Biblical "kinds"


#21

From the YEC view, we’re talking about less than 2000 years from Adam to Abraham and we already have donkeys. Do you still think this is plausible?


(Chris) #22

From the YEC view it’s about 350 years from the flood to Abraham. Say 10 generations for a horse/donkey. That’s not much but
(a) it depends on the genetics of the original pair in the kind. Even the first generation could have produced offspring with marked variation. As Darwin has noted in regard to pigeon breeding even a few generations can produce marked differences in the hand of a skilled breeder.
(b) the difference between horse and donkey need not have been as marked as it is today for them to have been differentiated as separate varieties by Abraham’s time.
(c ) even today the horse and donkey are close enough to breed and occasionally produce fertile offspring. They might have been closer in Abraham’s time.

So it is possible that even by purely natural means donkeys could have been around in Abraham’s time. However
(d) Theistic evolution does not preclude guidance or intervention by God in the differentiation process, and neither does YEC.


(Haywood Clark) #23

How could it account for the polymorphism we observe just within one of those species today?

The original pair could have no more than 2 alleles per locus. Where did all of the other alleles for polymorphic loci come from?

Your description of the YEC view does not fit the reality we observe today.


(Chris) #24

4 alleles per locus (except for X/Y chromosomes).

Hey, I just doubled the genetic diversity available.


(George Brooks) #25

@aarceng

So speciation in evolution cant lead to dramatically different animals in millions of years…

But speciation can create zebras in 10 generations?


(Chris) #26

Remember that at 10 generations they (horses, donkeys, zebras) were probably not as differentiated or as reproductively isolated as they are today; noting that they can still occasionally produce fertile offspring so even today it is incipient speciation using the biological species concept. All that was required by Abraham’s day was that they should be recognised varieties. This is the approximate equivalent to producing a new dog breed.

To create a new dog breed , a dog breeder must establish a set of clearly measurable and visible traits known as the breed standard. It is a list of characteristics that formally describe the breed to an audience. The breeder needs to build up the new dog breed over several generations , generally taking decades. Breeding Business, 2016-2017

So yes, 10 generations would be sufficient.

Could it be repeated today? Maybe not. Each of the equine varieties (horses, donkeys, zebras) have a subset of the original genetic diversity. There is less to work with so it’s more difficult to create new varieties. Each new variety or species would have less genetic diversity and be less able to adapt to changing environments, increasing the risk of extinction. Speciation is a step toward Extinction.


(Chris) #27

I’m not familiar with Sigrid Hartwig-Scherer however the implication of the quote would seem to be that the Australopithicines are a different Kind to Homo.


(Chris) #28

btw. Did nobody notice my huge calculation error! :flushed:


(Matthew Pevarnik) #29

I don’t think its a matter of less to work with, but a matter of how fast each generation can differ from the previous one. In other words, you need an exquisitely high number of substitutions per site and then a decrease to the present rate. Even if you could have ‘lots of raw genetic material’ inside of an organism and could somehow make lots of combinations of such material there would be no reason why you should ever get the zebra stripes for example unless there was a population of such animals and they were subject to selective pressure. Otherwise every single unique combination would be completely lost in the generation afterwards with so much changing. There would not be any convergence on anything in particular without massive numbers of offspring with all similar genetics. But again this could never happen because each one is apparently changing so incredibly fast you would never get any two offspring even remotely similar.

The fastest change we’ve ever measured today is this one which is less than 3,000 generations:

No it’s not. The number of species has been increasing:

If your prediction or idea is correct, then we should have seen a massive slope in the early fossil record and then a decrease ever since then. Even if you want to condense the fossil record into 4-6 thousand years, the pattern we see doesn’t match what you are telling us.


(Chris) #30

10 generations in 350 years would be 35 years per generation. Horses can breed from as young as 2 years (according to the internet) so allowing 3.5 years gives 100 generations.

What an embarrassing blunder.


(Mervin Bitikofer) #31

Sorry - the math police here must be short-staffed at the moment. Your humiliation is duly noted. :policeman:


(Chris) #32

Note that I am comparing the horse/donkey/zebra group to dog breeds. Dog breeds can be produced quite quickly by breeding out undesired characteristics. That does not require any substitutions per site. The horse/donkey/zebra ancestor probably did have stripes although probably not as marked as the zebra today. The legs of Przewalski’s horse are often faintly striped. Stripes have been lost in our modern horse but accentuated in the zebra. Since we don’t have to wait for random mutations this can happen quite rapidly.

