i’m woefully lacking in knowledge in genetics. my understanding is that the result of an inter-species cross, a hybrid, is sterile. is this a rule? i read from somewhere that there was aready a successful mating between a tiglon/liger and a tiger (1/4 lion.) other questions:
how many different named species of animals are there that turn out to be just one species after all?
is there an ongoing effort to disprove my first premise, “all hybrids are sterile and cannot breed?”
i get drowsy whenever i read darwin’s “origin” but i remember him repeating over and over that cross-species breeding is not an impossibility. there is just not experimentation and sufficient control to allow it.
No, it’s just common. As I recall there are even lizard species that are composed of nothing but hybrids; the progenitor of such hybrid species being a female hybrid that as some lizards can was capable of parthenogenesis; breeding without a male.
No, it’s not even generally true. Most interspecies hybrids are fertile to some degree. At one end of the spectrum you get thing like wolf x coyote or cattle x banteng crosses that are 100% fertile. As you move down the line you get things like cattle x bison or cat x serval hybrids that are sometimes fertile then horse x donkey hybrids that are usually infertile and finally the few hybrids that, as far as we know, are always infertile.
The question doesn’t really make much sense.
Species aren’t objectively real. They are just convenient labels that humans put on things. We define what makes a species base don arbitrary criteria and we and we get to change what makes a species. So by that standard no species at all turn out to be just one species. At some future date we may decide to re-assign some animals to another species, but then that will be the new definition of that species. They don’t turn out to be just one species, we just rearranged our arbitrary criteria.
It’s impossible to know how many species might lumped together inn the future, but based on the trend of the last 20 years, we will end splitting far more species than we lump. Genetic evidence has turned up more species that turned out to be multiple species than it has apparent species that needed to be lumped.
There’s no need.
“Origin of Species” contains numerous examples of well documented fertile hybrids. This wasn’t unknown 150 years ago.
There are rather a lot of animal species where hybridization is possible, and while first-generation hybrids are indeed often sterile, many are fertile as well (especially mammals). Males are much more likely than females to be sterile. It’s more of a case-by-case basis.
Often or always fertile first-generation hybrids off the top of my head: female Savannah cats (serval x domestic house cat) and ligers (lion x tiger), male and female beefalo (buffalo x domestic cow), male and female domestic dog x coyote and wolf and also coyote x wolf, and female wholphin (bottlenose dolphin x false killer whale). Most mules (and the vast majority of other horse hybrids) are famously infertile there have been plenty of verified cases of fertile female mules giving birth.
There does seem to be ongoing study of all sorts of hybrids and attempts to breed them, but most often the domestic animals crosses, or naturally occurring hybrids taken from the wild.
There are many genetically distinct sub-populations of animals that are considered one species, and sometimes the status of these sub-populations are changed to be considered separate species. And vice versa.
Determining what makes a species a species isn’t the most exact science.
And when you cross into the botanical side of things, there are intergeneric crosses (like Fatshedera lizei, a cross between Fatsia japonica and Hedera helix). Fatshedera is commonly sterile, but has produced viable seed on occasion, so it’s one of the in-between cases.
And malleable as the definition of “species” is, the definitions of any of the higher-level groupings are even more so. So there’s not really any significance to inter-generic crossings, because we could just as well have defined (say) cows and bison to be the same genus. In fact, I’ve heard it argued that an impartial observer (which we, of course, are not) would probably consider humans and chimps to be in the same genus.
But there is an ongoing effort (for the last few centuries) to improve written communication by the use of Capitol Letters. On this board, we sort of expect that, along with reasonable grammar, spelling, etc.
If you don’t want to do that, perhaps you would feel more at home on some other board – one where the kiddies post using leet-speak and other such silliness.
But frankly, we’d like you to stay here.
Your question was a serious one, with appropriate details, and written in understandable English. Such posters are welcome. Please consider staying.
Capitol Letters is the name of the novel filled with steamy government correspondence I’m writing when I’m done with my current project on interspecies incest.
Big surprise in my aquarium once - a Harlequin Rasbora bred with a Purple Danio. Herman the frankenfish is doing just great after four years. I don’t intend to find out if he’s fertile, but he is certainly enamored of the otto catsthat share his tank. :smack:
Like many hybrids, he’s huge. 4 to 5 times bigger than his parents combined.
ETA: Purple Danio2 First link seems not to be working
