If evolution is true.....

[ChristianDamien]

Kevin, as a Christian you accept evolution?

[Emily]

Not a fan of discovery.org and neither knew it was a laughing stock. Also, majority beliefs do not always equal truth. Once upon a time most believed the earth was flat.

And look how that turned out.

Discovery is a laughing stock because (it seems) the only other alternative to Darwinian evolution is creation. Even if Darwinian evolution is to be proven 100% false by all biologists tomorrow that doesn't mean that creationism is correct. Discovery.org seems to think ONLY
creationism is correct. They offer no scientific evidence for their claims.

Perhaps I will be back with a list of biologists who reject evolution. Stay tuned.

Cool beans. I just hope there is no quote mining going on. For example. None of this (look at the bottom of that comment. And for reference, read this wiki)

[kevin]

i certainly do accept the theory of evolution, cd.

i'm both an evolutionary biologist and micropaleontologist by training, so i am keenly aware of the science and reasoning behind the theory of evolution.

as an enlightened christian, you will understand that depending upon the bible is untrustworthy due to its errors and editing. so accepting the creation account of genesis is unnecessary.

[Case]

case, to answer your question, i need to know what you think a species is.

is a species a population of interfertile organisms reproductively isolated from other such populations?

is a species a population of organisms distinguished by morphology from the others?

we've bred laboratory populations of fruit flies and beetles that fit the first definition, if i recall correctly, and speciation has been done with radishes and primroses. and dogs and pigeons and so forth fit the second.

okay. let me try to rephrase this (and i'm not a scientist so excuse me if i'm wording things clumsily). so according to the theory of universal common descent all different organisms on the planet come from a single organism. but cats, say, cannot interbreed with dogs, even though they share a common ancestor. so at what point does one group of organisms become unable to breed with another group? and why haven't we replicated that in our own domestication of plants and animals? it would seem as if we've pushed dogs and some species of domesticated plants pretty far from how they existed before humans. but as far as i know one type of dog can still breed with any other type of dog, and broccoli still cross pollinates with cabbage. why would that be?

[ChristianDamien]

Not a fan of discovery.org and neither knew it was a laughing stock. Also, majority beliefs do not always equal truth. Once upon a time most believed the earth was flat.

And look how that turned out.

Discovery is a laughing stock because (it seems) the only other alternative to Darwinian evolution is creation. Even if Darwinian evolution is to be proven 100% false by all biologists tomorrow that doesn't mean that creationism is correct. Discovery.org seems to think ONLY
creationism is correct. They offer no scientific evidence for their claims.

Perhaps I will be back with a list of biologists who reject evolution. Stay tuned.

Cool beans. I just hope there is no quote mining going on. For example. None of this (look at the bottom of that comment. And for reference, read this wiki)

I disagree. Okay, you're an Atheist and you don't believe in a creator, therefore creationism is false.

How about a third possibility? When you speak of creationism, are you referring to the story of Genesis? Or general creation by means of a higher being altogether?

[Emily]

I disagree. Okay, you're an Atheist and you don't believe in a creator, therefore creationism is false.

How about a third possibility? When you speak of creationism, are you referring to the story of Genesis? Or general creation by means of a higher being altogether?

I speak of creationism referring to the story of Genesis. There very well could have been some higher power who did create the Universe. I am open to that possibility. However, when given a specific chain of creation events, like those told in Genesis, I don't agree with. As I told you in another thread I am open to the possibility of a higher power, whatever it is.

About the scientists not accepting evolution thing. Keep in mind that there is such a thing as scientific scepticism. It's not a bad thing at all. To deny evolution is OK in my opinion, as long as they can support why they deny it. But to deny evolution and say that a God created everything instead is not OK because the same reason they claim to deny evolution (their claim that there is no evidence), they haven't presented any evidence to support their claim of a creator.

[kevin]

@Case

you're using interfertility in your definition of species. this is a useful definition for some people, but you can see that its not useful to paleontologists or microbiologists. just sayin

there is usually a gradation between closely related groups of organisms within which the breeding definition doesnt work. horses can breed with donkeys, for instance, as tigers can breed with lions.yet these are separate species. theoffspring are viable but generally sterile.in nature species may be interfertile if vlosely related, and their designation ss one or a,other is somewhat arbitrary. this is natural, and occurs frequently among vertebrates such as frogs and toads. in the end, a species is defined as whatever a competent specialist in the field says it is.

nature is fluid within closely relatef groups. yet reproductive isolation can occur ovrrtime, and had been done in yhe lab with drosophila, flour bertles, algae, primrosez, brassicas (+1 gor knowing what a brassica is) and so on.

