Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

example, in Australia, where the physical separation of many animal species has led to the evolution of animals found nowhere else on earth, such as marsupials like the kangaroo. Human populations, by contrast, are highly mobile, without evolutionary bottlenecks, and are highly intermingled.
    As Gregory Stock of UCLA has said, “ Traditional Darwinian evolution now produces almost no change in humans and has little prospect of doing so in the foreseeable future. The human population is too large and entangled, and selective pressures are too localized and transitory.”
    There are also constraints coming from the Cave Man Principle.
    As we mentioned earlier, people often reject the advances of technology (for example, the paperless office) when it contradicts human nature, which has remained relatively constant over the past 100,000 years. People may not want to create designer children who deviate from the norm and are considered freaks by their peers. This decreases their chances of success in society. Dressing one’s children in silly clothing is one thing, but permanently changing their heredity is an entirely different thing. (In a free market,there probably will be a place for weird genes, but it will be small, since the market will be driven by consumer demand.) More than likely, by the end of the century, a couple will be given a library of genes to choose from, mostly those for eliminating genetic diseases but also some for genetic enhancement. However, there will be little market pressure to finance the study of bizarre genes because the demand for them will be so small.
    The real danger will come not so much from consumer demand but from dictatorial governments that may want to use genetic engineering for their own purposes, such as breeding stronger but more obedient soldiers.
    Another problem arises in the distant future, when we have space colonies on other planets whose gravity and climactic conditions are much different from the earth. At that point, perhaps in the next century, it becomes realistic to think of engineering a new breed of humans who can adjust to different gravity fields and atmospheric conditions. For example, a new breed of humans may be able to consume different amounts of oxygen, adjust to a different length of day, and have a different body weight and metabolism. But space travel will be expensive for a long time. By the end of the century, we may have a small outpost on Mars, but an overwhelming fraction of the human race will still be on the earth. For decades to centuries to come, space travel will be for astronauts, the wealthy, and maybe a handful of hardy space colonists.
    So the splitting of the human race into different spacefaring species around the solar system and beyond will not happen in this century, or perhaps even the next. For the foreseeable future, unless there are dramatic breakthroughs in space technology, we are largely stuck on the earth.
    Lastly, there is yet another threat that faces us before we reach 2100: that this technology may be deliberately turned against us, in the form of designer germ warfare.
    GERM WARFARE
    Germ warfare is as old as the Bible. Ancient warriors used to hurl diseased bodies over the walls of enemy cities or poison their wells with the bodies of diseased animals. Deliberately giving smallpox-infected clothing to an adversary is another way to destroy them. But with modern technology, germs can be genetically bred to wipe out millions of people.
    In 1972, the United States and the former Soviet Union signed an historic treaty banning the use of germ warfare for offensive purposes. However, the technology of bioengineering is so advanced today that the treaty is meaningless.
    First, there is no such thing as offensive and defensive technology when it comes to DNA research. The manipulation of genes can be used for either purpose.
    Second, with genetic engineering, it is possible to create weaponized germs, those that have been deliberately modified to increase their lethality or their ability to spread into the environment. It was once believed that only the United States and Russia possessed the last vials containing smallpox, the greatest killer in the history of the human race. In 1992, a Soviet defector claimed that the Russians had weaponized smallpox and actually produced up to twenty tons of it. With the breakup of the Soviet Union, there is the nagging fear that one day a terrorist group may pay to gain access to