Discuss the reasons for the so-called “Cambrian Explosion.” What factors were important in this
change in apparent fossil populations? Give examples of some of the organisms that lived
during this time. What will be an ideal response?
The student should recognize that the Precambrian animals were soft-bodied and very difficult to
preserve as fossils. The development by organisms of hard parts facilitated their preservation as
fossils and provided a very different picture of ecosystems. However, there does appear to be a
proliferation of different animal phyla around the Precambrian-Cambrian boundary. This
proliferation is not fully understood.
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Why is the AIDS pandemic globally far reaching?
What will be an ideal response?
In humid regions of low relief, lakes can form _____
a. below a perched water table b. at cones of depression c. where infiltration to the subsurface is high d. at swallow holes e. where the water table intersects the ground surface
Why was the mid-continent earthquake story discussed in Chapter 1?
A. It illustrated the characteristics of good science. B. It illustrated characteristics of bad science. C. It illustrated the characteristics of the limitations of science.
The agricultural movement that has boosted yields by (1) developing high-yield varieties, (2) using large inputs of water and fertilizer, and (3) multiple cropping is called the ________ revolution.
Fill in the blank(s) with the appropriate word(s).