I understand that there is inheritance of many attributes, a species can get a different color, can get bigger/smaller, stronger or agile, more intelligent ... but in the end it still remains its species!

I don't see how a new species is created with completely new attributes. Anyone can explain to me how metamorphosis/pupation was created evolutionary ... how can such a construct as a cocoon be created evolutionary ... its only of advantage until it finally works, and it takes a very long time to develop something of this kind until it works ...so many tries ... and you actually need a base to start from, but the whole thing has to work including the base to start from, completely unrealistic that this can work I mean ...

I mean just look at real life ... there are 7 billion people right now ...
not one case is known, where a human developed a completely new attribute, a new organ, a new eye, tail and you also don't see a human cocoon. While I believe in the theory of evolution for more or less phaenotypical stuff (size, strength, color, intelligence, etc.) ... I dont see how evolution creates a completely new attribute ...
you also don't see any example of a completely new attribute out there in nature for any species