True Bacteria

KNOWN SPECIES

23,009

0.98% of our world's living things are true bacteria

CHARACTERISTICS

  • microscopic
  • single-celled organisms that lack a membrane-bounded nucleus within their cells

SIZE RANGE

microscopic to about 0.4 inch (0.05 micron to 1 centimeter)

WHERE THEY LIVE

in all environments, including inside other organisms

Image Credits:

Escherichia coli, NIAID; Nodularia sp, © rmatth/CC BY-NC-SA; Salmonella enterica, Medical Illustrator: James Archer/CDC; Staphylococcus sp, Courtesy of Louis de Vos, BIODIC.