SCIENCE, TECHNOLOGY, & SOCIETY
Science is becoming more and more integrated into our society, bringing with it many questions and few answers. Have you ever stopped to think about how technology has affected your life? In more ways than one. Today, we have vaccines, x-rays, DNA fingerprinting, the Human Genome Project, cloning, artificial selection, and many other applications of our acquired scientific knowledge. (Don't worry, we will talk about some of this later!) Beware that with these advances, come controversy and debate.
Molecules and Cells
Carbon-dating is a useful tool with which scientists may determine the approximate age of fossils. Every radioisotope has a half-life - the time that is needed for half of the radioisotope to decay into its non-radioactive form. 14C has a half-life of 5,730 years. Scientists measure comparative amounts of the radioisotope 14C and the non-radioactive form 12C to estimate the age of fossils.
Technology now allows us to utilize chemicals that will aid in the treatment of a bacterial infection. These chemicals block the active sites of bacterial enzymes, thus inhibiting the bacterium's ability to infect and/or reproduce.
Heredity and Evolution
The Human Genome Project is a worldwide effort to sequence the base pairing of the human genome. Part of the aim of the project is to find the exact position and function of specific genes. Other organisms' genomes are also being mapped to be used for comparison. During the work on the project, additional technologies have been developed that can be used both for this project as well as other projects.
In vitro fertilization
In vitro fertilization has helped many couples to overcome infertility. This method of fertilization involves the fusion of an egg and sperm outside of the woman's body. The zygote can be implanted into the mother's uterus or that of a surrogate mother for development.
Amniocentesis and Chorionic Villus Sampling (CVS)
These two techniques provide the parents of an unborn child with information about the fetus. The child's sex can be determined from a karyotype, and genetic diseases can be tested for.
The use of radiation and chemotherapy to treat cancer is known as immunotherapy. Radiation is used locally, whereas chemotherapy is full body treatment for cancer. These two technologies target rapidly dividing cells; they have been successful in some instances, but not in others.
Gene therapy may be used to treat, but not cure, some genetic diseases. The technology involves the insertion of a healthy gene into a virus or plasmid. The virus may then be introduced into the cells of the afflicted individual in the hopes that transduction will occur. Ideally, the cells with the defective genes will "take up" the corrective gene. This technology has been field tested for Cystic Fibrosis.
In this technology, substances such as DNA fragments or proteins are placed in a viscous gel. An electrical current that is run through the gel, picks up the substances to be separated. Substances separate based on size and charge.
DNA fingerprinting involves the cleavage of DNA strands using restriction enzymes, or endonucleases. The pieces resulting from enzyme digestion are run through a porous gel (gel electrophoresis). The pieces separate according to size. The smaller pieces travel further in the gel. The resulting pattern of bands is characteristic and unique for each person. Comparison of DNA fingerprints can reveal paternity in custody battles, or innocence in a criminal case.
Polymerase Chain Reaction (PCR)
This technology allows scientists to make multiple copies of short sequences of DNA very rapidly.
Transformation of Bacteria
Another application of biotechnology that uses restriction enzymes is the transformation of bacteria. A functioning human gene is inserted into a bacterium. The bacterium will transcribe and translate the gene as if it were its own. Human growth hormone (HGH) and insulin are both produced by bacteria for human use.
Since the advent of antibiotics, many bacteria have become resistant to antibiotics. Continual research is required to produce more powerful antibiotics.
So numerous are the applications of biotechnology that it is impossible to discuss all of them. You should be aware that with all of these applications come several moral dilemmas and concerns. One such issue that is hotly debated today is the issue of cloning. Cloning is the use of asexual reproduction to make an exact copy of an individual. Some of the questions raised include the following:
Organisms and Populations
With our knowledge of genetics and heredity and the demand for more productive beef cattle, more efficient egg-layers and meatier pigs, etc., farmers today are working to selectively mate the individuals with the most desirable traits. The hope is that the offspring will inherit the desirable traits. Artificial selection has been used since the agricultural revolution 10,000-12,000 years ago and is being refined today.
Industrialization and the burning of fossil fuels has led to an increase of CO2 in the atmosphere. Cattle ranching and the need for more paper products has resulted in the deforestation of the tropical rainforests. This increase in source and decrease in sink raises CO2 levels. Since CO2 traps light energy in the form of heat (the Greenhouse Effect), the atmospheric temperature increases (global warming) and this has a large impact on all life. Thermal pollution, water pollution, landfills, and the use of hazardous chemicals both domestically and agriculturally, endangers life everywhere.
Today's technology gives women more control over their reproductive activity. Several methods exist for the prevention of pregnancy.
Early on in the evolution of human civilization, we learned to harness the natural process of fermentation to increase our variety of foodstuffs. The products of fermentation provide us with bread, cheese, and wine. Methane gas (CH4) is being trapped and used for power generation.
The accessibility of drugs today has increased misuse of illegal narcotics, prescription drugs, and non-prescription drugs. We have been able to mimick the body's own chemicals to provide pleasure and enhanced bodily functions and emotions. For example, steroids are used to increase muscle capabilities, but come with some side-effects. Steroids may promote aggressive behavior and in some cases can lead to heart complications. While drugs have improved life for many, addiction and abuse are all too common.
The artificial kidney is one example of the technological advancements of transplants. The pacemaker is also an effective implant that is designed to regulate the beating of the heart.
An example of a transgenic transplant is a heart valve from a pig being transplanted into a human heart.
Living organs can be transplanted with just as much success. Transplants, though, are not as easy as they may seem. Because tissue and blood types must coincide in order for a transplant to be successful, extensive searches must be launched to find a match.
Ethical considerations include cost of the surgery, availability of the organs, eligibility of the recipient, and the accessibility to donors.
Agricultural demands have increased the use of pesticides, such as DDT. However, while these chemicals are effective insect-controllers, they have had unanticipated consequences on other species. Runoff from farm fields percolates into nearby lakes and streams. Microorganisms in the water absorb these hazardous materials which then travel up the food chain (i.e. fish eat the microorganisms and the birds eat the fish.) Top predators such as birds of prey can be adversely affected by this biological magnification.
Overuse of pesticides is leading to insecticide resistance in the insects.
During the Vietnam War, defoliants such as Agent Orange were used to uncover guerillas hiding in the canopy. However, many people were ill as a result of the chemicals.