Stop procreating, please, for the sake of the human species

The Earth is 29.2 percent land at a surface area of is 148,940,000 km2. Not all of this, keep in mind, is inhabitable by humans (i.e. rocky landscapes, deserts, etc.) Yet, the human population keeps growing in a time when the Earth and its resources cannot necessarily support the human population and the rest of the animal kingdom.

According to the CIA World Factbook, as of July 2008 the world population was estimated at about 6.7 billion people. The echo effect, however, will be taking a toll on the world’s population here soon. The echo effect will be seen in the reproductive rates of the soon-to be-reproducing Generation Y, which roughly consists of those from their mid-20s down to young teenagers, though this can vary by source. The echo effect simply means that though there was a decline in birth rates after that of the Baby Boomer generation, all of the children had by the Baby Boomers will be reproducing soon, and some have already started. This means that a large influx of people will start having consuming children of their own all at once, causing for a large increase in birth rates beyond the average steady increase.

One major factor in the world’s population is that rural populations exceeded those of urban communities. According to the 2007 revision of the World Urbanization Prospects of the United Nations, 2008 marked the first year the urban population rivals that of the rural population. From this point on, the urban population is only expected to increase at a faster rate. This does not suggest, however, that rural and urban populations are evenly distributed throughout different continents. In Asia and Africa, for example, six out of 10 people live in a rural community, and approximately 75- to 78- percent of the world’s population live in a developing or less developed country.

The revised report also says the world’s population will increase by 2.5 billion people by 2050, which some argue is an extremely underestimated figure. Other sources, such as the World Population Awareness non-profit organization (WPA), say the population will double by 2035. Regardless of which estimate most accurately predicts the future of the world’s population, overpopulation hangs over the head of every individual.

What resources are we going to exacerbate with such a large increase? Where are these people going to live and work? While I do not condone or agree with genocide and other non-humanitarian forms of “controlling” the population, the effects of overpopulation on the Earth’s resources, the amount of disease, available food surpluses and poverty all must be examined and evaluated for tactful ways to deter the population growth.
WPA suggests some of the following for every individual/nation:
• Have less children
• Decrease the consumption of all resources
• Recycle more, have better production/disposal of toxic and human waste
• Less urbanization of farmland and depletion of soil
• Less urbanization where water is scarce

If only we were all made up of balanced polymorphisms

© 2007 Rector and Visitors of the University of Virginia
Charles E. Hess, M.D. and Lindsey Krstic, B.A.

Sickle cell disease is present in about 80,000 Americans. It is the most common inherited blood disorder in the United States, though many are only carriers. Being a carrier, however, doesn’t mean there will be the presence of the sickle cell trait.

The sickle cell trait means, in simple terms, the production of abnormal hemoglobin on red blood cells. Hemoglobin distributes oxygen from the lungs to the rest of the body; a means of existence. The red blood cells, if affected by the sickle cell disease become constricted and sickle-like, making it difficult to travel through blood vessels, especially because many can clump together forming clots.

The physical expression of the disease only happens when a person is homozygous for the trait, meaning they have the same two alleles present for the trait. Those who are carriers, are heterozygous for the trait, meaning they only have one allele for the disease that is paired with a normal allele.

In malaria conceiving parts of the world, however, the presence of a sickle cell allele can mean saving their life if they contract malaria.

Malaria lives off of the hemoglobin on red blood cells. A person that has the sickle cell trait (that is, the homozygous form of the trait) will most definitely not be able to get malaria because of the abnormal hemoglobin. However, their chances of survival decreases anyway because the outcomes of expressing the sickle cell trait are lung tissue damage causing acute chest syndrome, stroke, damages to the spleen, kidney and liver, all of which can lower immune system health making the person vulnerable to bacterial infections. A person with the expressed sickle cell trait is therefore selected against in natural selection because of the detrimental affects of the disease.

Because a person is born with it, if homozygous for the disease, many die during childhood. Due to technology, research and preventative drug treatments, some sickle patients have been known to live past the age of 50.

In malarial areas, if a person does not have any alleles for sickle cell disease, then they have no natural way to fight it off, and are therefore selected against via malaria.

In the best of both worlds, however, there is the balanced polymorphism of the trait. A balanced polymorphism is the maintenance of a trait due to the selective advantage of a heterozygote.

