From FLORIDA ATLANTIC UNIVERSITY and the “now if only climate change could cure the ‘I have a headache’ department comes this study that in the end, attributes change in behavior to “climate change…it is nature’s way to respond”. Oddly, there seems to be some red-team, blue-team, two-timing going on.
First genetic evidence of ongoing mating between 2 distinct species of guenon monkeys
Monkeys see, monkeys do cross species boundary
CREDIT Maneno Mpongo / Gombe Hybrid Monkey Project
A researcher from Florida Atlantic University is the first to document that two genetically distinct species of guenon monkeys inhabiting Gombe National Park in Tanzania, Africa, have been successfully mating and producing hybrid offspring for hundreds maybe even thousands of years. Her secret weapon? Poop.
Prior studies and conventional wisdom have suggested that the physical characteristics of guenon monkeys with a variety of dazzling colors and very distinct facial features like bushy beards and huge nose spots are a function of keeping them from interbreeding. The idea is that their mate choices and the signals they use to select a mate are species specific and that they share common traits linked to their species.
So if their faces don’t match, they shouldn’t be mating, right? Wrong, according to evidence from a novel study published in the International Journal of Primatology.
For the study, Kate Detwiler, Ph.D., author and an assistant professor in the Department of Anthropology in FAU’s Dorothy F. Schmidt College of Arts and Letters, who first studied these monkeys in Gombe National Park in 1994, examined the extent and pattern of genetic transfer or gene flow from “red-tailed” monkeys (Cercopithecus ascanius) to “blue” monkeys (Cercopithecus mitis) due to hybridization.
These two species are the only forest guenons that colonized the narrow riverine forests along Lake Tanganyika that characterize Gombe National Park. They co-exist in the same forests as Jane Goodall’s chimpanzees and baboons. Detwiler identifies hybrid monkeys by their combined markings from both parental species. She estimates that about 15 percent of this population is made up of hybrids, which is very unusual.
Using mitochondrial DNA, extracted non-invasively from the feces of 144 red-tailed monkeys, blue monkeys, and hybrids, Detwiler is the first to show the movement of genetic material from one guenon species to another in an active hybrid zone. After examining the fecal samples, she found that all of the monkeys – hybrids, red-tails and blues have red-tailed mitochondrial DNA – all traced back to female red-tailed monkeys.
For this lineage of monkeys, it is the first time that science shows that not only is the DNA there, but so are the hybrids. Detwiler used mitochondrial DNA because it is more abundant than nuclear DNA in fecal samples, and only comes from the mother – indicating the maternal species in the hybridizing pair.
“There’s a lot of promiscuity taking place in Gombe National Park. Red-tails are mating with blues, blues are mating with red-tails, blues are mating with blues, red-tails are mating with red-tails, and hybrids are mating with everyone,” said Detwiler. “But we’re just not seeing any negative consequences from these two very different species repeatedly mating and producing offspring on an ongoing basis. If the differences in their facial features are so important and signal that they shouldn’t be mating, then why is this happening and why do I keep finding hybrid infants?”
A key finding from the study shows that the blue monkeys in Gombe National Park emerged out of the hybrid population, tracing their origins back to hybridization events between resident red-tails and blues most likely from outside the park. For her control groups, Detwiler collected and examined feces from blue monkeys from a park to the north and a park to the south where hybrids do not exist. These monkeys only had blue monkey mitochondrial DNA.
Detwiler speculates that red-tailed monkeys got to Gombe National Park first and thrived in the environment. Male blue monkeys outside the park had to find new homes after they were kicked out of their groups, which happens when they reach sexual maturity. Sex-driven, they ventured out into the landscape to find appropriate mates – female blue monkeys. Instead, they found the red-tailed females. Apparently, some female red-tailed monkeys were attracted to novel males with different faces and welcomed the sexual advances from these male blue monkeys.
“I keep coming back to the idea that if they are only supposed to mate with their own kind, then why did these red-tailed monkeys mate with the blue monkeys, especially if they had males of their own species around,” said Detwiler. “The female red-tailed monkeys present as willing partners and they are not coerced or forced into copulation with blue monkeys.”
Today, Gombe is an isolated forest habitat. Because they are very social and have had to share close quarters for decades or even centuries, Detwiler believes that they have socially learned that if you grow up in a hybrid group it is okay to mate with everyone.
