Changes in Animal Populations According to Environment Needs (6 June 2016, 1 Sivan, 5776)
Adapted from "David and Bat Sheva" by Yair Davidiy (2016).
Duration: 23. 03 minutes
Pygmies and Giants
Changes in Animal Populations According to Environment Needs
We do not know what the situation actually was in the time of David. Based on the sources we would suggest that people or at least the Israelites were shorter in height, reached maturity much earlier than they now do and bore children at a young age. Other Israelites were taller and among some of the neighboring peoples were to be found giants and larger specimens in general. Later all this changed and became similar to what it is in our time. The notes below have been culled from other sources. They illustrate the point that we are trying to make. Groups of human beings change according to general needs. this incidentally does something to refute the claims of Evolution. Living organisms change but they do not evolve. They have inbuilt genetic possibilities of adaptation. A change in circumstances may result in the throwing of a "genetic switch" bringing forth specimens that are quite different fromt heir parent bodies. When the situation returns to what it formerly was the change may be reversed or it may not.
The Cane Toad Long Legged Vanguard
Studies of the Hawaiian cane toad (Phillips, 2006) that was accidentally introduced to Australia showed differences between time of movement and migration from one place to another. When for whatever reason a population of cane toads decides to migrate to a new area it generates a vanguard of forerunners. These are the first to lead the others when moving to a new place. They have longer legs and move faster and further. The rest of the toads have shorter legs and come afterwards. After the toads have settled in the longer legged specimens disappear. Their offspring then has shorter legs like all the rest.
More Examples as Provided by Leo M. Spetner:
Rainbow Fish (Guppie) Changes
The alta cichlid fish preys on large mature guppies [rainbow fish]. On the other hand, the killfish preys on small immature guppies.
Guppies that live with the alta mature earlier and produce more and smaller offspring that are less likely to be eaten by the alta. Guppies that live with killfish grow larger so that the killfish are less likely to eat them.
The Aripo River in Trinidad has guppies together with alta. The guppies in that place mature earlier and grow to a smaller size so that the alta will not eat them. D. A. Reznick (1987) and his team took 200 guppies from the Aripo River and put them in the tributary of the river that is home to the killfish but has no alta and had no guppies. The small guppies at first were being eaten by the killfish so their offspring came out as large guppies that the killfish do not eat. Reznick found the changes to be heritable.
The Changing Bills of Finch Birds
In 1967 about a hundred finches were taken from one Hawaiian island and caused to scatter among four other islands that had no finches. Over 20 years the finches increased and multiplied. The finch bill (beak) shapes on each island were different from each other according to the different type of seeds available to feed on. Similar results have been observed elsewhere (Smith, 1987). It is important to note the finches were born with different types of beaks according to the variation in food available. The differences in bills were hereditary even though they had all recently emerged from a common stock.
Changes in Animals and Humans
Limbs that protrude from an animals body have more surface area per unit mass than the rest of the body. In cold weather the animal loses more heat per unit mass from these limbs than from other parts of the body. In many species the tails and legs are shorter for those living in colder climates and larger for those in warmer climates. The wings of seagulls are shorter in cold climates than in warm. Hares and foxes also have shorter ears in colder areas than climates than in warm. Eskimos have shorter arms and legs than do people in warmer climates [Collier et al. 1973: Sumner  found that mice reared at low temperature had shorter legs and tails than mice reared at higher temperatures [Johntson and Gottlieb 1990].
Glogers rule: Races of birds or mammals living in cool dry regions have lighter skins than do races of the same species living in a warm humid area [Schreider, E., (1964)]. This is true of humans as well.
Changes in Height and Sexual Maturity
The Sages (Talmud, Sanhedrin 69b) said that in the time of David women at the age of 7 or 8 bore children. It was emphasized that this was a unique phenomenon that did not prevail in later times. We saw that human beings like animals and plants have the ability to turn genetic switches on and off and on a mass scale give forth offspring more suited to changed environment demands.
