Monday, November 28, 2005
Bacteria - by rachel Age 13
Strep throat, cholera, pneumonia, whooping cough. These diseases, and more, are often the only things bacteria get credit for doing. I have researched these microscopic, unicellular organisms and found out that bacteria are responsible for much more than just diseases. There are thousands of kinds of bacteria. Most of them are harmless to humans. There are about two thousand species of bacteria identified, and even more where that came from. It is possible for bacteria to reproduce as often as every twenty minutes. If all the newly formed bacteria survived, there would be about 500,000 new bacteria cells every six hours. That is a lot! Thankfully, this does not happen. Bacteria are the oldest, the simplest, and the most numerous forms of life. Bacteria were here 3.5 billion years ago. A bacterium's structure is quite simple. From the outside in, there is the capsule, the cell wall, and then the cell membrane. Inside is the cytoplasm, which holds the hereditary material, and at times the endospore. There are no intracellular organelles.
Even though there are 2.5 billion bacteria in one gram of soil, you may never see a single bacteria in your entire life. If you lined 10,000 bacteria up, side by side, it would only make up 2.5 centimeters of space and could only be seen under a powerful microscope. Even though bacteria are extremely small, they are found nearly everywhere.
Bacteria are even found in the Dead Sea. For instance, the bacteria that causes acne can be found on a pay phone. There are seven different kinds of bacteria on a locker room shower floor. On a movie theater seat and a school lunch table there are five different kinds of bacteria
Even though bacteria are so tiny, they play a very large role in their ecosystem. Every living thing would not be here today if it were not for bacteria. Decomposing is one of the most important jobs bacteria do. This is also called mineralization. When an organism dies in the wild, it just sits and rots. What is happening is that bacteria are releasing carbon to the atmosphere which plants use. With no carbon dioxide there would be no photosynthesis, which narrows down to Eno food. Instead of this catastrophe, bacteria do us a huge favor. By decomposing the dead organisms, the bacteria release essential nutrients into the air and soil. The simpler material made by decomposition can be used by both autotrophic and heterotrophic organisms. Autotrophs use it to help them make food and heterotrophs use it as food. As you can tell, the bacteria that decompose are very important to the earth's ecology. If these bacteria disappeared, everything would suffer greatly. The cycle goes like this: The grass is eaten by a rabbit. Then the rabbit is eaten by the hawk, then the hawk dies. After the hawk dies, bacteria decompose it and returns it to the grass that the rabbit eats, and it all starts once again.
Another very important job of bacteria is something called nitrogen fixing, or nitrogen cycling. Have you ever wondered why farmers may replant their fields with alfalfa, soybean, or clover in a crop rotation? Well, certain kinds of bacteria called rhizobium live in nodules on the roots of these plants in symbiosis. Rhizobium do the nitrogen cycling. Green plants cannot use the nitrogen in the air, or atmospheric nitrogen. Nitrogen-fixing bacteria (as part of their metabolism) change atmospheric nitrogen into simpler substances call nitrites. Nitrites are needed by green plants. Think about this: In order to make protein, a cow needs nitrogen. This comes from eating grass, which gets its nitrogen from bacteria. Then we eat the cow. So this little chain affects a lot of living things. If there were no nitrogen-fixing bacteria, there would be no plants because the nitrogen in the soil would be used up too quickly. Nitrogen-fixing bacteria helps to replace the nitrogen in the soil so that green plants can survive and flourish. Aren't you starting to feel very grateful to bacteria now? They do a lot of work for us every day. And there is still more.
Vast numbers of bacteria live in our bodies. One example is found in the intestine. This bacteria and humans have formed a symbioses with each other. The bacteria help us with digestion and to produce vitamins. In exchange, they soak up a little extra food for themselves. Neat. Huh? Most dairy products are made by or with the help of bacteria. Some dairy foods are cheese, buttermilk, yogurt, and sour cream. Some other kinds of foods that involve bacteria in their production are pickles and high fructose corn syrup. Can you imagine our soda without high fructose corn syrup, or any other sweet foods for that matter? A hamburger with no cheese or pickles, or chili with no sour cream? The possibilities are endless.
Bacteria help in the production of fuel in two major ways. Some bacteria decompose compost, garbage and sewage and help make methane. Methane is a valuable natural gas. It is used widely as a fuel. Also, over time, the earth's pressure has changed dead and decomposed animals and plants into coal, which is also a widespread fuel.
Bacteria is very important in medicine. Bacteria can actually help to fight themselves. Doctors and scientists have figured out how to use dead or weakened bacteria to prevent other bacterial diseases. This process is called vaccination. Vaccination has helped us all become a lot healthier then we were a hundred years ago. Bacteria also make, or help to make, drugs, hormones, or antibodies.
Bacteria, scientists are discovering, can even help to break down oil to make clean-up after an oil spill easier. This is a big plus for the environment. Scientists are even looking for a use for bacterial-made plastics. In the future, this could be handy and could be broken down easier in the garbage dumps. A group called cyanobacteria produces oxygen. Cyanobacteria is also a source of food. Pink flamingos are one species that feed on cyanobacteria. Lastly, bacteria play a large part in many commercial industries. They help in tanning, making linen, curing tea and tobacco leaves, extracting precious metals from rock, coloring foods, coloring cosmetics, tenderizing meat, removing stains, processing paper, processing cloth, changing one chemical into another, and more!
Bacteria are an extremely important part of your ecosystem. If, for some reason, bacteria could not do their job, or suddenly and inexplicably disappeared, imagine what a mess we would be in. From what I have learned about bacteria, the earth would probably still be the barren wasteland it was 4.6 billion years ago if bacteria had never showed up. Bacteria started everything, and could very well end everything just as quickly. Bacteria do so much for us, where would we be without them?
American Musem of Natural History
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