The heterozygote for sickle cell disease (again a person who is a carrier) displays a balanced polymorphism. This is because the person does express the trait for sickle cell disease, and are therefore not affected by the trait.

The coolest part of this balanced polymorphism, though, is its ability to still protect people from malaria. If malaria is found in the body, the one allele present for sickle cell disease switches producing the abnormal hemoglobin. Well, if the hemoglobin on red blood cells isn’t available for malaria to support itself and spread throughout the body, then it will die out and rid itself of the body. As soon as it is gone, the allele for the sickle cell trait turns off, and the production of hemoglobin returns to normal.

The carrier is therefore well protected if living in a malarial environment. However, they can pass it on to their offspring, and if two people carrying an allele for sickle cell disease mate, there is a 25 percent chance they will have a child born expressing the sickle cell trait.

African Americans and Hispanic Americans are the most frequent carriers in the United States at one and 12 and one in 100, respectively.

The heterozygous form of sickle cell disease is just one example of a balanced polymorphism displaying the many marvels of human evolution.

More men need the "Good Husband Gene"

Some men are more apt to stay with their wives or girlfriends, or maybe even less likely to engage in a one-night stand. This characteristic brings up the old argument of nature versus nurture. Which one shapes us? Which one makes us who are? Most anthropologists argue it is a combination of both.

Different "love" types have been studied since the days of the Romans. Never before, however, was a love type attributed to human biology — our genetics. It has been assumed that love type was primarily learned through the environment, or through nurture.

A recent study found what might assist biologically what is taught through life in deciding a man's love style.

At the Karolinska Institute in Stockholm, Sweden the department of medical epidemiology and biostatistics did a study on two Swedish twin brothers, according to a Sept. 1 article in the Washington Post. The study found a gene present in males that adjusts and oversees the hormone vasopressin.

Vasopressin is attributed to social motivation. After sexual intercourse vasopressin is released. The hormone activates the brain's reward system, and, according to the study, the more that is present the more the male desires to stick around his mate after ejaculation. The less amount of the hormone present, the less the male is going to want to socialize with his mate after the dirty deed is done.

Differences in the gene between the twin brothers studied in Sweden displayed a connection to how well each one did in their relationships and marriage.

According to Hasse Walum, the lead researcher in the study, a direct relationship was shown in a situation where a man and woman reported they had a "poor bond" with their partner and a certain allele (or variant) of the vasopressin receptor 1a gene was present. The presence of the variant, allele 334, was directly connected to men most unlikely to marry and scored very low on a standard psychological test called the Partner Bonding Scale.

Even worse is for those men carrying two copies of allele 334. These men are twice as likely to encounter a marital crisis or relationship crisis, such as a divorce.

Psychological and relationship tests were given to the males and female partners of the males studied. The women who reported low marital quality, were the same women married to men with the gene variant.

Men in monogamous relationships that do not carry 334 allele see an even more pronounced effect in wanting to be a part of their mate's life long after sexual relations with them. It is not a sexual motivation, but a social motivation.

The study was based on voles that carry the same type of gene and even the 334 variant. Again, the gene was only found in male voles, and no similar gene has yet to be found in females.
"Studies in voles have shown that the hormone vasopressin is released in the brain of males during mating," Walum said to the Washington Post.

The same behavior was displayed in the voles, which prompted researchers to look for the gene in humans, and sure enough there it was, the "good husband gene."

Like all other biological findings, allele 334 is not directly to blame for all the marital problems in this world, though I'm sure men would like this to be the case. Human biology sets out a blueprint for every being, or the nature side of things, but there are always influencing factors once we are born into this world.

Walum also believes this to be true. "Taken together, the effect of the gene variant that we have studied on human pair-bonding behavior is rather small, and it can not, with any real accuracy, be used to predict how someone will behave in a future relationship," Walum said, according to the Washington Post.

So, when hearing about the good husband gene, don't think a pair of good husband jeans can be bought for your slacking, uncommitted partner. DNA can't be changed, and chances are, regardless of whether or not your partner has allele 334 or not, don't expect them to settle down with you too soon. Men are unchangeable.

The findings of the study were published in the "Proceedings of the National Academies of Science."

Revisions made to Neanderthal existence

Neanderthals, mistaken frequently as a direct ancestor to modern humans, diverged from our ancestors long before first theorized. For years it has been said that Neanderthals separated from anatomically modern humans around 400,000 years ago, however, now scientists are agreeing (after years of debate) that the species, Homo neanderthalensis, definitely split 520,000 to as long as 800,000 years ago.

