Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Planet Earth

Numbers: Microbes, From the Tiny Genome to the 70 Trillion in Your Body

By Jeremy JacquotOctober 15, 2009 5:00 AM
microbemedia.jpg
Image: E. coli/Agricultural Research Service | NULL

Newsletter

Sign up for our email newsletter for the latest science news

30 Million  Estimated number of microbial species. Of these, only 70 are known to cause disease. About 1,000 species normally live on the surface of human skin, according to a recent study by the National Human Genome Research Institute.

5x10^30

Estimated number of bacterial cells on earth. More than half of them live buried in marine sediment; about 70 trillion reside in and on your body.

235 Maximum temperature, in degrees Fahr­enheit, at which the most heat-resistant microbe known,

Pyrolobus fumarii

, can multiply. It makes its home in the walls of deep-sea hydrothermal vents. At the other extreme, microbial activity has been detected in permafrost soils in Antarctica at temperatures as low as –4°F.

580,076 Number of base pairs (the twinned “letters” in the DNA code) in the genome of the bacterium Mycoplasma genitalium, making it the smallest known genome of an independently replicating cell. Researchers who hope to create synthetic life are now trying to build this simple bacterium from scratch.

0.000004 Diameter, in inches, of the smallest known bacterial cells, the ultramicrobacteria. An average-size bacterium, such as the E. coli in our digestive tract, is about five times as large. The biggest known bacterial cells, belonging to the coastal sediment bacterium Thiomargarita namibiensis, are 7,500 times the size of ultramicrobacteria. At three-hundredths of an inch, they can be seen with the naked eye.

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In