“The Gombe hybrid population is extremely valuable because it can be used as a model system to better understand what hybridization looks like and how genetic material moves between species,” said Detwiler. “We have this amazing laboratory in nature to help us answer many questions about hybridization and how species boundaries are maintained. This research is very timely because hybridization often occurs in response to environmental changes, as we are seeing with climate change and modified landscapes — it is nature’s way to respond.”
###
Nonsense because the term species has as many definitions as there biologists.
Not quite, but for sexually reproducing species, the definition is pretty robust.
Obviously, these two “species” aren’t, given the standard definition, ie producing infertile hybrids.
Hybridization leading to reproductively isolated species is a common form of speciation. But these monkey hybrids are interfertile with their parent species, so don’t constitute a new species.
This could be the Takeaway message
One aspect of Evolution is driven by the sexual advantages one group has over another.
Petty robust, but not without exception. Even our own species interbred with neanderthalensis. When you get beyond Animalia, the wheels start coming off the definition of species. Not complaining. A useful model. A stepping stone to deeper understanding of the properties of DNA…
Seemed alright on Star Trek the Next Generation. All kinds of inter-galactic hanky panky – Klingon-, Vulcan-, Betazoid-human hybrids and then some. Some o’them planets must’ve had too much carbon in their climate
Neanderthals were IMO simply a subspecies of H. sapiens.
Horses and donkeys are rightly both placed within genus Equus, but are separate species. Likewise, humans and chimps ought to be separate species but not different genera.
The other great apes, ie chimps, gorillas and orangutans, all have 48 chromosomes, but humans have only 46, because two smaller standard ape chromosomes are fused in humans to form our #2. This fusion happens to be associated with erect walking.
more like blue-arse, red-arse in this case.
May be climate change can explain human promiscuity, homosexuality gay marriage and gender confusion too.
gymnospern
Correct about inter-breeding in Europe. Also, there was an as yet unknown humanoid in N Asia that is evidenced in the DNA of a young Mongolian lad who was a cross with Cro Magnon. That DNA is traceable to the current population of Europe through to westward migrations. That humanoid is not a member of a known group, but was definitely there. We have three great ancestor groups. One day we will identify the third. Perhaps it is a relative of the Denisovans.
The big surprise in the Neanderthal DNA was how distant they are as relatives – much father than expected. Yet interbreeding definitely occurred with Europeans having a few % of their DNA still (Amerindians have none of it).
The Earth is a book which shall one day be read.
Actually a lot of species can produce fertile hybrids. All large falcons for example. However in normal conditions they rarely or never do. An isolated, protected, managed, forest patch is not a normal habitat. As a matter of fact it is just the kind of place where you would expect hybridization between closely related species to occur.
And, no, neanderthals was not a subspecies of Homo sapiens. Genetic data shows that male neanderthal/sapiens hybrids were either sterile or had very reduced fertility. After all they and sapiens had been separated for about half a million year which is about average for how long it takes for a new mammalian species to evolve (birds are slower).
All species of the Canis genus are able to interbreed and produce fertile offspring, with the exception of the black-backed jackal and side-striped jackal.
Male offspring of a male leopard and a lioness can be fertile. A male lion and a female jaguar can produce fertile females.
Reproduction is weird.
Crispin,
Perhaps the third group is the Lemur-ians
Infertile?
A specious reference, without cause.
Fertile hybrids within genera are common in nature.
“Kate Detwiler” speculates, as the paper describes it, it an accurate description. Her paper is based on assumptions and confirmation bias blindness.
A) There are other references and studies describing “Cercopithecus mitis” hybrids; including hybrids outside of the Cercopithecus family.
• – a) “Three Sykes’s Monkey Cercopithecus mitis × Vervet Monkey Chlorocebus pygerythrus Hybrids in Kenya”
• – b) “Behavioral Development of Captive Male Hybrid Cercopithecine Monkeys”
Infertile hybrids regarding extra-family crosses is speculated, not proven.
“Kate Detwiler” focuses on mitochondrial DNA, then states that “all traced back to female red-tailed monkeys”; which is to be expected given she depends upon DNA passed from the local females.
Well, duh! Study the feces of pure blue monkeys, find pure blue mitochondrial DNA…
One paragraph from the Behavioral Development paper describes the situation somewhat better than Kate Detwiler manages.