A team of German, American, Croatian and Finnish researchers have been studying remains of 38,000 year old Neanderthal for two years. The bone was found in a Croatian cave.

The evidence is from using mitochondrial DNA (mtDNA), which allows scientists to look much further at the ancestry background than nuclear DNA because it goes practically unchanged generation through generation by the mother. Nuclear DNA is a variation of several sets of DNA, and is what makes each of us individual from the other.

Well, evidence has been surmounting for years that Neanderthals split from anatomically modern humans later than believed, and with increasing advances in using mtDNA this has been easier to prove.

It is still clear that Neanderthals and modern humans could not breed, even during their temporal period of the 10,000-20,000 years that they lived contemporaneously to each other in Europe and parts of Western Asia. If they did breed (which there is evidence of some Neanderthal characteristics mixed with anatomically modern characteristics in other research being done) they could not produce fertile offspring, such as a horse and donkey producing a mule.

It is also still clear that Neanderthals became extinct about 30,000 years ago, which many believe was only due to the sweeping tribes of Homo sapiens. In fact, there is evidence of warfare between the two species, and remains of Neanderthals have been found in living sites of modern humans, often amongst rabbit bone and other midden, suggesting moderns ate them for supper.

Their interaction with anatomically modern humans did not stop at warfare, however, they even traded technology. For example, a Neanderthal tool, the Mousterian tool made "arrowheads" by using soft material, such as bone and antler, whereas years later, not too long before the disappearance of the robust species, moderns came up up with the Chatelperronian tool technique using hard substances, such as stone hammers.

The most mystifying evidence with Neanderthals, however, is their cranial capacity. Anatomically modern humans averaged, at the time of Neanderthals, around 1,100 to 1,200 cm³ while the very robust species' average brain size grew around 1,500 to 1,700 cm³.

The species is suggested by some researchers to have red hair on top of their naturally hairy bodies. The species was somewhat shorter than moderns averaging 5 feet 5 inches for males and 5 feet 1 inch for females. They also had rather large noses and generally robust features selected for cold weather, which can be seen in the picture (from Valley Anatomical Preparations, Inc.).

Some researchers argue that the two species could breed and produce fertile offspring, however, there is not enough Neanderthal genes present in the mtDNA of humans today to theorize that this is true.

Believe it or not ... things change

As an anthropology major one question or subject that people bring up to me the most is the question of evolution occurring today ... is it or is it not?

Just recently I had someone try their hardest to convince me that evolution cannot be real because if it was true then we would see evolution occurring today. Well, this is just a silly statement. The earth is 4.5 billion years old, evolution cannot simply stop – what an anthropocentric idea. 

As John Morley a British politician, writer and newspaper editor almost a century ago said, “Evolution is not a force but a process. Not a cause but a law.”

A large portion of human evolution has been, well, a human process. This does not mean that we are undermining the natural process of things, but throughout the entire history of human evolution, most frontal lobe developments can be attributed to human inventions.

We have not been forcing this, but enthusiastically trotting along. We made tools, which lead to the evolution of labor specialization and culture. Cultures lead us to technological advances.

Computer technology is rapidly rewiring our brains. For example, today most people don’t have excellent or innate wildlife survival skills compared to even a thousand years ago. And now, we have to remember less and less information such as a simple phone number, allowing room and time for other knowledge and even more creative inventions that change the way humans live.

All of these are signs of evolution; human induced, yes, compared to what one normally thinks about upon hearing natural selection, but evolution at its best and more rapid than ever.  

             The most obvious sign of evolution still occurring, however, is modern medicine ... we’re creating powerful diseases and microbes because of our innovative medicines. Antibacterial soap is an excellent example as described by the Center of Disease Control and Prevention website on the effects of overusing antibacterial products and antibiotics. (image from CDC)

" ... after years of overuse and misuse of these drugs, bacteria have developed antibiotic resistance, which has become a global health crisis."

If certain medicines and vaccines weren’t available today natural selection would have had the better of many people that survived only because of the medicine. Look at birth control.

The Pill, introduced in the 60s offered a completely revolutionized role for women. No longer was she expected to be pregnant at a young age, but women could take the Pill, go to college, and do virtually everything that held her back from being truly equal to man.

