>The BB theory seems to be a major component of the evolution theory.

Absolutely not.

The Big Bang is the conclusion that because distant galaxies are more red-shifted in frequency the farther away they are (the Doppler effect) that means that space is expanding, and the expansion began from a single explosion at the beginning of time.

Evolution is the conclusion that organisms developed their features as the environment selected the organisms that had a better survival strategy in the environment.

There is no relation.

>So the main stream scientific world has to support it... I guess.

I suspect the Big Bang will fall out the mainstream in the upcoming decades.