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

Here are just SOME of the world’s true bacteria:

Sticker about size

SCIENTIFIC NAME:
Escherichia coli

Elongated cluster of Escherichia

SCIENTIFIC NAME:
Nodularia sp

Cluster of Nodularia

SCIENTIFIC NAME:
Salmonella enterica

Individual Salmonella

SCIENTIFIC NAME:
Staphylococcus sp

cluster of staphylococcus

Guess what?

For perhaps 2 billion years, bacteria were the only living things on Earth! Although some species can cause disease, humans and other organisms need bacteria to survive.

View Another Group

True Bacteria
Protists
Green Plants
Fungi
Cnidarians

Mollusks
Arthropods
Echinoderms
Ray-Finned Fishes
Amphibians

Mammals
Turtles & Tortoises
Lizards & Snakes
Crocodilians & Birds

True Bacteria
Protists
Green Plants
Fungi
Cnidarians
Mollusks
Arthropods

Echinoderms
Ray-Finned Fishes
Amphibians
Mammals
Turtles & Tortoises
Lizards & Snakes
Crocodilians & Birds

BACK TO THE
TREE OF LIFE

Image credits

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Play this game to find out more about the microbes that help and hurt us.

See if you can find the hidden microbes on each coloring page!

Test your knowledge about the bacteria and other microbes that live on and in us.
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.