[Transcriber's Note: This etext was produced from
Galaxy Science Fiction November 1954.
Extensive research did not uncover any evidence that
the U.S. copyright on this publication was renewed.]
Man's family tree was awesome enough to give every galactic
race an inferiority complex--but then he tried to climb it!
In repose, Taphetta the Ribboneer resembled a fancy giant bow on a
package. His four flat legs looped out and in, the ends tucked under
his wide, thin body, which constituted the knot at the middle. His neck
was flat, too, arching out in another loop. Of all his features, only
his head had appreciable thickness and it was crowned with a dozen long
though narrower ribbons.
Taphetta rattled the head fronds together in a surprisingly good
imitation of speech. "Yes, I've heard the legend."
"It's more than a legend," said Sam Halden, biologist. The reaction was
not unexpected--non-humans tended to dismiss the data as convenient
speculation and nothing more. "There are at least a hundred kinds of
humans, each supposedly originating in strict seclusion on as many
widely scattered planets. Obviously there was no contact throughout the
ages before space travel--_and yet each planetary race can interbreed
with a minimum of ten others_! That's more than a legend--one hell of a
lot more!"
"It is impressive," admitted Taphetta. "But I find it mildly
distasteful to consider mating with someone who does not belong to my
species."
"That's because you're unique," said Halden. "Outside of your own
world, there's nothing like your species, except superficially, and
that's true of all other creatures, intelligent or not, with the sole
exception of mankind. Actually, the four of us here, though it's
accidental, very nearly represent the biological spectrum of human
development.
"Emmer, a Neanderthal type and our archeologist, is around the
beginning of the scale. I'm from Earth, near the middle, though on
Emmer's side. Meredith, linguist, is on the other side of the middle.
And beyond her, toward the far end, is Kelburn, mathematician. There's
a corresponding span of fertility. Emmer just misses being able to
breed with my kind, but there's a fair chance that I'd be fertile with
Meredith and a similar though lesser chance that her fertility may
extend to Kelburn."
* * * * *
Taphetta rustled his speech ribbons quizzically. "But I thought it was
proved that some humans did originate on one planet, that there was an
unbroken line of evolution that could be traced back a billion years."
"You're thinking of Earth," said Halden. "Humans require a certain kind
of planet. It's reasonable to assume that, if men were set down on a
hundred such worlds, they'd seem to fit in with native life-forms on a
few of them. That's what happened on Earth; when Man arrived, there was
actually a manlike creature there. Naturally our early evolutionists
stretched their theories to cover the facts they had.
"But there are other worlds in which humans who were there before the
Stone Age aren't related to anything else there. We have to conclude
that Man didn't originate on any of the planets on which he is now
found. Instead, he evolved elsewhere and later was scattered throughout
this section of the Milky Way."
"And so, to account for the unique race that can interbreed across
thousands of light-years, you've brought in the big ancestor,"
commented Taphetta dryly. "It seems an unnecessary simplification."
"Can you think of a better explanation?" asked Kelburn.
"Something had to distribute one species so widely and it's not the
result of parallel evolution--not when a hundred human races are
involved, and _only_ the human race."
"I can't think of a better explanation." Taphetta rearranged his
ribbons. "Frankly, no one else is much interested in Man's theories
about himself."
It was easy to understand the attitude. Man was the most numerous
though not always the most advanced--Ribboneers had a civilization as
high as anything in the known section of the Milky Way, and there were
others--and humans were more than a little feared. If they ever got
together--but they hadn't except in agreement as to their common origin.
Still, Taphetta the Ribboneer was an experienced pilot and could be
very useful. A clear statement of their position was essential in
helping him make up his mind. "You've heard of the adjacency mating
principle?" asked Sam Halden.
"Vaguely. Most people have if they've been around men."
"We've got new data and are able to interpret it better. The theory is
that humans who can mate with each other were once physically close.
We've got a list of all our races arranged in sequence. If planetary
race F can mate with race E back to A and forward to M, and race G is
fertile only back to B, but forward to O, then we assume that whatever
their positions are now, at once time G was actually adjacent to F, but
was a little further along. When we project back into time those star
systems on which humans existed prior to space travel, we get a certain
pattern. Kelburn can explain it to you."
The normally pink body of the Ribboneer flushed slightly. The color
change was almost imperceptible, but it was enough to indicate that he
was interested.
* * * * *
Kelburn went to the projector. "It would be easier if we knew all the
stars in the Milky Way, but though we've explored only a small portion
of it, we can reconstruct a fairly accurate representation of the past."
He pressed the controls and stars twinkled on the screen. "We're
looking down on the plane of the Galaxy. This is one arm of it as it is
today and here are the human systems." He pressed another control and,
for purposes of identification, certain stars became more brilliant.
There was no pattern, merely a scattering of stars. "The whole Milky
Way is rotating. And while stars in a given region tend to remain
together, there's also a random motion. Here's what happens when we
calculate the positions of stars in the past."
Flecks of light shifted and flowed across the screen. Kelburn stopped
the motion.
"Two hundred thousand years ago," he said.
There was a pattern of the identified stars. They were spaced at fairly
equal intervals along a regular curve, a horseshoe loop that didn't
close, though if the ends were extended, the lines would have crossed.