Charles Darwin would be astonished at what is happening in the Galapagos--Ecuador's Pacific islands 600 miles off the coast which inspired his ''On the Origin of Species.''
There he observed what he called ''the aboriginal creations found nowhere else.'' Now he might wonder whether they can continue to survive.
When Darwin stopped there in 1835 as a fledgling naturalist on HMS Beagle, he recorded in his journal that he ''met two large tortoises, each of which weighed at least 100 pounds,'' and only a handful of people. They were members of a penal colony and some Spanish whalers who had come to dry fish and salt tortoise meat.
Today there are 5,000 Galapageians living on four of the 13 major islands. The few remaining giant tortoises, for which the islands are named, have retreated to the moist tops of volcanic slopes. Furthermore, Darwin's ''strange Cyclopean scene'' of ''antediluvian animals'' and ''black basaltic lava thrown into the most rugged waves'' has become a vacation spot for thousands of tourists, challenging efforts to preserve the original flora and fauna.
Conservationists now talk apprehensively about such proposed projects as a gambling casino, oil depots to service transpacific traffic, a desalination system for the waterless areas, a third airport, even a Club Mediterannee. However, the infrastructure to handle merely an increase of shipboard visitors constitutes a greater threat, because it is more imminent.
With tourism growing steadily, the Ecuadorean government is limiting access this year to 25,000 people. The Galapagos National Park permits only three cruise ships into the area, plus a few charter boats. The latter are floating hotels from which trained guides escort small groups onto the islands.
UNESCO, which helped structure the park, has recently declared it a World Heritage. However, Prof. Fernando Ortiz of Quito's Catholic University, who is a biologist and member of the high-level Presidential Commission for Studying Tourist Impact in Galapagos, has called government policy ''pretty erratic.'' It causes concern among conservationists about additional money given to the newly designated province, he said. ''The fear is that the funds will be used to attract tourist hotels rather than improve the quality of life,'' Professor Ortiz explains.
The commission has recommended that the status quo be maintained, lest the fragile ecosystem be destroyed. This recommendation, however, has not yet been approved by Ecuadorean President Hurtado. Meanwhile, the government airline (TAME), which flies from Guayaquil to Baltra Island, is flying two new planes which double the tourist capacity.
Protesting such inconsistencies, a marine fisheries expert has left his position at the government Instituto Nacional de Galapagos (INGALA) because, he says, ''I am not prepared to defend ecologically oriented politics which are a pretext for development.'' The interest in the Archipielago de Colon (official name) that began with Darwin has had far-reaching effects.
In addition to such celebrities as Agassiz, Beebe, and Roger Tory Peterson, an ever-widening circle of naturalists has come to ''Darwin's laboratory.'' As zoologist Roger Perry has written, ''Evolution can be found anywhere, but in Galapagos its simplicity makes the evidence compelling.'' Just recently, two biology professors, Elizabeth Boyd (emeritus) and Susan Smith of Mount Holyoke College, led a group of academics, alumnae, and students to the remote oceanic sanctuary. There they discussed the effects of man's intrusion.
"Tourists in quantity, by unknowingly walking on the lava under which Audobon's shearwaters and stormy petrels nest, can destroy the eggs, just as they did a large number of iguana eggs in 1980,'' said Dr. Boyd, who is a distinguished ornithologist with a genus and species of bird parasites named for her. ''On the other hand,'' she reasoned, ''after taking basic courses in zoology which end up with Darwin, instead of going to a laboratory and looking down a microscope, why shouldn't students come to Galapagos and see for themselves?''
What most concerns those interested in the relatively young volcanic islands is the unique wildlife. Professor Ortiz says reassuringly that this ''won't disappear, thanks to the Charles Darwin Scientific Station.'' On the remote island of Santa Cruz, two days by boat from Ecuador, Dr. Friedeman Koster, director of the Estacion Cientifica Charles Darwin, contemplates the ecological problems of the giant tortoise, marine iguana, lava lizard, and other rare breeds.
As backwater a place as ever described in a Conrad novel, Dr. Koster's home is, he says, ''a paradise for biologists.'' The one-story station complex is a mile down a dirt road from the dusty little port town of Puerto Ayora on Academy Bay (named for the California Academy of Sciences, which led an expedition there in 1901). Here a couple of ramshackle hotels, some empty souvenir shops, and an unadorned restaurant with ceiling fans provide shelter from the equatorial heat for tourists. Colorful bougainvillea and leafy greenery, unusual for desert islands, indicate springs of fresh water on Santa Cruz.
Dressed in shorts and T-shirt, the tall, blond administrator talked about the international research facility. It was founded by a Belgian in 1960. Here scientists are trying to undo damage wrought by 17th--and 18th-century pirates, whalers, sealers, and salt miners. Thousands of tortoises were killed for their meat. Native fauna are still threatened by wild pigs, dogs, goats, and donkeys brought as domestic animals by the early seamen.
Dr. Koster explains: ''We have a scientist who researches only these feral animals, seeking ways to control their multiplication. Currently, we have a program to eradicate dogs and goats (already eliminated from one island); pigs and rats are next on the agenda. To ensure tortoise survival, we breed them in captivity, and, when old enough, put them back into their environment.''
At the station, tourists can visit the newly hatched tortoises and their elders. Another current project is a bird monitoring program to check declining flamingo, mockingbird, and Hawaiian petrel (almost extinct in Hawaii) populations. The Darwin Station works closely with the National Park to accomplish these goals.
Decidedly optimistic about the sanctuary's future, Dr. Koster explains: ''We get a filtered tourism: those who come to see penguins and sea lions, to find a sort of paradise like these forlorn islands untouched by the mark of man. A beach resort would just not fit here. (From June to December, the cold Humboldt current makes the water comfortable only for Galapagos penguins.) Even if there were unlimited tourism, I feel the number would not change.''
Indeed, the islands do seem fascinating, but hardly inviting to the sybaritic or the timid. For others, the Galapagos offer a kind of adventure. One can walk gingerly over lava rock to see blue-footed boobies nesting inches off the trail; ride in a dinghy along sheer cliffs to find penguins standing on the rocks of the equator as if it were Antarctica; be patiently quiet while a sea turtle creeps out of the ocean onto the beach, home to nest after years at sea. A sea lion may materialize in front of your snorkel mask. A mockingbird may alight on your hat. Perhaps you might even find yourself peering at little black birds, as common as sparrows, to see the size of their beaks--just because they are Darwin's finches.