One of these options is the need to reach maturity earlier and have children when younger. This usually entails a loss of stature reaching its extreme expression in pygmy peoples as discussed below. In pygmy peoples growth is traded for early sexual maturity. This does not mean that the Hebrews in the time of David were small of stature but it does suggest that this may have been so. Such a scenario would explain several phenomena and also influence our understanding of Biblical events. Paradoxically the causes that bring pygmies into being may also produce giants and people of large bodied stature. Just as in Africa we find pygmies dwelling near other African tribes who are taller than any other peoples so too may such have been the case in the Biblical Era.
Pygmianism may be caused by the need to reach maturity earlier and begat offspring sooner. Side benefits include lower requirements for basic necessities. The notes below show that the same preconditions that bring about pygmianism may also create giants. We know that in Biblical times giants were present. We also know that when compared with some of their neighbors the Israelites considered themselves a very small people (Numbers 13:23, Amos 2:9).
The Island Rule
A supplementary phenomenon to pygmianism, is Island gigantism or insular gigantism. The size of animals isolated on an island increases dramatically in comparison to their mainland relatives. Island gigantism is one aspect of the more general "island rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies. J. Bristol Foster (1964) studied 116 island species and compared them to their mainland varieties. He proposed that certain island creatures evolved into larger versions of themselves while others became smaller versions of what they had been. Both cases may reflect alternate reactions to the same exigencies:
(1) Becoming Smaller.
Large animals can travel further in search of food. They are less vulnerable to predators. They live longer, breed less. Large animals from the mainland who reach an island may be immune from their former predators since the water around them insulates them. They also cannot forage far afield as previously since the island expanse is limited. In times of stress they may have difficulty in feeding themselves. There is no further need for their great size. Smaller pygmy varieties therefore develop. In Ancient times large elephants called mammoths were to be found in cold climates. Pygmy varieties of the great mammoth existed on islands.
Human pygmies may also be explained along the same lines: An organism with a shorter life-span and limited resources becomes smaller and reaches maturity earlier, consumes less and procreates more. This increases the number who can survive on what is available.
Extracts from Wikipedia, "Phyletic dwarfism."
Phyletic dwarfism is the decrease in average size of animals of a species.... Lack of predators of smaller creatures can allow smaller members of a species to survive. Available resources being more beneficial for smaller creatures can also do so. These circumstances are common on islands making Insular dwarfism the most common form of phyletic dwarfism. Examples of this are the Channel Island fox, extinct dwarf elephants of Crete, and Brookesia micra, a minuscule chameleon from Madagascar.
Extracts from Wikipedia, "Insular dwarfism."
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of the reduction in size of large animals over a number of generations[a] when their population's range is limited to a small environment, primarily islands. ... This process, and other "island genetics" artifacts, can occur not only on traditional islands, but also in other situations where an ecosystem is isolated from external resources and breeding. This can include caves, desert oases, isolated valleys and isolated mountains ("sky islands"). Insular dwarfism is one aspect of the more general "island rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies.
There are several proposed explanations for the mechanism which produces such dwarfism.
One is a selective process where only smaller animals trapped on the island survive, as food periodically declines to a borderline level. The smaller animals need fewer resources and smaller territories, and so are more likely to get past the break-point where population decline allows food sources to replenish enough for the survivors to flourish. Smaller size is also advantageous from a reproductive standpoint, as it entails shorter gestation periods and generation times
Among herbivores, large size confers advantages in coping with both competitors and predators, so a reduction or absence of either would facilitate dwarfing; competition appears to be the more important factor.
In tiger snakes, insular dwarfism occurs on islands where available prey is restricted to smaller sizes than are normally taken by mainland snakes. Since prey size preference in snakes is generally proportional to body size, small snakes may be better adapted to take small prey.
Different types of mammoth from islands off the coast of California, of Alaska, of Siberia, of Sardinia, and of Crete.
Different types of pygmy elephants from Sardinia, Creter, Sicily, Malta, Cyprus, and the Greek islands of Nazos, Rhodes, and Tilos .
Types of dwarf stegodonts (a type of elephant) from the Philippines, Flores, Sulawesi, Sumba and Timor.
