Why are bacteria single-cell organisms?

To make their living and they have been created like that

Why are bacteria single-cell organisms?
They are single celled bcoz god made them like tat......wat xactly u wanna ask?
Reply:Erm... Bacteria is small...


So...


It has to be single-cell so that diffusion of nutrients and gases between it and it's environment is easier.
Reply:Because when bacteria evolved, they were able to best survive in the existing environment (survival of the fittest). They are still around because in the present day environment, they are still able to survive. They have their own "niche".





Genetically, and in terms of survival today, they are not able, or not benefitted (in survival terms) by expressing the genes that would allow them to become multicellular.
Reply:Bacteria are microscopic organisms whose single cells have neither a membrane-bounded nucleus nor, other membrane organelles like mitochondria and chloroplasts. Another group of microbes, the archaea, meet this criteriabut, are so different from the bacteria in other ways that they must have had a long, independent evolutionary history since close to the dawn of life. In fact, there is considerable evidence that we are more closely related to the archaea ( may be the oldest life forms on earth. They are prokaryotes) than they are to the bacteria. I hope that this is useful. Here's a great web:


http://users.rcn.com/jkimball.ma.ultrane...

night jasmine