Page #53
MA: Yes of course, it is once again the collision between two different evolutionary currents. Immigration from other countries is sparking a baby boom in some areas while the resident population is declining as a whole. It is an uneven picture. One wave is reproducing and spreading while the other current is falling further and further behind even meeting the fertility rate necessary to maintain their population.
That is what we mean when we speak of differentiation between members of a species. Differentiation in reproductive strategies to the same environment is a pretty telling marker of evolutionary conflict.
Q: I believe that I have a good handle on this subject now; can I summarize what I have heard?
MA: Of course, go ahead.
Q: This discussion originated when we speculated on the future of our species in a changing environment. You have since tried to teach me some of the dynamics involved in making such a prediction.
What I now understand is that from the beginning our species has been subject to at least two different evolutionary strategies involving reproduction, fertility rate and species expansion. Good so far?
MA: Excellent, and especially the part where you say “at least two”, because there are many factors involved - but these two paradigms are easiest to understand. Please go on.
Q: Our current large population numbers are the results of countless surges, crashes and plateaus of population growth. During this long evolutionary development, some varieties of humans have risen to prominence then completely disappeared due to competition from a better adapted group.
MA: There is nothing wrong with the word variety but you might be better served to use the term groups.
Q: Point taken. These surges in population growth by one or more groups are described, by you, as waves.
Q: There have been large waves like the one out of Africa, the one across the Bering Strait and the expansion of the Old World into the new. But there have been lots of smaller waves within those events - like Clovis Man and others. The current wave started after the Black Death and the migration to the New World. That wave (which you and I have been calling the First Wave) rolled across the planet and finally peaked in the early 60’s.
From that time on the rate of increase in the total number of humans has been slowing. However, there are cross currents within that decrease in rate - as there are with many other species. I also understand that there are very distinguishable traits associated with what is called an “r-selected” species, such as early maturity, a large number of offspring, limited or no parental long term investment in these offspring, and that this behavior normally leads to a rapid expansion of that species and a sudden collapse in their numbers.
There are also distinguishable traits associated with what is called a “k-selected” species, such as late maturation, few offspring and a large investiture in those offspring, and that this behavior typically leads this group to fully occupy the habitat, at that point their numbers level off and arrive at some type of balance with their environment.
MA: That is pretty close.
There is one caveat that I should add. In old school Biology we would normally think of any single species as either K or R selected. The understanding that there are multiple expressions of both these traits within any given species, while not controversial, is new. Not a large point but one that could be questioned.
Q: I understand that, although it is difficult to see how you could not see the different strategies in our species.
Page #54
MA: Agreed. OK, now that the first wave is modulating, what else.
Q: Well, there is now The Second Wave rising out of the developing world. As the developed countries have lower and lower fertility rates, other parts of the world are doing exactly the opposite. I am not sure where the rates are the highest but I would guess Africa.
MA: When you look at just births per woman in her lifetime you come up with Niger at 7.19, Guinea at 7.07 and Afghanistan at 7.07. But why is that still misleading?
Q: Because of infant mortality?
MA: Oh, not just that but life expectancy at birth. While fertility may be very high in Niger the life expectancy at birth is only 40 years old. Africa, as a whole, has a life expectancy of around 54 years, but it obviously varies from area to area.
Q: That sounds like exactly what an r-selected group would try to do. In a challenging environment where life is short you try to produce a lot of offspring. Right?
MA: Yes, and that was an excellent summary. As you point out - due to the sub-replacement fertility of much of the industrialized world - population decline is a real factor. Japan, for instance, has been in a state of population decline for a number of years. We know this by using our handy little r=n-m formula. After the 2005 census we discovered (in Japan) for the first time that r was a negative number (meaning that the number of deaths outnumbered the number of births).
But it was to be expected, Japan has the second lowest birth rate in the developed world after only South Korea. That rate of 1.4 is not enough to sustain a population thus r = less than 0. And when r = less than 0, you may have a problem. What do you think?
Q: Well not necessarily. If you are modulating your growth at an optimum level then an r of 0 or slightly less than 0 might be expected.
MA: Yes.
Q: The problem, I suppose, is determining whether you are leveling or plunging.
MA: Population decline, or depopulation, can be cyclic or benign but it is sometimes a harbinger of bad times. Some Japanese towns facing depopulation are offering cash. Yamatsuri offers parents $4,600 for the birth of a child and $460 a year for 10 years. The Republic of Singapore offers $3,000 for the first child, $9,000 in cash and savings for the second; and up to $18,000 each for the third and fourth. Why isn't this option being offered in Europe and other areas with sub-replacement fertility rates?
Q: Because of immigration?
MA: Yes. Were it not for immigration a large number of countries would be facing very serious depopulation issues. In the past decade the UK population level has been rising as fast as it did at the peak of the post-war baby boom in the early 1960s. About 45 per cent of last year’s population rise was brought about by immigration and 55 per cent by a greater number of births than deaths. However the rising birth rate is itself a product of immigration – one in four births last year were to mothers who were born outside Britain.
To summarize, we have the First Wave modulating growth and the Second Wave rushing in to fill the gaps in desirable locations where depopulation is an issue. This immigration results in a rapid expansion of the new group with large, extended families. It would seem a balanced response when viewed in this manor, but it is not.