What does it mean to say that we are "fishing down the food chain"?
What will be an ideal response?
Sizes of caught fish decline with higher rates of fishing. As we overfish the seas, we have largely eliminated stocks of large predators, many of whom are adult commercial fish species and are keystone species. Now we are fishing our way through more moderately sized consumers. Because food chains are not infinitely long, we will eventually be left with only primary consumers, which may not be very palatable. The removal of keystone species from any food has cascade effects that can produce serious and far-reaching disruptions. These include the possibility of allowing other species to replace the decimated fish species as new top consumers.
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Which of these is a vector quantity?
A. Velocity. B. Acceleration. C. Force. D. all of the above
Which of the following best matches the description?Chemical produced by one animal that changes the behavior of another.
A. micronutrients B. micronutrient C. macronutrients D. chlorinated hydrocarbon E. fungicide F. pheromone G. persistent pesticide H. hard pesticide I. auxin J. biomagnification K. herbicide L. weed M. organophosphate N. biocide O. rodenticide P. soft pesticide Q. macronutrient
Which of the following geologic resources was discussed for the area around St. George, Utah?
A. a large cement plant B. an oil field and floodplains with fertile soils C. floodplains with fertile soils D. oil field E. All of these choices are correct.
As Earth revolves around the Sun, Earth's axis remains parallel to its former positions. What is this characteristic called?
a. repeated inclination b. parallelism c. true bearing d. angle of incidence e. ecliptic