Bundle: Biology: The Unity and Diversity of Life, Loose-leaf Version, 14th + LMS Integrated for MindTap Biology, 2 terms (12 months) Printed Access Card
Bundle: Biology: The Unity and Diversity of Life, Loose-leaf Version, 14th + LMS Integrated for MindTap Biology, 2 terms (12 months) Printed Access Card
14th Edition
ISBN: 9781305775480
Author: Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr
Publisher: Cengage Learning
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Chapter 6, Problem 2DAA

Energy Efficiency of Biofuel Production Most of the plant material currently used for biofuel production in the United States consists of food crops—mainly corn, soybeans, and sugarcane. In 2006, David Tilman and his colleagues published the results of a 10-year study comparing the net energy output of various biofuels. The researchers grew a mixture of native perennial grasses without irrigation, fertilizer, pesticides, or herbicides, in sandy soil that was so depleted by intensive agriculture that it had been abandoned. They measured the usable energy in biofuels made from the grasses, and also from com and soy, then measured the energy it took to grow and produce biofuel from each kind of crop (FIGURE 6.18).

Chapter 6, Problem 2DAA, Energy Efficiency of Biofuel Production Most of the plant material currently used for biofuel

FIGURE 6 .18 Energy inputs and outputs of biofuels made from three different crops. One hectare is about 2 .5 acres.

2. Which of the biofuels tested had the highest ratio of energy output to energy input?

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Use the following information to answer the question(s) below. Martin Wikelski and L. Michael Romero (Body size, performance and fitness in Galápagos marine iguanas, Integrative and Comparative Biology 43 [2003]:376-86) measured the snout-to-vent (anus) length of Galápagos marine iguanas and observed the percent survival of different-sized animals, all of the same age. The graph shows the log snout-vent length (SVL, a measure of overall body size) plotted against the percent survival of these different size classes for males and females. Survival (%) 100- 80- 60- 40- 20- 0+ 1.9 T 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Log SVL (mm) 19) Examine the figure above. What type of selection for body size appears to be occurring in these marine iguanas? A) directional selection B) stabilizing selection C) disruptive selection D) You cannot determine the type of selection from the above information. 3
24) Use the following information to answer the question below. Researchers studying a small milkweed population note that some plants produce a toxin and other plants do not. They identify the gene responsible for toxin production. The dominant allele (T) codes for an enzyme that makes the toxin, and the recessive allele (t) codes for a nonfunctional enzyme that cannot produce the toxin. Heterozygotes produce an intermediate amount of toxin. The genotypes of all individuals in the population are determined (see table) and used to determine the actual allele frequencies in the population. TT 0.49 Tt 0.42 tt 0.09 Refer to the table above. Is this population in Hardy-Weinberg equilibrium? A) Yes. C) No; there are more homozygotes than expected. B) No; there are more heterozygotes than expected. D) It is impossible to tell.
30) A B CDEFG Refer to the accompanying figure. Which of the following forms a monophyletic group? A) A, B, C, and D B) C and D C) D, E, and F D) E, F, and G
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