bio

http://www.pioneertelephonecoop.com/~mchumor/00images/3674_biology_cartoon.gif

This cartoon shows a biologist who discovers a talking amoeba. The talking amoeba first says an addition problem, then a subtraction problem and a division problem. The bioligist then quickly smashes it with a hammer and says “I wanted to get it before it multiplied”. This joke refers to the division of amoebas. The basic result of this is that amoeba colonies “multiply”. The joke is fairly accurate, except for of course that amoebas don’t talk and it would be extremely difficult to kill any specific amoeba with a hammer.

Biological measures have long been used to try to control pests in crops. Wasps, frogs, and ladybeetles have all been used to control pest outbreaks in crops. Biopesticides is simply taking this one step further. Biopesticides are naturally occuring fungi, bacteria, or viruses that would be applied in much the same way as chemical pesticides. There are two major practical upshots to biopesticides, they are cheap, and they leave no toxic residue that tends to freak out some consumers at the grocery store. The only problem is that they are slightly less effective than chemical pesticides, and have a shorter shelf life. There is a great potential market for them in consumers who do not like the idea of chemical pesticides, but aren’t willing to fork over the extra cash to get organic products. Also they are much safer for the environment. They have little or no effect on any other than the target organisms, and the huge benefit of no toxic runoff that is such a large problem in chemical pesticides. While biopesticides are unlikely to phase out chemical pesticides any time soon, it is certain that they will play a larger role in our agriculture in years to come.

Evolution is essentially natures form of an arms race. It is a competition to see which species can adapt the best to their environment. Which predator can develop the most efficient techniques of catching prey, which prey can come up with the best defense. It is interesting to note, then, that for the first time in natural history, there is a species for which further evolution is unlikely to occur, and unlikely to be needed. I am talking of course, about humans. We no longer need to outrun our predators, or even be the most skilled hunters. We no longer need to be naturally hardy enough to survive childhood diseases, we are vacinated for them, or they are treated by modern medicine. Food is served to us, not hunted for. Stupid people’s survival rate is just as high as intelligent people, as is, unfortunately, their reproduction rate. Despite what the Darwin awards might make you think, there is too little natural selection in the human race to make any signifigant changes to our genome. Does this mean that nature has finally created the perfect species? Of course not. There is immense room for improvement in the human genome. People are still born with diseases, bad eyesight, and a thousand other problems that in any other species might stop them from reaching breeding age. All it means that we are incredibly unlikely to evolve anything like wings or heat vision any time soon.

 http://discovermagazine.com/1992/aug/has…

Salt Cedar, or Tamarisk, is an invasive species that has taken over the riverbanks in many areas of the midwest. They can live in areas with salinity up to 15,000 ppm. The main problem with Salt Cedar is its disruption of the natural aquatic systems. Their roots are deep enough to penetrate into the water table and a single tree can consume upwards of 250 gallons a day (the average American Household uses just under 100 gallons a day). They outcompete native plants and deprive the soil of the nutrients necessary for anything else to grow. They have actually become a problem for farmers in Texas, where the already devastaded Rio Grande is being further drained by these infestations of Salt Cedar.

There are many methods developed for controling infestations such as these. Chemical agents have been the most effective against large infestations. A biological, and perhaps more longterm, solution is the introduction of insects that will feed upon these salt cedars. There are fifteen of these insects being investigated and two of these a mealy bug (Trabutina mannipara) and a leaf bug (Diorhabda elongata) are expected to soon be approved for release. There is much debate over the introduction of new species, basically because it was the introduction of new species that caused the problem in the first place. More importantly there are fears that even if the tamarisk tree is sucessfully controlled, native plants may not be able to return because of the massive havoc that the tamarisk tree wrecked on the soil.

