Plant Ecology 03-55-468 - University of Windsor



Equations you may need for the midterm exam:

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GRR = ( mx

r = ln(R0)/G

VP = VG + VE + covGE

VP = VA + VD + VI + VE + VGxE + covGE

VA/VP = h2

R = Sh2

Plant Ecology 03-55-468

Midterm Exam

November 2, 2011

Match the following terms from the left hand column with the appropriate definition from the right hand column. Enter the letter of the definition in the blank. Only one definition is correct; more definitions are provided than terms. (1 mark each)

1._m___ vessel elements

2._j___ water use efficiency

3._a___ reaction norm

4._d___ pericycle

5._r___ stroma

6._l___ light compensation point

7._o___ reproductive value

8._g___ breeding value

9._k___ nitrogen use efficiency

10._p__ activity limit

11._q__ tracheid

12._h__ eluvation

13._i__ elasticity

14._f__ latent heat exchange

15._s__ phenotypic plasticity

16._c__ podzol (spodisol)

17._n__ stolons

18._e__ apoplast

a. the way in which a quantitative trait responds to a range of environmental conditions

b. the soil type found in prairie grassland and steppe regions

c. the soil type found in boreal forest regions

d. the outer layer of the stele in roots of dicots; it is meristematic tissue that can give rise to root branches

e. the tissue fluid bathing cells

f. the loss of heat energy from a leaf due to evaporation and transpiration

g. the deviation of the phenotypic value of an individual’s progeny from the population mean

h. the percolation of soluble minerals and fine particles down from upper soil horizons to lower in the soil profile

i. the relative impact of elements in a Leslie or Lefkovich matrix on the finite rate of increase

j. the number of grams of carbon fixed in photosynthesis per gram of water lost to transpiration

k.the maximum photosynthetic rate per gram of nitrogen in a leaf

l. a light intensity at which the rate of photosynthesis and the rate of photorespiration are equal

m. short, wide conducting elements in the xylem of Angiosperms only

n. above ground, spreading root branches from which new ramets may arise

o. the contribution in offspring that an average individual in stage x will make to the next generation before it dies

p. the temperatures (high or low) at which a plant ceases to function effectively

q.a type of elongated cell that forms the water conducting tissue in primitive vascular plants

r. the watery matrix that fills the chloroplasts

s. none of the above are correct

Circle the correct answer for each of the following multiple choice questions (1 mark each)

19. Which of the following is a plant that uses CAM (Crassulacean Acid Metabolism)?

a. a prairie grass like Andropogon gerardii

b. an red oak tree, Quercus rubra

c. a boreal forest tree, Populus tremuloides

d. an epiphytic Spanish moss, Tillandsia

usneoides

20. In which of these environments would you be most likely to find a C4 plant?

a. a low arctic meadow

b. a high mountain grassland

c. a prairie grassland in the central U.S.

d. in a local deciduous forest

21. Where is PEP carboxylase found within a plant leaf?

a. in the bundle sheath

b. within the chloroplasts

c. in the cells of the xylem

d. in the mesophyll cells

22. How do you prove a hypothesis?

a. by performing an experiment and finding results consistent with the hypothesis

b. by performing a series of experiments and finding the results of each consistent with the hypothesis

c. by finding results in the literature consistent with the hypothesis

d. you cannot prove the hypothesis

23. Which of the following is not a common function of the mycorrhizae associated with plant roots?

a. to provide the plant with certain soil nutrients

b. to provide the plant with carbohydrates as an

energy source

c. to facilitate the absorption of soil water

d. to excrete organic acids that help to solubilize

some minerals in the soil

24. Photorespiration:

a. occurs in C3, but not in C4 plants

b. occurs in C4, but not in C3 plants

c. releases free oxygen as a waste product

d. involves activities only in the chloroplasts

25. Cyclic photophosphorylation occurs:

a. in photosystem I only

b. in photosystem II only

c. in both photosystems I and II

d. in neither photosystem

26. Rubisco (ribulose biphosphate carboxylase) occurs in:

a. C3 plants only

b. C4 plants only

c. CAM plants only

d. C3 and C4 plants

e. all photosynthetic plants

27. The A horizon of the soil:

a. consists of litter and partially decomposed

plant materials from previous years’ growth

b. is a layer comprised of decomposed and

decomposing plant materials mixed with

surface soil

c. is the layer into which minerals and water are

leached from above

d. is the original parent material from which soil

is formed

28. Which of the following correctly defines the gross reproductive rate?

a. the total number of female offspring born to

an average female in the population

b. the total number of female offspring born

to a mother who lives to the maximum age

in the population

c. the number of female offspring born to an

average female in her year of peak

reproductive output

29. In the Krantz anatomy of C4 plants, where is

rubisco found?

