Why are there many kinds of plants and animals? Why doesn’t the best out-compete, eat, and destroy the others, rising to be the sole dominant species on Earth?
In ecology, a niche is an organism’s specific place within the environment. Some animals eat plants; some eat dung. Some live in the sea; others in trees. Different plants flower and grow in different seasons; some are pollinated by bees and some by flies. Every species has its specific niche.
The Competitive Exclusion Principle (aka Gause’s Law) states that ‘no two species can occupy the same niche’ (or positively, ‘two species coexisting must have different niches.’) For example, if squirrels and chipmunks both want to nest in the treetops and eat nuts, (and there are limited treetops and nuts,) then over time, whichever species is better at finding nuts and controlling the treetops will dominate the niche and the other, less successful species will have to find a new niche.
If squirrels are dominating the treetops and nuts, this leaves plenty of room for rabbits to eat grass and owls to eat squirrels.
II. So I was reading recently about the Parsis and the Travellers. The Parsis, as we discussed on Monday, are Zoroastrians, originally from Persia (modern-day Iran,) who settled in India about a thousand yeas ago. They’re often referred to as the “Jews of India” because they played a similar role in Indian society to that historically played by Jews in Europe.*
*Yes I know there are actual Jews in India.
The Travellers are an Irish group that’s functionally similar to Gypsies, but in fact genetically Irish:
In 2011 an analysis of DNA from 40 Travellers was undertaken at the Royal College of Surgeons in Dublin and the University of Edinburgh. The study provided evidence that Irish Travellers are a distinct Irish ethnic minority, who separated from the settled Irish community at least 1000 years ago; the claim was made that they are as distinct from the settled community as Icelanders are from Norwegians.
It appears that Ireland did not have enough Gypsies of Indian extraction and so had to invent its own.
And though I originally thought that only in jest, why not? Gypsies occupy a particular niche, and if there are Gypsies around, I doubt anyone else is going to out-compete them for that niche. But if there aren’t any, then surely someone else could.
According to Wikipedia, the Travellers traditionally were tinkers, mended tinware (like pots) and acquiring dead/old horses for slaughter.
The Gypsies appear to have been originally itinerant musicians/entertainers, but have also worked as tinkers, smiths, peddlers, miners, and horse traders (today, car salesmen.)
These are not glorious jobs, but they are jobs, and peripatetic people have done them.
Jews (and Parsis, presumably) also filled a social niche, using their network of family/religious ties to other Jews throughout the diaspora as the basis of a high-trust business/trading network at a time when trade was difficult and routes were dangerous.
On the subject of “Madeburg rights” or law in Eastern Europe, Wikipedia notes:
In medieval Poland, Jews were invited along with German merchants to settle in cities as part of the royal city development policy.
Jews and Germans were sometimes competitors in those cities. Jews lived under privileges that they carefully negotiated with the king or emperor. They were not subject to city jurisdiction. These privileges guaranteed that they could maintain communal autonomy, live according to their laws, and be subjected directly to the royal jurisdiction in matters concerning Jews and Christians. One of the provisions granted to Jews was that a Jew could not be made Gewährsmann, that is, he could not be compelled to tell from whom he acquired any object which had been sold or pledged to him and which was found in his possession. Other provisions frequently mentioned were a permission to sell meat to Christians, or employ Christian servants.
External merchants coming into the city were not allowed to trade on their own, but instead forced to sell the goods they had brought into the city to local traders, if any wished to buy them.
Note that this situation is immensely better if you already know the guy you’re selling to inside the city and he’s not inclined to cheat you because you both come from the same small, tight-knit group.
Under Bolesław III (1102–1139), the Jews, encouraged by the tolerant regime of this ruler, settled throughout Poland, including over the border in Lithuanian territory as far as Kiev. Bolesław III recognized the utility of Jews in the development of the commercial interests of his country. … Mieszko III employed Jews in his mint as engravers and technical supervisors, and the coins minted during that period even bear Hebraic markings. … Jews enjoyed undisturbed peace and prosperity in the many principalities into which the country was then divided; they formed the middle class in a country where the general population consisted of landlords (developing into szlachta, the unique Polish nobility) and peasants, and they were instrumental in promoting the commercial interests of the land.
If you need merchants and goldsmiths, someone will become merchants and goldsmiths. If it’s useful for those merchants and goldsmiths to all be part of one small, close-knit group, then a small, close-knit group is likely to step into that niche and out-compete anyone else trying to occupy it.
The similarity of the Parsis to the Jews probably has less to do with them both being monotheists (after all, Christians, Muslims, and Sikhs are also monotheists,) and more to do with them both being small but widely-flung diasporic communities united by a common religion that allows them to use their group as a source of trustworthy business partners.
Over hundreds or thousands of years, humans might not just move into social niches, but actually become adapted to them–Jew and Parsis are both reported to be very smart, for example.
III. I can think of several other cases of ethnic groups moving into a particular niche. In the US, the gambling and bootleg alcohol trade were long dominated by ethnic Sicilians, while the crack and heroin trades have been dominated by black and Hispanic gangs.
Note that, while these activities are (often) illegal, they are still things that people want to do and the mafia/gangs are basically providing a goods/services to their customers. As they see it, they’re just businessmen. They’re out to make money, not commit random violence.
That said, these guys do commit lots of violence, including murder, blackmail and extortion. Even violent crime can be its own niche, if it pays well enough.
(Ironically, police crackdown on ethnic Sicilian control in NYC coincided with a massive increase in crime–did the mafia, by controlling a particular territory, keep out competing bands of criminals?)
On a more pleasant note, society is now rich enough that many people can make a living as professional sports stars, marry other professional sports stars, and have children who go on to also be professional sports stars. It’s not quite at the level of “a caste of professional athletes genetically optimized for particular sports,” but if this kept up for a few hundred years, it could be.
Similarly, over in Nepal, “Sherpa” isn’t just a job, it’s an ethnic group. Sherpas, due to their high elevation adaptation, have an advantage over the rest of us when it comes to scaling Mt. Everest, and I hear the global mountain-climbing industry pays them well for their services. A Sherpa who can successfully scale Mt. Everest many times, make lots of money, and raise lots of children in an otherwise impoverished nation is thus a successful Sherpa–and contributing to the group’s further genetic and cultural specialization in the “climbing Mt. Everest” niche.
India, of course, is the ultimate case of ethnic groups specializing into specific jobs–it’d be interesting to see what adaptations different groups have acquired over the years.
I also wonder if the caste system is an effective way to minimize competition between groups in a multi-ethnic society, or if it leads to more resentment and instability in the long run.