Not very—at least not on a biological, genetic, or morphological level.
I recently took part in a series of Facebook comments addressing a creationist-inspired link that attacked evolution for, among other things, its failure to produce a single “missing link” between ape and human. The discussion got into the issue of the multiple hominid lines, including the australopithecines and the genus Homo, in which these developments are all cousins and uncles to the H. sapiens species that we call “the human race.”
To me—and I’ve done some reading and study in the area of human origins, as well as genetics and morphology—looking for a single link or trying to define these human predecessors and parallels too closely as to type is a waste of time. In classical evolution, the dividing line between one species and the next is failure to interbreed. First, can a male and female from separate groups produce a viable offspring? And if so, can that offspring breed and produce more viable offspring? Horses and donkeys—both members of the genus Equus—can produce living offspring, but they are almost always sterile. So the two animals are considered to be from different species.
We used to think H. sapiens and H. neanderthalensis were separate species, too. I mean, just look at the Neanderthals, with their arching brow ridges, disappearing foreheads, heavy jaws, and stocky bodies. Such features simply scream “brute.” Shave one and put him in a business suit on the subway, and you’d still think you were looking at some kind of monkey … right? But since we’ve discovered fossil remains well enough preserved to take an almost complete genome, we’ve learned that many modern-day Europeans—humans from the geographic areas where these two “species” overlapped some 20,000 to 40,000 years ago—actually contain about 4% genetic material that is particular to the Neanderthal genome. So not only could the two lineages breed, but they must have produced viable offspring.
Maybe H. sapiens and H. neanderthalensis are subspecies of a wider—and yet to be identified—Homo species. And maybe they are just two sets of human beings with different associated features who can trace their lineage back to a common ancestor in the not-so-distant past.
Looking for distinguishing features and trying to identify all-encompassing “types” is a particularly 19th-century intellectual fetish. It’s probably best reflected in the natural philosophy inspired by the great 18th-century classifier of botany and zoology, Carl Linnaeus. You can see this classifying urge today in birdwatchers, who go to great pains to distinguish various types of jays and woodpeckers. But it can be a trap and lead one to make false distinctions.
In a parallel vein, I’m reading John McWhorter’s The Power of Babel: A Natural History of Language. He makes the interesting point that what we think of as “languages” do not actually exist in natural populations. Instead, what we really have is collections of dialects particular to a certain region. In this way of thinking, Italian, French, and Spanish are simply long-isolated dialects of Latin. And what we today think of as English is actually an amalgam of local dialects, from Yorkshire to Cornish, with the corners rounded off in the studios of the BBC to become “standard English.” Each of these dialects bears some resemblance to the others but has different accents, different vowel and consonant sounds, and different and sometimes peculiar word usages.1
The trend toward identifying a “standard” language started with the rise in literacy after the adoption of moveable type. Most notably, people in the areas we now call Germany, ranging from the North Sea to the Alps, once spoke quite distinct dialects. It wasn’t until Martin Luther translated the Bible in the 1520s and ’30s, and then popularized it with his own brand of Protestantism, that a modern, standard German—called “High German” for its predominance in the southern or higher elevations of the region, compared to the lowlands of places like the Netherlands—developed to unite the country linguistically.
Similarly, in France one finds the langues d’oïl in the northern provinces and the langues d’oc of the southern provinces. The former beat out the latter as “standard” French because of their closeness to Paris, which was the center of culture starting in the Middle Ages and home of the Academie Française with its binding rules on language and grammar.
Just as our notion of a “standard” language is made up of amalgams of linguistic variants that developed in relative isolation in a separate places, so our notion of various human races is made up of amalgams of genetic mutations and morphological features that developed in isolation in different places. The features we now associate with “distinct” races—variations in skin and hair coloring, hair texture, nose shape, eyelid shape, and so on—are all just minor genetic differences that were passed down first in families and then in tribal lineages, and finally came to dominate in the community and the region.
Social structure and the prominence of certain families had a lot to do with it, too. For example, genetic analysis has shown that about 10% of the men living within the borders of the Mongol Empire at the time of Genghis Khan’s death carry his Y chromosome. It was good to be the khan, or king, or a tribal chieftain.
Take skin color, for the most obvious example of race. Various populations in Africa, southern India, and Australia are nearly uniform in having dark skin. This is a natural response to their lineage’s long exposure to tropical sunlight. The regulation of skin pigments and addition of melanin as an inherited trait is a protective reaction against exposure to damaging ultraviolet rays. If you put a Swedish family in the tropics for a hundred generations, they will start having dark-skinned babies, too—without having to invoke any interbreeding to explain the phenomenon.
Fair hair and blue eyes are genetic recessives—that is, they readily give way to brown or black hair and eyes in any genetic mixing. But places like Scandinavia came to be dominated by these recessives because the earliest inhabitants of these cold, far northern areas didn’t travel much and managed to avoid invasion. Then, during the three centuries of Viking raiding and mercantile expansion into western and eastern Europe in the late first millennium, their descendants passed these features on to other populations.
It’s not logical to think of dark-skinned people as belonging to a separate race but blue-eyed blonds as just another type of Caucasian.
Or imagine an island in the Irish Sea where people with red hair and freckles—another set of recessive genes—had become so dominant that you couldn’t find dark-haired, pale-skinned people anywhere on the island. Would we then speak of a separate race of redheads and make them into a special variant of the human race?2
Or if you imagine you can tell a person’s race by features like wide lips or flattened noses, think of the famous Habsburg jaw. This was a genetic feature—a long jaw and prominent chin—in the Habsburg family which ruled in Austria and other parts of Europe from the Renaissance to the 19th century. If that family had started earlier or been more prolific, its famous jawline might have become the distinguishing feature of a whole “race” of central Europeans, similar to Genghis Khan’s Y chromosome.
It's clear from biology that all the beings alive today and accepted as human are of one species and not even variants. Genetically, we all trace back to a band of about a hundred H. sapiens wandering through eastern Africa about 60,000 years ago. On that basis, we are all cousins under the skin.3
1. It’s not surprising that the British Isles should be so linguistically broken. They have seen successive invasions and domination in different areas by the Celts, the Romans, the Angles and Saxons, the Danes, the Norse, and the Norman French. Everybody brought their own words, accents, and other linguistic pieces to the puzzle—the glorious pastiche—that is modern English.
2. However, my daughter-in-law—being red-haired herself—collects memes and anecdotes about “gingers,” as if they were a separate group of people with their own mysterious origins, attractive features, talents, propensities, and special powers. I sometimes wonder if she’s being satirical.
3. Of course, all of this discussion is based on the biological dimensions of race: genotypes and morphologies, which are accidents of inheritance. I’m not commenting on the social and cultural dimensions of race: physical markers by which one person recognizes another whom he or she wishes to accept or reject as an associate. Race as ethnicity and a form of social bonding is a matter of self-definition and choice as much or more than it’s a matter of inheritance. But it’s not biologically significant.