Making Kate Detwiler’s paper another global warming rent seeking alleged research paper.
This guy begs to differ.
“So why do I think humans are hybrids? Well, first of all, I’ve had a different experience from most people. I’ve spent most of my life (the last thirty years) studying hybrids, particularly avian and mammalian hybrids. I’ve read thousands of reports describing them. And this experience has dispelled some mistaken ideas I once had about hybrids, notions that I think many other people continue to take for granted.
For example, one widespread, but erroneous, belief is that all hybrids are sterile. This idea keeps a lot of people from even considering the possibility that humans might be of hybrid origin. The reality, however, is something quite different.”
http://www.macroevolution.net/human-origins.html
And, if they a\have been doing this hybridization for thousands of years, how can it be so blithely linked to “climate change”? Thousands of years suggests that they are hybridizing because of the extended cooling since the Holocene Optimum.
Monkey see monkey do.
My neighbor had a money that loved my head………..every chance he got!
[The mods will exchange your neighbor’s money for a monkey that loves your head – and then (politely) keep the neighbor’s money, should you wish the change …. 8<) .mod]
Perhaps it was looking to get spanked
Perhaps we should be relieved that the thought of bestiality hasn’t occurred to them as of yet. That would truly be interspecies copulation. That might give them some human-like tendencies for sure. How anthropomorphic should you get with monkeys anyway?
Behavior not limited to our fellow anthropoids.
Among the less winning behaviors of the wonderful, green kakapo flightless, nocturnal parrots of New Zealand is an apparently uncontrollable urge to mate with the heads of their human friends.
Not that there’s anything wrong with that.
You should never give head to a monkey, they won’t leave you alone afterwards. Also it is illegal in many jurisdictions.
“Among the less winning behaviors of the wonderful, green kakapo flightless, nocturnal parrots of New Zealand is an apparently uncontrollable urge to mate with the heads of their human friends.”
Must be extremely frustrating for a flightless species.
…..ROTFL!!
And don’t believe a word from that parrot.
Yes. Monkey see, monkey doo-doo, too.
Sure works for dogs.
Push comes to shove I would guess that they are NOT really two species – simply variants within the species with no environmental reason for any specific characteristic to become prominent. But what do I know, I still believe in the definition of species that includes fertile offspring as a necessary requirement. Classically horses and donkeys are separate species because the offspring (mules and jacks) are NOT self fertile. If they were fertile then horses and donkeys would NOT be separate species.
What a crock……..genetic differentiation is not the metric for determining whether two populations are incipient species……. reproductive isolation should be used….and they obviously fail the RI test
….these are not two distinct species
Hey, if you’re desperate for a date, and some gal hoochy-cooches right next to you, what you guys gonna do? Turn her down and hurt her feelings?
Obviously, the scientist doing this study needs to spend more time socializing with her own species. Simians date each other based more on how long it’s been since the last date, and less on.whose nose looks like what.
However, if the scientist occasionally spent some time socializing with her own species, that whole business about what attracts whom to whom might be answered quickly.
Our ancestors were still hybridizing with our chimp kin about a million years after genus Homo appeared. And it’s a bogus genus anyway, since we’re just not that different from out “Australopithcus” ancestors.
Linnaeus himself recognized this fact. Chimps and humans wouldn’t be in different genera is we were anything other than people. Horses and donkeys are farther apart genetically than are humans and chimps.
Chimp wrote:
“Our ancestors were still hybridizing with our chimp kin about a million years after genus Homo appeared.”
Where do you think warmists come from?
Any human willingly hybridizing with a Warmunisto deserves what she gets.
Sara:
“Simians date each other based more on how long it’s been since the last date”, and based on how much they’ve had to drink, and…
,,, “damn those fermented fruits… this guy is coyote ugly… and he’s sleeping on my arm… God I hope I’m not pregnant… if I am I’m going to have a troll.”
[The mods point out that a female troll is, very properly, designated a trollop in most accessible dimensions. .mod]
This thread is beginning to give me a headache. Time to take two Asprin and go to bed…
Alone??
I’d like to point out that monkeys are widely known to get falling down drunk by stealing alcoholic beverages from humans.
Sara- This song should explain it all.
I know they’re socialist fools, but they’re useful fools for this thread.
Oh, yeah! Man, like the 70s never left us, man! Just maintain….