[kevin]

. . . Nd dogs are different enough in my opinionto merit separate species status within the groip. you cannot breed chihuahuas and danes, for instance. you can achieve genflow through intermedistes, but in nature they are reproductively isolated.

[Mooby the Golden Sock]

Ok I have a question:

If evolution is a proven fact (like some claim), why is it rejected by many respectable scientists across the world?

It's not.  The number who reject evolution is statistically insignificant, and the number who are "respectable" is far lower.

okay. let me try to rephrase this (and i'm not a scientist so excuse me if i'm wording things clumsily). so according to the theory of universal common descent all different organisms on the planet come from a single organism. but cats, say, cannot interbreed with dogs, even though they share a common ancestor. so at what point does one group of organisms become unable to breed with another group? and why haven't we replicated that in our own domestication of plants and animals?

Excellent questions.

In answer to the first, ability to breed is a continuum.  On one end of the spectrum, you have populations that breed freely and have fertile offspring at normal frequency.  On the other end, you have populations that cannot produce any offspring at all.  In the middle you have populations that interbreed less often than normal, or who produce offspring at lower frequency, or who theoretically can mate but just don't in the wild, or who can interbreed to make infertile hybrid offspring (mules, ligers, tigons, etc.)  It's not like an invisible switch is flipped and suddenly two populations can no longer breed.  Rather, by the time they can no longer breed, it's pretty safe to say that they haven't bred for a long time.

Secondly, we have not replicated the diversity of dogs and cats through domestication because dogs and cats split 42 million years ago, while domestication started about 10,000 years ago.  That's 4200 times as long.  If we keep at it for another 4199 times around, we will probably manage to make several new species.

It is also important to note that time alone does not cause a shift.  If a population changes together, the population will continue to breed.  To get speciation,[nb]The split of one species into two[/nb] you need selection that pulls the population in two different directions.

it would seem as if we've pushed dogs and some species of domesticated plants pretty far from how they existed before humans. but as far as i know one type of dog can still breed with any other type of dog, and broccoli still cross pollinates with cabbage. why would that be?

Dogs existed before humans as gray wolves.  Depending on your source, they are either a separate species from gray wolf or a subspecies.  So we have managed to create a subspecies.

Broccoli and cabbage are of the same species.

[Garja]

Every major creationist group has a statement of faith that essentially states : If evidence that does not support our world view is presented, we ignore that evidence.

This is the very definition of academic dishonesty.  This isn't the position of someone looking for what is true, its the position of someone is trying to assert TRUE, regardless of what the evidence says.

[eyeshaveit]

Every major creationist group has a statement of faith that essentially states : If evidence that does not support our world view is presented, we ignore that evidence.

This is the very definition of academic dishonesty.  This isn't the position of someone looking for what is true, its the position of someone is trying to assert TRUE, regardless of what the evidence says.

This is the position, of someone, who honors the Glory and Majesty of the Lord of Creation, the Holy God of Heaven and Earth, the Eternal LORD; and not one of his subjects; either a mortal philosopher or scientist.

[kevin]

no, it's the position of an idiot who ignores the wonders of god working in the creation and substitutes a fairy tale that god never intended.

[eyeshaveit]

no, it's the position of an idiot who ignores the wonders of god working in the creation and substitutes a fairy tale that god never intended.

Black and white - no gray bob-tailed nag for him.
No straddling the fence - the man puts all of his chips on Mom Nature - the last race on the card.
Baby needs a new pair of shoes - will she get a pair of Golden Slippers or a slick pair of Red Prada High Heels?

[Case]

@Case

you're using interfertility in your definition of species. this is a useful definition for some people, but you can see that its not useful to paleontologists or microbiologists. just sayin

there is usually a gradation between closely related groups of organisms within which the breeding definition doesnt work. horses can breed with donkeys, for instance, as tigers can breed with lions.yet these are separate species. theoffspring are viable but generally sterile.in nature species may be interfertile if vlosely related, and their designation ss one or a,other is somewhat arbitrary. this is natural, and occurs frequently among vertebrates such as frogs and toads. in the end, a species is defined as whatever a competent specialist in the field says it is.

nature is fluid within closely relatef groups. yet reproductive isolation can occur ovrrtime, and had been done in yhe lab with drosophila, flour bertles, algae, primrosez, brassicas (+1 gor knowing what a brassica is) and so on.

