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."