Sara – April 23, 2018 at 6:52 pm
As the saying goes, …….. “Different strokes for different folks”. And most females of the human kind know exactly what those “strokes” are, even though they won’t divulge to anyone but their sexual partner as to what their preferred strokes are. (aka: Revenge Porn Law)
Like I always say, regardless of the species, …… when the individual’s sex hormones “kick-in”, ……. then an uncontrollable reaction means that someone or something is most likely going to get screwed.
Well, this topic clearly needs a little William Shatner, Leonard Nimoy and Frank Gorshin. What happens when one of the black on the right side Charonites mates with a white on the right side Charonites?
Obviously……………….these monkeys have overcome the dreaded “colour problem”
and are now getting along well together !!
Okay… If two faux species interbreed to the extent that all that remains is a single hybrid faux species… How many real species became extinct?
Isn’t it just like us humans to encourage segregation?
Never knew a lower species that knew any difference. There are some…er…religious sects…that don’t seem to care. Is that due to climate change, too, lol?
Because this **never** before mankind started releasing TheMagicMolecule™️ from fossil fuel burning..
And this is another “what is a valid species?” case. I tend to be in the “lumper” category, that minor differences do not make a species. It is a illustrative case, as some regulators are “splitters”,who name a species on minor differences.
What the problem is admitting there are fuzzy rules for naming species, and having zealots admit that fact.
You, sir, have obviously never been a post-grad casting desperately around for an “original contribution.” (Or you were, but in a discipline that actually cares about it being useful.)
I’m confused. Different species can’t produce fertile offspring as hybrids. Since they are “not seeing any negative consequences of two very different species repeatedly mating and producing offspring” are they actually different species? I would have thought infertility would be classed a negative outcome.
Think Mule (sterile hybrid) from a Horse and Donkey, as opposed to Cockapoo (fertile crossbreed) from a Cocker Spaniel and a Poodle.
There is a big difference between a cross-breed and species.
Correct, a young lady and a cucumber will not produce a viable hybrid.
Of course they won’t. A young lady would never marry a cucumber. A young lady will wait for a proper gentleman.
the reason the mule comes up so often is it’s an example of a sterile hybrid. Few other examples exist because .. well, many hybrids are fertile albeit reduced fertility.
Another thing to consider is once a hybrid becomes commonplace we barely even remember it started out as a hybrid. Innumerable plants and birds are hybrids. Even differing number of chromosomes isn’t a divide that can’t be crossed. Look to sheep / goats or goat / other hybrids for more on that. Buffalo and cow too, bison and cow, now I look beyond my botany/zoology lessons at university I see there’s uncountable numbers of examples but always we hear ‘mule’.
Think cockatiel and galah – no one would for 1 minute think they were the same species – their ranges cross and yet hybrids pop up both in the wild and captivity. I’d expect given both species are gregarious and social, only outcasts or isolates would mate to generate the hybrids, and I’d also expect this normal social nature would lead to rejection of the hybrids, reducing their chance at competing as a successful variant of either parent species.
I agree that the “species” label is over-used.
These “species” may very well stick to their own kind by recognizing physical appearances, and somehow deciding to only breed with similar monkeys that look the same. In this story, they puzzle over how one type gets accepted into the social setting of the other type, and thus having a “chance.”
This is pretty well-known, but not explained well here.
In many monkey, and primate, species, and in many other animal species (including wild horses), when males are later-age juveniles, i.e., becoming “men” (who knows – maybe when they begin to grow moustaches or drive really fast in the suburbs), they reach a developmental point where they get kicked out of the tribe. They become loners, “peripheral” monkeys. They drift away from home because they are kicked out.
They wander and eventually find another tribe. They hang out as peripheral males with the new tribe, and may, over time, be able to get physically closer, and eventually become a member of this new group.
At the same time, juvenile males of that group are getting driven out.
Once a male hangs around long enough, and if he gets accepted in the new group, that is all it takes, I believe, to then have a chance of mating. There are male dominance hierarchies in these guenons, but there are weird things where the alpha male is not the only one to mate.
This is what I think is missed in the story. It is not so much the appearance, but somehow these guenons know the dissimilar-appearing primates with whom they might breed – they are not trying to mate with the colobus monkeys or the baboons that are in the Lake Tanganyika area.
