About Microbes

MICROBES DEFINED BY SIZE

The smallest forms of life on Earth are microbes. Although microbes have existed for millions and even billions of years, their presence was not detected until the 17th century. In 1683 Dutch merchant Antony van Leeuwenhoek, who made microscopes as a hobby, detected “wee animalcules” in scrapings from his teeth. Another 200 years would pass, however, before scientists would establish the relationship between microbes and disease.

Although some microbes are deadly, most are harmless and some are extremely beneficial. These microscopic organisms can be found virtually anywhere-in air, water, plants, animals and humans.

Grouped by physical and behavioral characteristics, microbes fall into the following major categories:

Viruses (singular: virus) are the smallest and simplest microbes, just a ball of genes wrapped in a shell-about a millionth of an inch across. No one knows how long they’ve been on Earth or how they evolved. They reproduce, however, by injecting their genes into a cell to produce thousands of new viruses.

Bacteria (singular: bacterium) are much larger than viruses-about one-twenty-five-thousandth of an inch long. If a virus were human-sized, a bacterium would be about as big as the Statue of Liberty. These one-celled bodies either make their own food through chemical processes or feed on live hosts or dead matter. Bacteria have existed on Earth for more than 3.5 billion years.

Protozoa (singular: protozoan) are a group of one-celled predators and parasites similar to bacteria but about 1,000 times larger. Examples include amoebae and paramecia. Protozoa made their debut on Earth more than 1.8 billion years ago.

Fungi (singular: fungus) are a large group of organisms that have cell walls and absorb nutrients from either living organisms or the remains of dead organisms. In nature, fungi are decomposers. They break down matter into nutrients and minerals that plants and animals reuse. Of the 100,000 known species of fungi, familiar examples include mushrooms, yeast, mold and mildew.

In the “Microbes” exhibit, visitors can observe three-dimensional photography of the following disease-causing bacteria and viruses:

– HIV (Human immunodeficiency virus)
Microbe type: virus
Disease: AIDS
Size: to 4 millionths of an inch (0.0001 mm) across

– Ebola virus
Microbe type: virus
Disease: Ebola (hemorrhagic fever)
Size: to 1/25,000 inch (0.0009 mm) long

– Salmonella
Microbe type: bacterium
Disease: food poisoning
Size: 1/5,000 inch (0.005 mm) long

– Streptococcus pneumoniae
(strep-toe-cock-us new-moan-ee-ay)
Microbe type: bacterium
Disease: pneumonia, meningitis, ear infections
Size: to 1/12,500 inch (0.002 mm) across

– Influenza viruses
Microbe type: virus
Disease: flu
Size: varies, to 5 millionths of an inch (0.0001 mm) across

For additional information on this Microbes article, please contact:

Mike Kempf
(210) 599-0045
Mike@evergreenexhibitions.com

Source: Evergreen Exhibitions
http://www.mikekempf.wpengine.com