@kevin

Wiki says species "is often defined as the largest group of organisms capable of interbreeding and producing fertile offspring." Then it goes on to explain difficulties with that definition. As I said, I'm not much of a scientist. I assumed the above definition without realizing it was at all debatable.

Most of my knowledge about species of domesticated plants comes from farm work i've done. i know brassicas, cucurbits, nightshades, alliums, in their domesticated forms and the wild species that can cross pollinate them. I'm fascinated that plants as diverse as cabbage, kale, collards, broccoli, cauliflower, and brussels sprouts, etc., are all considered to be the same species, Brassica oleracea. Are you saying the reason for this is because these plants have not been isolated enough from each other for an extended period of time? And that if they had been isolated for long enough that they would not be able to produce fertile offspring?

[kevin]

case, i was a systematist, which is the branch of biology that deals with species and classification. there's no one species ddfinition that works for evefybody. as a paleontologist, i couldnt test interfertility of extinct organisms. neither can a micobiologist, becauze protistans genereally reproduce asexually. inthe end, the simplest definition of species willbe those organisms that are physically similar. thats how they were all defined in the past.

cladistics isionly about 30 years old, and is mostly just morphology with assumptionthat physical, chemical, and genetic similarities rdflect a common ancestry. it does not prove common anceztry, it merely assumes that similar organisms are similar because they are relatef. its a premise,not a conclusion.

the  brassicas are a good example of a genus with species that are highly variable within the species. theyve been selected for lines that will breed true, but not necessarily to be intersterile. there is no breeding selection for intersterility, so those traits at cause it are free to drift randomly. maybe in many generations they will have drifted far enougb to be incompatible. maybe not. the key is that

gotta go

[Gnu Ordure]

maybe in many generations they will have drifted far enougb to be incompatible. maybe not. the key is that

gotta go

Kevin, you're such a tease.

[kevin]

i love you too

[kevin]

anyway, the key witb the domestic  brassicas is tbeyve mostly stayed interfertile because the breeders keepbackcrossing them to keep them that way.

in nature things like queen annes lace and carrots will eventually separate enough so that interbreeding becomes less and less successful
so the theory goes

gunson the surface bye

[kevin]

so after msny generationz and either sufficient drift or fixing of chsracters that incidentally made chromosomal recombination lethal or otherwise inhibited successful meiosis, you end up with reproductive isolation.

then you can call it a speciation event, if you haven't already done so based on divergent physical or biochemical or evdn bxhsvioral trait

[kevin]

this high tach telephone mskes me type like the monkey i am. maybe in a milloon years i wil accidentaly generate the cmplte works of shakespearel

[Garja]

Every major creationist group has a statement of faith that essentially states : If evidence that does not support our world view is presented, we ignore that evidence.

This is the very definition of academic dishonesty.  This isn't the position of someone looking for what is true, its the position of someone is trying to assert TRUE, regardless of what the evidence says.

This is the position, of someone, who honors the Glory and Majesty of the Lord of Creation, the Holy God of Heaven and Earth, the Eternal LORD; and not one of his subjects; either a mortal philosopher or scientist.

Really?  Really?  To say that "I believe this, and when ever any evidence contradicts that belief I will ignore it" is a good thing?  With a straight face, you can support that position?

[Case]

in nature things like queen annes lace and carrots will eventually separate enough so that interbreeding becomes less and less successful
so the theory goes

so what kind of evidence do we have that this does in fact happen in nature?

[Garja]

Look up "circular species" (I may be screwing up the term a little). There are examples of newts in California that SHOULD be able to reproduce, but can't.

[Gilgamesh]

Look up "circular species" (I may be screwing up the term a little). There are examples of newts in California that SHOULD be able to reproduce, but can't.

Garja, you're close! Ring Species.

[Garja]

Thank ya- I knew that didn't sound right.

[kevin]

i zlways called them "rassenkreis"

old school

[kevin]

so what kind of evidence do we have that this does in fact happen in nature?

pretty good evidence, actually

increases in genetic isolation are fairly common. st some point the separation merits being called s spdciation event

look up examples of speviation

[Case]

okay. thanks, i have a better understanding of evolution now.

[kevin]

it's a fascinating idea,and explains a great deal.

however, we can't go back into the past, and nothing in evolutionary theory or the fossil record is inconsistent with special creation, assuming the validty of lastthursdayism.

which i think is a logical necessity.

[Case]

what do you mean, kevin?