More examples of dwarf types found on islands included types of deer, tigers, leopards, foxes, wolves, hippopotamus, emus (birds).
Homo floresiensis seems to have been a kind of human being that once existed on the island of Flores in Indonesia. The average height was about 3 and a half feet.
(2) Increasing in Size.
Resources that are too limited and too difficult to attain to allow the sustenance of the usual number may allow a lesser number of larger type to come into being. For example, in simplified terms, an island produces enough for two and a half monkeys but the resources require more effort than usual. Two monkeys arrive. On the mainland the extra food might be absorbed by other elements that are not present on the island. The island effect allows the existence of two monkeys who are each 25% larger than the mainland ones. The added size lessens the extra effort that was previously necessary. Previously there was too much for two (though they had to work hard and take risks) but there was not enough for three. Two that grow larger take up the slack and obtain what they need with more certainty. On the mainland small animals can migrate from one place to another in search of food. On an island they cannot. Small animals on an island have no place to flee. They may be better off growing larger and fewer.
Extract from Wikipedia, "Island gigantism."
Large mammalian carnivores are often absent on islands because of insufficient range or difficulties in over-water dispersal. In their absence, the ecological niches for large predators may be occupied by birds or reptiles, which can then grow to larger-than-normal size.
Since small size usually makes it easier for herbivores to escape or hide from predators, the decreased predation pressure on islands can allow them to grow larger. Small herbivores may also benefit from the absence of competition from missing types of large herbivores.
Benefits of large size that have been suggested for island tortoises include decreased vulnerability to scarcity of food and/or water, through ability to survive for longer intervals without them, or ability to travel longer distances to obtain them. Periods of such scarcity may be a greater threat on oceanic islands than on the mainland.
Territorialism may favor the evolution of island gigantism. A study on Anaho Island in Nevada determined that reptile species that were territorial tended to be larger on the island compared to the mainland, particularly in the smaller species. In territorial species, larger size makes individuals better able to compete to defend their territory.
Smaller islands generally accelerate the rate of evolution of changes in organism size, and organisms there evolve greater extremes in size.
The size and population of wetas [a grass-hopper type insect] are affected by predation. Rats introduced on the mainland began to prey on wetas, reducing their population; wetas shrank in response. On an island isolated from predation, such as Little Barrier Island, wetas have a dense population and have grown to a massive size. Insular species of giant wetas are the only ones not facing extinction. As wetas grow over time, bird predation declines.
Numerous types of giant rats and mice, and other rodents;
The elephant bird, among the largest birds ever, formerly living on Madagascar (extinct).
The extinct moa of New Zealand.
Moa-nalo, extinct giant ducks from Hawaii.
The extinct giant swan Cygnus falconeri of Sicily and Malta
Numerous other types of birds including giant parrots, owls, and pigeons.
Tortoises, lizards, and other reptiles.
Different types of insect.
This rule is most noticeable in islands but it exists everywhere especially in ecologically isolated regions. In mainland environments the ecological vacuums would tend to be filled in other ways before genetical adaptation can take effect. On islands there are no external candidates to devour the surplus. It is interesting to note that in the Ancient World legends concerning giants often located them on islands. There were famous giants in Crete including Titan, and Gigantus. The island of Rhodes was also associated with giants, so too Britain once had giants.
Height in History
In the Bronze Age and later men were often taller and more robust than they are today. Skeletons of the Early Canaanites often show a tall people.
Amos (KJV) 2:
9 Yet destroyed I the Amorite before them, whose height was like the height of the cedars, and he was strong as the oaks; yet I destroyed his fruit from above, and his roots from beneath.
Nevertheless there were times when people were smaller. In the Roman Empire peoples of the Middle East were only about 5 feet tall on the average. Up until ca. 1960 Jews in Eastern Europe on the average were a few inches shorter than the Gentiles around them. Nowadays the descendants of these Jews in the State of Israel and the USA are about the same size as their neighbors and just as tall as East European Gentiles.