a. in the mesophyll cells

b. in the bundle sheath cells

c. in the vessel element cells

d. there is no rubisco in C4 plants

30. In which of the following is the number and density of chloroplasts lowest?

a. in the mesophyll of C3 plant leaves

b. in the bundle sheath of C3 plant leaves

c. in the mesophyll of C4 plant leaves

d. in the bundle sheath of C4 plant leaves

31. In C4 plants where is the oxygen concentration highest?

a. in the chloroplasts of mesophyll cells

b. in the chloroplasts of bundle sheath cells

c. in the vessel element cells

d. in the tissues of the roots

32. In C4 photosynthesis, what is the initial molecule formed as the result of carbon fixation?

a. a short-lived 6 carbon molecule

b. PEP (phosphoenolpyruvate)

c. a 4-carbon molecule, oxaloacetate

d. ribulose biphosphate

29. Here is some data about flower size in a new strain of roses:

Mean diameter of flowers on maternal parents 45mm

Mean diameter of flowers on maternal parents selected for size 60mm

Mean diameter of flowers for all progeny plants 50mm

Mean diameter of flowers on progeny of selected female parents 58mm

What is the heritability of flower size in this population of roses? (10)

Selection difference = 60-45 = 15

Response difference = 58-50 = 8

R = Sh2

8 = 15h2

h2 = 8/15 = .533

30. Below is a Lefkovitch matrix for the transition probabilities in a fictional population of a weed that shows size dependent flowering and reproduction. A basic set of boxes representing the stages for this species is presented below the matrix. Add to the diagram arrows and numbers corresponding to processes indicated in the matrix. (10)

0 .01 .001 300

.3 .47 .05 0

.02 .61 .82 0

0 0 .129 0

300

.001

.01

.05

0 .47 .82

.3 .61 .129

.02

31. Briefly describe an experimental design that would test whether observed phenotypic variation in the “red-flowered witch weed” [my made-up plant] observed over a range from Ontario to Alberta is genetic in origin or is the result of phenotypic plasticity. (10)

The experiment would take the form of a “common garden” growth experiment or a reciprocal transplant experiment. In the former, plants from Ontario, Manitoba, Saskatchewan and Alberta would all be moved (probably by planting seeds from all sources) in a common location. Plant growth and phenotypic characteristics would be followed for all. To the degree they all look similar in the “common garden” the previously observed variation resulted from phenotypic plasticity.

If you choose to do a reciprocal transplant experiment, plants from each location would be dug up and some replanted in situ; others would be moved and planted in each of the other sites. To make sure soil differences are not responsible for observed characteristics, the roots of each re-plant should be carefully washed just before re-planting. The further growth and phenotypes would be monitored in each site. Phenotypic plasticity would be indicated by the growth and character of transplants coming to resemble plants originally from the re-planting site.

29a.Every process that affects gene frequencies also affects genetic diversity in plant populations. Consider a small isolated population, a population of compass plant in a small prairie remnant. For each of the four processes considered in determining whether a population is in Hardy-Weinberg equilibrium indicate whether the process increases or decreases the genetic diversity of this isolated population. (10)

This question is concerned only with within population genetic diversity.

Mutation – should increase the genetic diversity within an isolated population.

Gene flow/migration – should increase the genetic diversity within the isolate.

Genetic drift – should decrease the genetic diversity within the isolate.

Natural selection should also decrease the genetic diversity in the isolate.

b. For each of those processes briefly describe the mechanism by which the genetic diversity is enhanced or decreased. (10)

Mutation introduces new forms of alleles into individuals who suffer the mutations. The population thus increases in allelic diversity, though some of the mutated alleles may be detrimental.

Gene flow brings alleles from other populations. Since this is a small, isolated population of compass plant, before gene flow its genetic diversity probably incorporates only a fraction of the total genetic diversity of compass plants in other remnants and larger prairie areas. Gene flow will carry some of those unrepresented alleles into this remnant population and thus increase genetic diversity within it.

Genetic drift in small populations results in the loss of genes carried in those individuals who die prematurely or fail to successfully reproduce. Some of those individuals will have carried rare alleles, and the loss of the individual means the loss of those alleles, thus a decrease in genetic diversity.

Natural selection, by leading to the death or reduced representation of offspring in future generations, reduces the representation of genes carried by individuals selected against, and thus reduces genetic diversity in the isolated population.

31. Here is the life table you expected. Calculate R0 (4), G (4), and r (4). Project the population numbers given for time 0 (i.e. N0) for one time period (10). Show your work (including any intermediate calculations) so that partial credit can be given when simple math errors result in incorrect answers. (22 total)

age N0 lx mx lxmx xlxmx px Fx N1

0 100 1 0 0 0 .7 0 199.5+281.25+20=500.75

1 700 .7 .5 .35 .35 .57 .285 70

2 300 .4 1.5 .6 1.2 .625 .9375 399

3 50 .25 1 .25 .75 .4 .4 187.5

4 25 .1 .5 .05 .2 0 0 20

5 0 0 0 0 ___

R0 = ( = 1.25 2.5

G = ( xlxmx/R0 = 2.0

r = ln R0/G = ln 1.25/2.0 = .223/2 = .111

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