2014 AP Biology

Exam FRQ.

I have 3 free response questions from the 2014 AP Bio exam. The questions
and

Question

2014 AP Biology Exam FRQ.

I have 3 free response questions from the 2014 AP Bio exam. The questions and

requirements are in the pdf document, it also contain grading guidelines and answers, and student’s sample answer.

I really need help to put it in my own words and thoughts and not just copy the student sample answer.
See ap14_biology_q1.pdfAP® BIOLOGY
2014 SCORING GUIDELINES
Question 1
Trichomes are hairlike outgrowths of the epidermis of plants that are thought to provide protection against
being eaten by herbivores (herbivory). In a certain plant species, stem trichome density is genetically
determined.
To investigate variation in stem trichome density within the plant species, a student counted the number
of trichomes on the stems of six plants in each of three different populations. The student used the data to
calculate the mean trichome density (numbers of hairs per square centimeter) for each population. The
resus are provided in the table below.
TRICHOME DENSITY IN THREE PLANT POPULATIONS (number of trichomes/cm2)
Population Plant 1 Plant 2 Plant 3 Plant 4 Plant 5 Plant 6 Sample
Mean Standard
Error of the
Mean (SEM)
1 I 8 11 9 10 8 6 9 II 12 6 15 9 13 8 11 1 III 13 17 9 14 12 16 14 1 (a) On the axes provided, create an appropriately labeled graph to illustrate the sample means of the three
populations to within 95 percent confidence (i.e., sample mean ± 2 SEM). (3 points maximum; LO 1.1)
• Correctly labeled, scaled, with proper units
• Bar graph or modified bar graph with appropriately plotted means
• 2x standard error (SEM) above and below means
(b) Based on the sample means and standard errors of the means, identify the two populations that are
most likely to have statistically significant differences in the mean stem trichome densities. Justify
your response. (2 points maximum; LO 4.11, 4.19)
Identification (1 point)
• Populations I and III
Justification (1 point)
• The error bars/95 percent confidence intervals for populations I and III do not overlap
• (Sample mean + 2 SEM of population I) ; (Sample mean − 2 SEM of population III) © 2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. AP® BIOLOGY
2014 SCORING GUIDELINES
Question 1 (continued)
(c) Describe the independent and dependent variables and a control treatment for an experiment to test
the hypothesis that higher trichome density in plants is selected for in the presence of herbivores. Also
identify an appropriate duration of the experiment to ensure that natural selection is measured and
predict the experimental resus that would support the hypothesis. (5 points maximum; LO 1.5, 1.11)
NOTE: Points are earned in a single row only.
Independent
Dependent
Control
Variable
Variable
(1 point)
(1 point)
(1 point) Duration
(1 point) Presence of
herbivores Trichome density Absence of
herbivores More than one
generation Trichome
density in the
presence of
herbivores Reproductive
success OR
# of plants Plants with lower
trichome density More than one
generation © 2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. Prediction
(1 point)
Increased trichome
density relative to
control
Size of the population
with higher trichome
density will be larger
than control population ©2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. ©2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. ©2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. ©2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. ©2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org. ©2014 The College Board.
Visit the College Board on the Web: www.collegeboard.org.

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