Both tropical and temperate, the Galapagos Islands are volcanic; therefore, all species that now inhabit them arrived by sea and by wind, including those that arrived by human means of dispersal. Due to the unique and remote location of the archipelago, some species, such as reptiles, were able to survive and thrive, while other species and groups, such as amphibians and mammals, are scarcely in evidence in the island chain. Thriving groups have produced species that are endemic to the archipelago: some 86% of its reptiles live nowhere else. Since the arrival of Darwin, blown by the wind and carried by the sea, the island group has been prized as a seedbed and mecca of genetic diversity, a natural laboratory of species adaptation and evolution. Because of the distance of some 600 miles from the mainland, the original arrival of species, some by means of floating on a raft of algae, others by means of an against-all-odds long-distance swim, may seem a form of travail and triumph for some species. But today, the 600-mile distance seems far smaller as environmentalists worry about the invasive species that threaten the islands. For example, tiny fire ants that arrived with humans threaten the hatchlings of tortoises and some birds.

1. Which of the following statements finds the LEAST support in the passage?

(A) Darwin’s arrival at the Galapagos Islands had at least something in common with original species arrival.
(B) The Galapagos island chain is a unique genetic environment for the study of species development.
(C) Some species endured harsh salt, sun, and waves over a long distance before arriving in the Galapagos.
(D) Human introduction of new species types has been injurious to island ecosystems.
(E) Two distinct climate types are responsible, in part, for the extraordinary genetic diversity in the Galapagos.


2. The author mentions the idea of endemic species in order to

(A) help show why the Galapagos islands are unique as a laboratory for the study of species evolution.
(B) explain further that endemic species are those that live only in the Galapagos archipelago.
(C) suggest the reason why Darwin chose to focus his studies on the animals of the island chain.
(D) examine the reasons why certain island conditions favored the adaptation of some species and not others.
(E) describe the evolutionary impact of certain species on the ever evolving ecology of the island chain.


3. Which of the following statements is most readily inferable from the information in the passage?

(A) The odds against survival on the islands were greatest for those life forms originating in temperate climates.
(B) Galapagos reptiles outcompeted and displaced original amphibian populations.
(C) When they rise from the sea, volcanic islands are completely devoid of life.
(D) The odds in favor of survival on the islands were greatest for those species that were able to swim to the archipelago.
(E) The 600-mile distance to the mainland continues to favor the arrival and survival of certain species.