Why aren't bacteria taking over the world?

[rakka981]

I need the answer to this question

[mith]

Ever hear of white blood cells?

[alextemplet]

How are you defining "taking over the world"? Bacteria are by far the most numerous life form, and all other organisms depend on them for survival. If bacteria die out, so does everything else. Sounds like they're already pretty dominant to me.

[Chmeee]

"there are approximately five nonillion (5×1030) bacteria on Earth, forming much of the world's biomass." -Wikipedia

The exponent is a 30, on the scientific notation there.

[biohazard]

An interesting question

Competition and lack of nutrition are probably the main reasons - just like with any organisms, and to a much lesser extent inhospitable environments And like mith said, other species are capable of defending themselves.

For example, some eucaryotic unicellular organisms eat bacteria, and bacteria compete for nutrients against one another, as well as against other microorganisms living in the same ecological niche. For example, many molds secrete substances that kill or inhibit bacterial growth.

And even if there wasn't any direct competition by other organisms, bacteria couldn't "take over the world", if by that we mean that they'd cause the extinction of all other life forms and would be the sole survivors on this planet: there'd always be lots of habitats that are inhabitable for bacteria - mainly very dry (or cold) places, where vegetative bacteria survive only when living as symbiots or parasites on multicellular organisms that can survive there. So in other words, even if bacteria could rid the world of other living creatures, it would be against their best interests in many cases, and thus natural selection wouldn't direct their evolution that way.

[miles500]

I would say that bacteria have taken over the world:
In numbers - more bacteria than any other living organism
Geographic - bacteria will basically survive in any place that supports other life and also some places that won't.

As Biohazard rightly pointed out, however, it is far more benefical for bacteria to have other life forms e.g. humans as we are part of the environment (and the world) that some bacteria rely on to exist.

[biohazard]

It all comes down to how you define "take over the world". If it's just numbers, then hell yeah bacteria rule the earth. But if the organism in question has to completely dominate or annihilate all other living creatures on this planet, I don't think any species or genus or whatnot will achieve that any time soon

[AstusAleator]

I can't wait until we can introduce bacteria to some sterile planet and sit back and watch what happens.

[alextemplet]

I can't wait until we can introduce bacteria to some sterile planet and sit back and watch what happens.

We should make a reality tv show out of it and broadcast it across the galaxy.

[biohazard]

Haha, that would be the greatest hit ever! (...for a handful of biologists or such)

Tremble Big Brother!!

[alextemplet]

I was thinking more along the lines of the aliens on Southpark producing a reality show about Earth and broadcasting it across the galaxy.

[canalon]

I can't wait until we can introduce bacteria to some sterile planet and sit back and watch what happens.

Welcome to the Truman show. And no we are not the main characters