Sources:

http://www.nps.gov/plants/ALIEN/fact/tama1.htm

For thousands of years people have been struggling to produce enough food to feed themselves. Thanks to recent advances, however, the problem is not that we do not have enough food, it is its distribution. The most recent of these advances is the genetic modification of crops. We can now grow, among many other things, corn that produces its own insecticide, tomatoes that hardly ever rot, rice with high levels of vitamin A, and soybeans that aren’t killed by herbicides. These advances produce higher yields in crops with less effort. Up to 75% of all processed foods in America contain some sort of genetic modification. 89% of the total soybean crop, as well as 83% of cotton and 61% of maize grown in America is genetically modified.

Genetic modification of crops is carried out by injecting the parts of the DNA code of other organisms which contain the desired traits into the DNA code of the crop. For example, insecticide producing corn contains the DNA of the bacteria Bacillus thuringiensis, which produces an insecticide. The real difficulty in genetic modification lies in determining what part of the DNA codes in organisms do what. After that it is a simple matter of implanting them in the desired organism.

As seen with any sort of genetic modification, people have raised concerns as to both the ethicallity and safety of these genetically modified foods. The major saftey concern is about the simple lack of testing. There is no known scientific reason why these Genetically modified plants should be more dangerous than their none modified versions, but many people believe they should not be put into such common use until they are very thouroughly tested. As for their ethicallity all I can give is my opinion. Humans have been indirectly genetically modifying plants for long before what they new what genes were. For thousands of years humans have replanted the wheat with the largest and most grains and corn with the highest yields and best taste. Make no mistake this was not natural selection, it was the breeding of crops. It is likely that we would not be nearly as comfortable as we are now if we had not done this. I find it hard to argue that genetic modification is much different. The only difference is we can do it more effectively.

http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml                                                      http://www.gao.gov/docdblite/summary.php?accno=A03410&recflag=&rptno=GAO-02-566

Antibiotic resistant strains of bacteria are a rising problem in hospitals today. Long gone are the days when penicillin was a cure all for infections. The problem lies in the rapid reproduction of bacteria. While it takes any living thing many generations to make any significant adaptation, bacteria’s generations are measured in hours, not decades. In short bacteria are evolving resistances to our antibodies faster than we can create them. For example, between 1979 and 1987 only .02% of pneumococcus strain bacteria were resistant to penicillin. by 1994 that number had skyrocketed to 6.6%, making penicillin effectively useless against it. In seven years, a strain of bacteria had beat an antibody. While the resistance of a bacteria to any specific antibody is a problem that can be dealt with, the problem lies in that these bacteria can evolve so fast that many strains are becoming resistant to several different antibodies. We are having to resort to less and less safe antibodies. Vancomycin, considered an antibody of last resort by most doctors, side effect’s include kidney failure. What is scarier than that is that there are already reports of strains of bacteria resistant to vancomycin. In fact, there are already strains of bacteria resistant to all approved antibodies. In many cases doctors are having to resort to experimental drugs in hope of curing a patient.

As bad as this problem is however, a crisis can be postponed, if not entirely avoided, if a few simple steps are followed. One of these steps is to stop the overprescription of antibodies. There are still doctors in this country who prescribe patients penicillin for a common cold. The common cold is a virus, and therefore not effected by antibodies. All this can serve to do is increase the resistance of any other bacteria that happen to be around in that patients body. Also patients need to take their medicine as prescribed. Do not stop taking an antibody when the symptoms disappear. All this will do is allow for the remaining bacteria, which are probably partially resistant to the drug, to evolve and reproduce. Using more targeted antibodies for specific bacteria strains will also help. This way the other bacteria in the body do not become more resistant to “broad spectrum” antibodies such as penicillin. 

Bacteria resistance is a problem to which there is likely no possible solution. They were here long before us, and if the past hundred years is any indication, they will be here long after us. This does not mean that we are all going to be wiped out by disease and infections anytime soon, or at all. It simply means that for the foreseeable future people are going to keep getting sick and dying from bacterial infections.

References

Lewis, Ricki. “The Rise of Antibiotic-Resistant Infections”, www.fda.gov

“What doesn’t Kill them makes them Stronger” http://whyfiles.org