This has opened up for an entirely different gene pool and way of life.

As Terry Pratchett, an English writer said, “Most species do their own evolving, making it up as they go along, which is the way Nature intended.” 

Don't forget the "short" tales

At the other end of the spectrum are the pygmies. Pygmies are not to be confused with dwarfs. Pygmies "are properly a member of one of certain

(photo: Batwa tribe in Uganda by Graham Rachner) 

small-sized peoples of Africa and Asia, but the word is often used imprecisely to mean dwarf or midget," according to dictionary.com. The word dwarf actually means, "someone checked in growth or stunted, or in some way not normally formed."

Many pygmy cultures in Africa and Asia are completely unheard of. The average adult pygmy height is 4 feet and 11 inches. Most pygmy cultures, however prefer their ethnic name, such as the Aka pygmy group. The Aka group is a nomadic tribe, like pygmy cultures are traditionally. Many live in the areas of Cameroon, Gabon, Republic of the Congo, Central African Republic, Equatorial Guinea and have market relationships with nearby tribes. 

They usually live in small huts made of branches and leaves, typically called a mongulu. Most pygmies are hunting and gathering tribes and many hunting techniques have symbolic meaning or traditions attached to them, such as the big elephant hunt. As well, pygmies do have language, usually it specifically relates to that of the rain forest.

The origins of pygmies is constantly at debate by researchers. Some point to food and resource competition or malnutrition, such as a lack of calcium. Another reaso

n may be simple evolution; adapting the the dense forests and high heat and humidity. 

Below is a map of general locations of pygmy tribes. 

Gigantopithecus--possible explanation for bigfoot "tall" tale

These ancient species could be found where China, India and Vietnam stand presently and date possibly all the way back to seven million years ago until 300,000 years ago.

Their long reign, though impressive, doesn't compare to its infamous height. The genus, Gigantopithecus, stood on average from seven to 12 feet tall, such as pictured at right, a reconstruction at the Museum of Man in San Diego, CA. This giant ape weighed anywhere from 1,200 pounds to one ton.

The genus is a hominoid, meaning it is grouped as a great ape as well as a hominid, which includes strictly bipedal species, or humans. The species is considered a great ape and close relative to modern humans. (These definitions are constantly at debate, but I use them here traditionally.)

It then includes three species of Gigantopithecus, though details of their differences have not yet been discovered. Its closest relative, it is believed, is the orangutan (note there is no 'g' at the end of orangutan, please pronounce it with diligence).

Gigantopithecus blacki is the most known species and is possibly the largest ape species that ever knuckle-walked this earth. Several jawbones have been found, mandibles, and many teeth.

Due to all the teeth found, scientists believe that Gigantopithecus had the same appetite as that of a giant panda. Cavities present in their molars, as they are found in the panda, suggest they ate bamboo, certain vegetables, and because of other wear and tear, seeds and fruits.

The extinction of the species is not quite known. Many suggest simple evolutionary terms and agreements as the reason, meaning as the climate and world changed over the course of their history, other species who were well-adapted to the newer surroundings out ran them in the race for resources. One large contributing factor may have been due to their contemporaneous relatives, Homo.

Homo erectus, dating to two million years ago to 200,000 years ago, had continuous occupation in China and east Asia areas 800,000 to 250,000 years ago (dates are approximate). It is suggested, like many other large mammal species that have lived alongside humans, that Homo erectus hunted the species and may be partly to blame for its extinction.

Critics believe that this species could be the explanation of stories/claims like that of Bigfoot and the Yeti, and may even be an explanation of "dragon bone" use in Chinese apothecaries. However, as folklore goes, even with surmountable evidence, its virtually impossible to clarify or prove it wrong ... as is intelligent design.

Welcome!

As technological advances allow us to learn more about the past, and as more schools are sure to keep theories of evolution in the classroom and creation theories out, there are many misconceptions about human evolution. There are many theories faught over by scientists just as religions have been fighting for centuries. The only thing not disputed however, is what Charles Darwin first claimed in the 19th century: we all come from the same source of life through a process of natural selection.

This blog will be a weekly update on new theories in the world of human evolution and the natural history of humans. Yes, we evolved from a similar ancestor to chimpanzees, and yes, before that our ancestors can be traced to some of the smallest mammals - such as the ancestors of squirrels.