The Museum of Natural History has amassed thousands of objects - among them the skull of a blue whale and a life-sized kitchen overwhelmed by 130,000 freeze-dried cockroaches - to be unveiled as an ambitious exhibition called "dynamics of Evolution."

Installed as the centerpiece of what is eventually to become a fully reorganized museum, the show commits the Smithsonian to every major scientific concept on the development of organic matter from Darwin's "The Origin of Species" to Watson's "The Double Helix."

"There's nothing really so different about these objects themselves," explains Gene Behlen, the exhibit office chief. "After all, every natural history museum is by definition a collection, among other things, of the evidence supporting Darwin's theory of the origin of life. But to our knowledge this is the first exhibition organized to show how evolution happens. It is more a concept-oriented display than an object-oriented one, and the subject is no less than the variety that separates the species and the variations among them - and, most important, how they got that way."

The most up-to-date techniques of museum display have been lavished on the exhibit: a constantly altering television screen in which a human face changes a feature every second or so: a movie explaining the properties of DNA, an electronic display board; several open dioramas with life-size animals in natural settings and many broad murals and exhibits spaces, accompanied by simple, lucid captions and numberious quotes from Darwin.

"We're not trying to make a big deal with Darwin," says Behlen, "it's just that he was very literate."

Approiately enough, though, in one of of the smaller exhibits there are examples of the differing finches from separate islands in the Pacific's Galapagos cluster where Darwin did much of his research.

But if concepts of evolution no longer seem a touchy subject to the government-supported Smithsonian - 54-years after the other side was upheld at the Scopes trial - there is still opposition.Last year a fundamentalist group named Creationists sought an injunction to bar the exhibit. It was refused in federal district court and is now on appeal.

The Smithsonaian's decision to put together the display originated about five years ago while museum officilas were discussing plans for the next 25 years. "Dynamics of Evolution" seemed a logical first step, says museum director Porter Kier, because "evolution is the one unifying theme in the natural sciences."

It is housed in one of the Smithsonian's largest public spaces, the center gallery leading off the rotunda of the 68-year-old museum. Until the mid-'60s the entire collection of the National Collection of Fine Arts was displayed there.

There are seven subdivisions in the exhibit, and they are meant to be seen in sequence. In the first, a flashing board tells you how may offspring two mates of a species can theoretically produce in eight generations. With cardinals, for instance, it is 13,122 based on the assumption of four eggs a year. With humans, it is 4,114, assuming five young every 15 years.

This is where the freeze-dried roaches come in. The pest-ridden kitchen illustrates what a mere two roaches could do to it in three generations, but for such complicating limits on growth as natural selection - and roach sprays.

Other highlights:

A diorama with two polar bears and a brown bear, showing how two animals once the same species can evolve because of changed environments into different species (though both can still mate, and thus create a hybrid).

Models and maps tracing the life cycle of the hatchings of sockeye salmon, most of which succumb to disease, destruction, predation and starvation, with the result that few, if any, will live to reproduce four years later.

The show is scheduled to continue for 20 years. CAPTION: Picture, Bear exhibit; by Harry Naltchayan