Why do Microbes Still Exist?

We all came from microcellular beings. We evoled from tiny beings and now we are what could be considered giants. But what I still don't get is how do microbes still exist? Why aren't bacterias bigger? Why aren't parasitic fungus bigger? Did something went wrong in their evolution? Devolution striked them or something? I would like to know why microbes still exist. And I thank a lot to the person that knows the answer.

BTW: Viruses are non-living so I didn't count them as microbes.

Evolution means to adapt to an environment, not to be "better". Microbes went one path, animals went differently.

Without them, most animals wouldn't even able to survive, so they're necessary for any ecosystem and are more important than most other "better" species in this way.

@maccyd: Ah, now I see. I never though about that. Forgot about the meaning of evolution.

micro-organism are actually more important for life than macro-organisms

Microbes are people too.

...SO LEAVE THEM ALONE!

Pilasy:La Voix d'un homme

Evolution works through random mutation so the members of the species who don't carry the mutated genes will continue having offspring with the original characteristics.

Well, just a few months ago, several helpings of probiotics probably saved my life; I had a severe stomach attack, took some probiotics, and I started to feel better immediately; it was a case of self medicating, but, I'm a scientist too, so.

But, God created microbes for a purpose and macro organisms for a purpose, but, humans were created to have dominion over everything. There's simply no real proof that evolution is actually real (e.g. see all of the data supporting the field a creation science; being unaware of this field makes many falsely assume that evolution is provable), but, as I said elsewhere, I do believe in genetics, as it's a confirmation that God created each organism after it's own kind, and there's real and testable results supporting genetics; I, know, I'm a chemist, so, I just understand genetics a little better, I guess.

Its a matter of surface area:volume ratio. Unicellular organisms exchange substances with their surroundings by diffusion. Rate of Diffusion is determined by Fick's Law. According to this law, rate of diffusion is dependent on the surface area.

When a cell's size is increased, both surface area and volume increase. But volume increases at a higher rate than surface area.

Now as a cell's volume increases, its need for diffusing substances increases.

So unicellular organisms can only grow to the point where their rate of diffusion can keep up with their needs. Some exceptions exist but this is the general rule.

Well, its size would be limited by its host. Generally speaking, only 10% of energy transfers between trophic levels. So it would be impossible for the parasitic fungi to have a higher biomass than their hosts.

Because all organisms occupy a niche. Everything from bacteria to whales have a role in the environment.

Take a look at this example.

The unicellular organisms called phytoplankton are the primary producers in an ocean environment. Something eats the plankton and then something eats whatever ate the plankton and so on and so fourth. But it all starts with the plankton and none of the other organisms involved would be able to exist without them.

@dshipp17:

Can I ask what your stomach symptoms were and what exactly you ate to fix it?

I have stomach/intestinal troubles of my own. Thinking it could be ibs or peritonitis or apendicitis.

Because they feel like it or...

Mutations.

Microbes are the dominant type of organisms on our planet to this day they will survive much, much longer than humans ever will. If it's not broke don't fix it. Microbes are the poster children for survival

Well, the first post is full of many wrong beliefs. Humans didn't evolve from microbes; observational science contradicts this common belief. True, speciation exists (differences between species), but this in no way proves, implies, or leads to full-scale evolution.

God created microbes in the beginning. They exist today because God created them to be survivors for the long haul.