It is believed that the kicking out of juvenile males encourages genetic diversity in the “species.” And, the slow acceptance in the next tribe is believed to be a natural form of “quarantine:” if an outsider can only get integrated slowly, he or she will die from the disease they are carrying before they get integrated enough to physically share disease by sneezes, or some new parasite.
Love Has No Labels
Well, it does. There are color judgments (a.k.a. “diversity”). There is political congruence (“=”). It’s notably, selectively exclusive.
Anyway, #NoJudgment. Go for it monkeys. Don’t forget to Plan.
So, they studied these monkeys, found out a lot about them, wrote a paper, and then … were they told that they had to put the words “climate change” into the last sentence in order to be published? That’s how it reads. The reference to climate change has zip to do with the paper, where the monkey business has been going on for donkeys years (monkeys years??).
“This research is very timely because hybridization often occurs in response to environmental changes, as we are seeing with climate change and modified landscapes — it is nature’s way to respond.”
I agree.. The climate change gravy train is: monkey see monkey write about it with ref to climate change of course and then monkey gets banana.
Yes, right on. The nod to global warming reeks of funding, or the hope of.
When cold it shrinks, when hot it ______________.
Seems to be the implicit message.
Years ago, I was talking to a biologist who told me that there are “trends” in what funding committees like to see. (I believe climate change actually was the “trend” used as an example.) You figure out what that is, and regardless of what your project is, you throw in a line that mentions the trend.
With “climate change”, that actually is not too hard to do. Say you want to gather observational data on monkeys. You include a line or two about how you are going to establish their baseline behavior in the current climate, so that the data can be used for predictions and comparisons in the future. Field studies usually gather weather data anyway, so the only additional work you may have is making that data a little more prominent in the resulting paper. Add a sentence or two about potential changes resulting from the coming climate apocalypse, and you are set.
Members of a certain religious group are known to have sex with sheep and goats, which are more distant genetically than other primates. Luckily the unions with goats and sheep have not borne offspring, although I do suspect that there could be such creatures around-leading western nations (to oblivion.)
“HA”, that is only because they have passed Laws prohibiting such fornicating activities.
I think it was elevated CO2 levels acting as an aphrodisiac that is inducing all of that monkeying around.
What do you think? Primate promiscuity? Simian CO2 science?? Or man made monkey business???
Big deal, I see a Huskie getting it on with a poodle.
Should I publish?
🤦♂️
F#*king monkeys!
[The mods do assume that refers to “forking” monkeys, since these actions will create a new purple branch in their evolutionary tree. Er, road. .mod]
Since the climate has been changing ever since the two species evolved, then such interspecies [breeding] must have alway taken place. The climate change we have been experiencing is caused by the sun and the oceans over which mankind has no control. Hence as long as the two species exist they will continue to interbreed and there is nothing that mankind can do about it short of exterminating them all.. So what?
Birds do it,
African bees do it,
And moneys in the trees do it,
So let’s do it!
Go out and cross-breed!
But Victoria Wood did it differently —-
https://youtu.be/lNU5KVa_Tu8
Dirty little devils! It isn’t climate change, it’s all the internet porn they are watching.
Let’s have some positive news Eric. Even though AGW is happening, we can still have a laugh and it’s not all doom and gloom. Earth Day really cheered me up as I am sure it did the rest of the WUWT followers: http://mankindsdegradationofplanetearth.com/2018/04/24/some-positive-news-about-the-state-of-the-planet-it-is-not-all-doom-and-gloom/
Having linked to your site, I see you obtain most of your ‘scientific proofs’ from the media.. like the guardian & BBC; that shows you as a tosser.
The clue is your chosen name ‘I vankin man’
[?? .mod]
Ooohhh … who is in a big tizzy. Both very goid reliable sources who somehow do not appeal to the Trump base. Perhaps a bit too high-brow?
To a troll, a reliable source is any source that says what it wants to hear.
BBC and guardian must be listened and read . Just like “mein kampf” and “The Protocols of the Elders of Zion”.
That is, to understand what powerful people want you to believe, and what they want to achieve
AGW is happening?
Where?
Try this for starters: http://mankindsdegradationofplanetearth.com/2018/03/29/the-sahara-is-growing-due-to-gradual-global-warming/
fake news, ivan. You should really stop trusting your usual source. And stop spreading these fake news.
https://notalotofpeopleknowthat.wordpress.com/2018/04/02/the-sahara-is-growing-even-though-its-wetter-greener/
Otherwise, you will be turned from man to troll, and from troll to stone when then light will come.