In this case we aren’t talking about speciation in the sense of complete reproductive isolation. Even today horse/donkey/zebra can interbreed and the progeny is sometimes fertile so they haven’t reached that stage. At the time of Abraham they wouldn’t have been as separate as they are today; it would have been enough for them to be identifiable as distinct varieties. hence your example of marine fish is irrelevant.

But you misunderstood; that’s not an answer to my claim. Say a population splits into two species (or varieties). Each of those species will have a subset of the original gene pool so each will, separately, have less genetic diversity even though the total genetic diversity could be maintained. If each of those species splits again then each of the 4 species will have less genetic diversity than for the 4 combined. There is an increase in the number of species but each species has reduced genetic diversity. Each species then is less able to adapt so is more vulnerable to extinction if environments change.

In the case of dogs we’re only talking about varieties but even so, as a 2008 BBC documentary, “Pedigree Dogs Exposed” shows, there is a genetic cost of breeding purebred dogs. The bigger dog breeds become susceptible to hip dysplasia, others are plagued by heart problems. The King Charles Spaniel is prone to an extremely nasty condition, syringomyelia (SM), in which the skull is too small to house the brain. Bulldogs have slower relative growth of the nasal bones, and this causes breathing difficulties and they need to be born by Caesarian section. Dogs with floppy ears are prone to ear infections.


(Randy) #33

@aarceng, that’s a great suggestion–but isn’t there a critical mass at which that becomes less of a problem? Dog breeds are extremely inbred (like making an Adam and Eve over and over again, with incest, from my understanding), whereas the mechanism for speciation isn’t just isolation, founder effect, and environmental pressure when you have a larger population. Saudi Arabia has a tendency to intermarry in close family groups and tends to have lots of genetic diseases (they run a registry to avoid cousins marrying now), but apparently Iceland doesn’t have that problem and may even have some advantages to marrying 3rd cousins! @pevaquark and others can comment better on that.

but Brother Chris, my purpose here is not to convince anyone of evolution. As a Christian, it’s to relate to both nonChristians and Christians faithfully while trying to truthfully understand both the Bible and science. It’s a fun discussion, but I’m not an expert and find that I learn a lot from talking to you and others as well. Thanks for iron sharpening iron.


(Chris) #34

Inbreeding / incest is not a particular problem if there are no genetic defects, unless the population becomes homozygous for one or multiple alleles (loss of genetic diversity). The original created Kinds including Adam and Eve would have been genetically perfect. By the time of Moses however accumulating genetic defects made it necessary to prohibit incest.

Potentially a single pair can have 4 alleles for each gene but in most cases probably only 2. We probably started with A and B blood types with type O appearing as a mutation.

Having more than one allele in a population allows adaptation (a change in allele frequency over time). However if an allele reaches 100% then no further adaptation on that gene is possible. E.g white Europeans have lost the alleles to produce black skin and central Africans have lost those for white skin. Each will breed true so long as they marry within their group. However if they intermarry their children can have more diversity on those genes than either parent individually, and their grandchildren can have a range of skin tones.
(Both black and white people have the same pigment, melanin, just in different amounts.)


(Phil) #35

This approach always leaves me uneasy. It assumes there is nothing morally wrong with incest, it is just a practical matter to avoid genetic disease.


(Haywood Clark) #36

You are correct. I should have written “each member of the original pair.”

I don’t think that doubling does much for you. You need an exponential increase.

One HLA gene has >5000 alleles.

Where would they have come from?


(Chris) #37

True, but we also know that immune system genes can have mutations rates orders of magnitude higher than other genes. This isn’t a fault, it’s a feature. As your Wikipedia article says " HLA genes are highly polymorphic, which means that they have many different alleles, allowing them to fine-tune the adaptive immune system."

Noah’s family could have started with up to 10 variants (Noah, his wife, his son’s wives). Adaptive mutation does the rest. Of course they needn’t have had >5000 variants at the time of Abraham.


(Chris) #38

Correct, but as I pointed out Adam & Eve started with zero genetic defects so genetic disease was not a significant problem pre-flood.


(system) #39

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