NO WAY! The difference between dog breeds is estimated as just below 1%.

Further, NSBF asserts that the differences in capybara and beavers from other rodents, are minor and could be trivially breaded for. This assertion betrays a lack of understanding as to just how different a beaver is from a rat.

The following link notes some of the differences between beavers and other rodents:
Not Found

quote:
Water. The beaver dens near water, feeds in or near water, and usually travels by water. The beaver has several adaptations which make him very much at home in water. His lungs, liver, and heart are so adapted that the animal can stay submerged for up to fifteen minutes and can travel up to one-half mile under water. Therefore, ponds and other bodies of water furnish ready escape from enemies. The beaver's nose and ears are equipped with valves that close when the animal is under water. His lips form a watertight seal that allows the animal to gnaw under water. The beaver's eyes are protected by transparent eyelids which allow good vision under water. His hind feet are completely webbed, which provides good propulsion in water and the leverage to push and pull heavy limbs into place in dams. Beavers in captivity usually require drinking water.

Everything about the animal, from eyes, to it's liver is specialized for living in the water. These things simply could not have arisen from a squirrel-like ancestor some 3000 years ago.

Replies to this message:
	Message 2 by AdminNosy, posted 12-31-2005 5:07 PM	Yaro has replied
	Message 6 by NosyNed, posted 12-31-2005 5:15 PM	Yaro has replied
	Message 10 by Coragyps, posted 12-31-2005 7:08 PM	Yaro has not replied
	Message 12 by Nuggin, posted 12-31-2005 8:16 PM	Yaro has not replied
	Message 19 by pink sasquatch, posted 01-04-2006 4:32 PM	Yaro has replied

Yaro

Member (Idle past 6524 days)

Posts: 1797

Joined: 07-12-2003

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Message 7 of 31 (274471)
12-31-2005 5:20 PM

Reply to: Message 6 by NosyNed
12-31-2005 5:15 PM

Re: New species?

What imediatly comes to my mind is simply why don't we see it happening before our eyes?

Surely we could attempt, thrugh succesive generations, to breed an aquatic rodent from mice in the labs. Yet hundreds of generations of lab mice go by with out any significant diference.

Not only could we attempt it, it should be happeneing anyway. At the rate genetic drift is manifesting itself in rodents, you could expect isolated populations (such as lab mice) to be morphing into all sorts of new kinds of rodents. Yet we don't see that. If we can't do it in the lab, why should we expect that to be happening in the wild?

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	Message 6 by NosyNed, posted 12-31-2005 5:15 PM		NosyNed has not replied

Yaro

Member (Idle past 6524 days)

Posts: 1797

Joined: 07-12-2003

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Message 20 of 31 (275828)
01-04-2006 4:52 PM

Reply to: Message 19 by pink sasquatch
01-04-2006 4:32 PM

Re: a general reply: serious issues with evo arguments

Error 2: Failure to breed beavers from mice refutes rapid speciation:

I have to be picky on this one. I made an unclear statement. I did attempt to clarafy it in the origional post by saying:

quote:
Mind you, I don't mean an actual capybara, but rather a capybara like creature.

Going on the infference that through selective breading you could generate a semi-aquatic mouse etc. Not that an actual beaver as we know it would arise. This was my fault as I was unclear in the initial statement.

This message has been edited by Yaro, 01-04-2006 04:52 PM

This message is a reply to:
	Message 19 by pink sasquatch, posted 01-04-2006 4:32 PM		pink sasquatch has replied

Replies to this message:
	Message 22 by pink sasquatch, posted 01-04-2006 6:23 PM		Yaro has replied

Yaro

Member (Idle past 6524 days)

Posts: 1797

Joined: 07-12-2003

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Message 29 of 31 (276773)
01-07-2006 7:19 PM

Reply to: Message 28 by NosyNed
01-07-2006 1:45 PM

Re: bump NSBF still not really answered

Pink pointed it out. Not crash

I am working on a revision, I have just been very busy the last couple of days. If anyone else want's to put forward a better argument, be my guest.

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	Message 28 by NosyNed, posted 01-07-2006 1:45 PM		NosyNed has not replied

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	Message 30 by RAZD, posted 01-08-2006 6:06 PM		Yaro has not replied

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