Actually, Sahara grew BEFORE global warming scare, and Sahel is new growing greener and creeping over Sahara proper.
https://news.nationalgeographic.com/news/2009/07/090731-green-sahara.html
https://www.cirad.fr/en/news/all-news-items/articles/2011/science/the-sahel-is-getting-greener-natural-vegetation-dynamics
Scientists say :
“The study showed the limitations of trend analyses in remote sensing and climatology, based on linear relations, which are too simplistic to fully reproduce the ecological and geographical phenomena at play. “
So you are approaching the completion of your latest research project, and the grad students are preparing to move on. What to do next? Get the old formula out…….Start the application process……..
“Climate change effect on……………..(fill in the subject)” Monkeys is a good one!
There – done! Another 2 years funding secured.
Um….. I think that paper only refers to the Primates in the Democrat party.
Sex-driven, they ventured out into the landscape to find appropriate mates
=====≠====
not climate change. Clearly these monkeys are hobo-sexuals. Willing to have sex in return for a place to live.
“I keep coming back to the idea that if they are only supposed to mate with their own kind”
Perhaps this somewhat racist interpretation is simply wrong, and nobody has told these monkeys what they are ‘supposed’ to do ?
Climate’s making monkeys grow horns. Imagine that!
I heard that a red monkey had been picked up so many times by a blue monkey that she started to grow handles.
I’d like to point out a difference in humans. We know the consequences of mate selection, at least those of us who can think clearly. Are you advancing and declining? It is to be common and acceptable to speak of good breeding or stock. As society has devolved, so has the ability of many to make good decisions, and the Left has given cultural cover for these decisions and encouraged them.
When longevity escape velocity arrives, I’ve got a plan for the mothers of the ~20 children I’m going to have every century.
The best study I’ve seen in biology in decades … and Detwiler l had to spoil it with a non sequitur blob of climate change feces.
Climate change 101 has one demonstrable fact in its playbook: the tropics remain largely unchanged, even during a glacial maximum. When it does warm, temperatures increase going toward the poles where most of global warming occurs (Arctic Amplification). I have experienced the lack of any change in equatorial Africa east and west over more than 50yrs having worked and lived there. In the1960s, Lagos, Nigeria varied over the year by only 3°C, 25-28°C, this during the galloping ice age cometh scare by some of the same devious actors in today’s heat death guerrilla campaign. I returned to the same boring weather in 1999 and I see that today, it’s the same even though the Lysenkoist have switched to hot air mode.
Umm…have they thought through the bit about climate change, I wonder? So there is going to be more strange and bizarre shagging going on due to carbon dioxide? Are these people working for or against fossil fuels?
More sunshine = more monkey shines.
So, Kate Detwiler objects “red” mating with “blue”. I guess she also objects “white” mating with “black”, or… ?
Perhaps even more scandalous and biologically implausible would be global warming causing shagging between warmistas and denaiyars. A new period setting for Romeo and Juliet?
By any chance are these monkeys involved in fracking ?
Researchers at the Yale School of Public Health have discovered that the rates of two major sexually transmitted infections (STIs), gonorrhea and chlamydia, are 21% and 19% higher, respectively, in Ohio counties with high shale gas activity (“fracking”), compared to counties without any fracking. Rates of a third STI, syphilis, were not elevated.
Here we go…
https://youtu.be/q0POXW4V1_k
Maybe some (or all) of those monkeys are daltonic.
Man-giraffe breeding is NOT an experiment that should be repeated:
https://youtu.be/EHIKEHCXfjU
Based on the differentiation between red-tailed and blue monkeys in this paper, it is clear that in Homo Sapiens, Negroes, Caucasians, Australoids, and Chinese (what is the scientifically correct term for the ‘slant eyed’ human species?) are four different species. As such, there should be no interbreeding and any off-spring of an interspecies mating should be sterile. Result???
One wonders about Darwin’s finches. Allegedly in the various islands they have become separate species and there is no interbreeding. But have scientists tried taking a male of species A and isolating it with several females of species Z? If so, what happened? Did A reject all offers from the Zs? Similarly with that genus of gulls which allegedly encircle the globe, each group able to interbreed with the group next to it, except where the two ends of the chain come together, where they are determined as separate species due to lack of interbreeding.