大学英语6级考试模拟试卷一

less, soft-bodied creatures were suddenly replaced by trilobites（三叶虫）, then by the more advanced clam-like animals. These changes, he notes, “first become common near shore.” That surprised him—an environment with as few species as exist in the near shore, and with such a poor record of producing new species, seems an unlikely place for biological innovation. But when Jablonski dated fossils of 100 million years ago, he found that during this era, too, the near shore spawned biological breakthroughs—more sophisticated sea creatures that move and find food in ocean sediments instead of passively filtering whatever floats by.

The findings are too new to apply to human evolution, but at first glance they seem to fit the facts. Anthropologists believe that our ancestors became fully human only after they left their secure life in the trees for the harsh world of savanna(plain without trees). There, the demanding conditions triggered that most human of traits, the large brain, and the most profound evolutionary step of all was taken.

26. Two recent papers in Science magazine claim to have found evidence which contradicts the traditional notion that          .

A) relatively harsh environments are the nurseries of evolution

B) evolution occurred in regions with biological diversity

C) new forms of life come into being in near-shore areas

D) species of birch and redwood originated in the south

27. According to Leo Hickey of Yale University, which of the following may have spawned more advanced species of land animals?

A) The barren ocean floor.B) The Arctic.

C) The rain forest.D) Temperate Zones.

28. The word “innovations” in the second paragraph means          .

A) new theoryB) new phenomenonC) changesD) new inventions

29. How would anthropologists take the new findings?

A) They would look at them dubiously.