First, old age. Of course, diminishing abilities produce less physically, but in general, animals and plants are quite variable in what could be called natural survival. We have very old trees, occasional old fish, but in general there are many less older individuals, partly due to the fact that any age group can only decrease in numbers, if only by accident. Why keep the old? They are less productive, cannot reproduce, and consume things that younger individuals could use. Without getting into what an old tree might do, mammals generally use elders in a very complicated way. Is the wisdom of accumulated experience and care available to the family more valuable than the costs of keeping the old alive and, at least mentally, contributing? Emanuel’s curve values a 65 year old about the same (in terms of their right to medical care) as a four year old and a 75 year old about the same as a two year old. Peculiar.
Second, youth. Trees and fish produce lots of acorns and larvae. Very few can survive, otherwise filling the earth. Parental care is rare and when it occurs the number of young produced is small. In mammals, parental care is the rule, making each juvenile tremendously more valuable numerically than single acorns or larvae. In humans the juvenile stage is greatly extended, and some would say, now much beyond sexual maturity. Emanuel’s graph does not acknowledge the necessity of protecting this long maturing process. Peculiar.
Modern Eugenics is often thought to have begun with Charles Darwin’s cousin, Sir Francis Galton, who, if he had a political agenda, it is not apparent. Neither did Darwin’s ideas, however later used. Apparently conscripted by later geneticists and activists, eugenics is sometimes identified as a contributor to the development of the social democratic movement, part of it leading to the holocaust. After WWII it seems to have retreated into more statistical demographic treatments, except for the modern environmental movement, which actively still promotes birth and population control.
It seems fair to identify a scientific eugenics, merely a genetical/demographic analysis, and an advocacy/activist portion using at least some of the data for social/political purposes. Which is the Emanuel curve? First it is very simplistic and second it seems directly contradictory to human biology, which places especial value on birth and adolescence. Put in evolutionary biology terms, what is termed the probability that a newborn will survive to a given age, often reproductive, is used by actuaries to determine the expectation of further life. This also can be used to determine what evolutionists call the “Net Reproductive Rate” and “Reproductive Value,” which is what determines the potential for replacement of the population. Reproduction does not occur until maturity, so these values, a somewhat complicated formula, depends heavily on the survival of these non-reproductive individuals. In most animals, including humans, these are relatively high mortality years, especially early. Parental care is highest here, again especially early. The Emanuel curve is the opposite.
Therefore, it is difficult to see the biological basis of the Emanuel curve, especially for the young, perhaps less so for the old. Although other factors (medical, economic) could be involved, the evidence seems to force the conclusion that the curve has little scientific basis, again ethics aside. A maturity/menopause model could be argued as biological, but only in the strict individual physiological sense, ignoring all surrounding factors. The surrounding factors are what the model claims is important as a basis for the ration of medical care, as is also the potential survival of the individual. Therefore, this curve must lie outside the strict eugenics scientific basis, although some argue that control of populations are ecologically necessary.
That is another question.