The Israelites may also have been much shorter than they are today for much of their history. The Egyptians identified the Israelites with the Hyksos who once ruled over them but later were expelled and went to the area that became Israel. The inhabitants of this area were known as Retenu which may have been a form of the Israelite Tribal name 'Reuben.' Both the Hyksos and Retinu were depicted as of low stature. So too, the neighboring Hittite peoples of northern Syria and present-day Turkey are often depicted with large heads and slightly built smallish bodies.
Causes for low height are often attributed to nutrition but sociological factors as well as the practice of giving birth at an early age may also have been causes. Rational explanations often concentrate on the effects concerning individuals but group influence is also important. It is as if a subconscious consensus among the group decides that for the time being certain changes will take place and so they are. At all events much had been written on the subject and most authorities seem to concentrate on nutrition as a cause for change in height.
The Vikings in the 700s and 800s CE were about 5 feet 8 inches on average.
In ca. 800 CE people were tall. Charlemagne King of the Franks was almost 7 feet tall.
Then height began to diminish reaching a low point in the 1600s. Since then height has increased.
About 200 years ago the average height of Japanese men was under 5 feet. Now it is close to 5 feet 7 inches.
Americans are tall. The Amerindians of the Plains used to be tall before them. The environment has an influence.
"the average height of an American soldier during the Revolutionary War was about 2" more than the average height of the British troops of the time."
The average American man measures in at about 5ft 9 (176 cm), the average Dutch man stands at well over 6 (185 cm) tall. The Dutch are now about the smallest people in the world.
Previously however in the 1800s the Dutch were on of the shortest people in Europe with an average height of ca. 5 feet 5 inches.
The change in Dutch height has been attributed to improved nutrition and social conditions.
See the extracts below:
'The Height Gap. Why Europeans are getting taller and taller-and Americans aren't,' by Burkhard Bilger
# Humans are an ever-improving species, the old evolution charts tell us; each generation is smarter, sleeker, and taller than the last. Yet in Northern Europe over the past twelve hundred years human stature has followed a U-shaped curve: from a high around 800 A.D., to a low sometime in the seventeenth century, and back up again. Charlemagne was well over six feet; the soldiers who stormed the Bastille a millennium later averaged five feet and weighed a hundred pounds. They didn't look like Errol Flynn and Alan Hale, the economist Robert Fogel told me. They looked like thirteen-year-old girls.
# A decade and a half later, after civil war had erupted and up to a million Guatemalans had fled to the United States, Bogin took another series of measurements. This time, his subjects were Mayan refugees, between six and twelve years old, in Florida and Los Angeles. Lo and behold, they were much taller than the Maya in Guatemala, Bogin says. By 2000, the American Maya were four inches taller than Guatemalan Maya of the same age, and about as tall as Guatemalan Ladinos. As far as I know, its the biggest increase of its kind ever measured, Bogin says. It shows that they werent genetically small. They werent pygmies. They were suffering.
The Average Height of Humans Over Time
By Rita Kennedy
Racial and Geographic Differences
People living in different parts of the world exhibited different heights. In the early 1800s, the Cheyenne people of North America were among the tallest in the world, with an average male height of about 5 feet 10 inches. Steckel puts this down to the availability of protein in the form of buffalo. The Cheyenne stood taller than the genetically similar Assiniboine of Manitoba in present-day Canada, but this can be explained by the milder climates enjoyed by the Cheyenne, which enabled them to hunt for longer periods of the year, according to Steckel. Meanwhile, the average height of Japanese men between 1602 and 1867 is estimated at only 5 feet 1 inch.
# Biologists say that we achieve our stature in three spurts: the first in infancy, the second between the ages of six and eight, the last in adolescence. #
# A recent study conducted at Ohio State University, based on skeletal data from 30 previous studies, reveals that men living during the 9th to 11th centuries had an average height of about 5 feet 8 inches. Average height then steadily declined until it reached a low point of 5 feet 5.5 inches in the 17th and 18th centuries, rising again through the 19th century and only reaching prior heights in the first half of the 20th century. An article on the study by Richard Steckel appears in the Social Science History journal. #