Bacteria grow and form colonies when given the chance. If food and environmental conditions are favorable, they'll reproduce and form sticky aggregations called biofilms to survive on a variety of surfaces, from rocks in a stream to molars in your mouth.
Biofilms have their perks and problems. On one hand, they're mutually benefiting players in nature. On the other hand, they can be a serious threat. For instance, doctors treating patients with medical implants and devices are especially concerned about biofilms because these surfaces are prime real estate for bacteria. Once colonized, biofilms can produce byproducts that are toxic — and even deadly — to the human body.
Like people in cities, cells in biofilms communicate with one another by sending messages to share information about food availability and potential dangers. But rather than calling their neighbors on the phone, bacteria send memos via chemicals to their nearby friends.
But bacteria aren't afraid to fly solo, either. In fact, some species have developed ways to stick around through rough conditions. When no food is left or conditions take a turn for the worse, these bacteria preserve themselves by creating a tough shell called an endospore, putting the cell in a dormant state that preserves the bacteria's genetic material [source: Cornell University Department of Microbiology].
One scientist even found bacteria in a time capsule that was uncovered and examined 100 years later, while other groups of scientists discovered bacteria dating back to 250 million years ago [sources: Silverman; Vreeland et al.]. This all goes to show that bacteria can self-preserve for a long time.
Now that we know bacteria are colonizers given the opportunity, let's take a look at how they get there through division and reproduction.