Biology 54 Exam

_________________________________ _____________________ ________

Name Student Number Seat #

BIOLOGY 54 FINAL EXAM DECEMBER 14, 1996

Show all work for your calculations. Pace yourself. You have 3 hours.

1. Ecosystem Concepts (10 points)

All ecosystems must be able to conduct three basic functions. These are:

a.__________________________________

b.__________________________________

c.__________________________________ (3 points)

d. One mechanism is involved with two of these functions.

It is _____________________(1).

e. Define and explain the microbial loop. _______________________________________

___________________________________________________________________________

___________________________________________________________________________(3).

f. Name two ecosystems in which most (>50%) of the materials are processed in

the microbial loop. Explain your choices.

___________________________________________________________________________

___________________________________________________________________________(3).

2. Productivity (5 points)

a. Define and explain net primary productivity. (2 points)

___________________________________________________________________________

b. Rainforests have the world's highest gross primary productivity.

What is their net community productivity? _____________ (1 point)

Why?________________________________________________________________________

_____________________________________________________________________ (2 points)

3. Association Analysis and Data Interpretation (10 points total)

You have taken 100 benthic sediment samples in New Hope Creek, N.C.

The samples were from a range of particle sizes: cobbles, gravel and sand.

Stenocron interpunctatum, a small mayfly grazer, and Ephemerella dorothea

were found together in 48 samples and found missing entirely from 24 samples.

In 20 samples S. interpunctatum was absent and E. dorothea was present,

and in 8 samples E. dorothea was absent and S. interpunctatum was present.

Further analysis revealed that all these last 8 samples were from sandy

sediments. All the remaining samples were from gravel or cobbles. Analyze

these data.

a. Calculate the Test of Association for this study and state whether or not

it is significant. (Hint: The critical value for Chi square with degrees of

freedom = 1, p< 0.05 is 3.84).

X²= _________________ (2 points)

b. What is the value of the strength of association (V)?

V= _________________ (2 points)

c. Give two alternative explanations for these data (i.e. explain the

pattern of association of these two species).(4 pts.)

_____________________________________________________________________________

d. What should the next research step be, to follow up on this survey? (2 points)

__________________________________________________________________________________________________________________________________________________________

4. In your Duke Forest sampling you found the following species in the

given abundances. (10 points)

SPECIES ABUNDANCE

Quercus alba (White oak)...................45

Quercus rubrum(Red oak) .................22

Carya glabra(Pignut hickory).............20

Carya ovata(Shagbark hickory)..........12

Cornus florida(Dogwood) ..................25

Liriodendron tulipifera (Tulip poplar)..8

What is the species richness? (1 point)________________

What is the species diversity? (2 points)_______________

What is the evenness of species distributions? (2 points) ________________

What is the value of e^H'? (1 points)______________

What does this value (e^H') mean? (2 points)___________________________________________

_____________________________________________________________________________

What biome is this sample from and where else in the world will you

commonly find it?. (2 points)

Biome Name_______________________

Other global locations of this biome_________________________________________________

_____________________________________________________________________________

5. Disturbance (10 points)

Hurricane Fran was a classic local example of a disturbance. From it we

can deduce some general characteristics of disturbances.

a. Was the forest ecosystem adapted to this event?_____________ (1 point)

b. Was it predictable? Explain. _______________________________________

_______________________________________________________________(2 points)

c. What was the direct effect on the populations of white oak (Quercus alba)

and Loblolly Pine (Pinus taeda)?

_________________________________________________________________________

_________________________________________________________________(2 points)

d. What indirect effects will there be on tree seedlings, herbaceous plants

and other trees. Explain your answer.

_________________________________________________________________________

_________________________________________________________________(2 points)

e. Draw and interpret the graph of the Intermediate Disturbance Hypothesis.

Label all axes. Place an "dot" along the x-axis where you think Hurricane

Fran fits on the graph. (3 points)

______________________________________________________________________________

__________________________________________________________________________________________________________

6. Diversity has great value in natural systems. For each of the

following concepts explain how these various types of diversity are important

to each concept (5 points each, 20 points total)

A. Genetic drift and diversity

___________________________________________________________________________

B. Genetic diversity and improvement of fitness of a population.

___________________________________________________________________________

C. Diversity of diet and species packing

___________________________________________________________________________

D. Biodiversity and stability of ecosystem processes

___________________________________________________________________________

7. Spatial heterogeneity is an important factor in ecological processes

at all levels of organization. Explain how heterogeneity works to influence

the outcome of the following situations. Illustrations may be helpful in

your answers. (5 points each, 15 points total)

A. Stabilizing predator prey relationships

___________________________________________________________________________

B. Coexistence of similar species.

___________________________________________________________________________

C. Variation in rates of ecosystem processes

___________________________________________________________________________

8. Many species are highly specialized. Give all the steps necessary to

evolve a brown bat (an efficient flying mammal with echo-location sonar to

capture prey) from a generalized mammal. Be sure to include the source

of genetic variation, how that variation is maintained, and the ecological

processes involved in differentiation and speciation. Give up to ten steps..

Think about speciation processes in general and this bat in particular.

(10 points).

STEPS:

1.________________________________________________________________

2.________________________________________________________________

3.________________________________________________________________

4.________________________________________________________________

5.________________________________________________________________

6.________________________________________________________________

7.________________________________________________________________

8.________________________________________________________________

9.________________________________________________________________

10.________________________________________________________________

9. Matching (10 points)

Enter the letter describing the research idea or accomplishment associated

with the Scientist in the space beside the name. There are at least 20 correct

answers. Each is worth 1/2 point. Each incorrect answer will cost you 1/4 point.

Do not guess!

1. Whittaker____________ a. Competition

2. MacArthur____________ b. Keystone predation

3. Volterra_______________ c. Limiting Similarity

4. Huffaker_____________ d. Niche theory

5. Hutchinson________________ e. Spatial heterogeneity

6. Gause________________ f. Continuum of species in communities

7. Paine________________ g. Diversity

8. Connell _____________ h. Population growth

9. Darwin_______________ I. Succession

10. Keever _____________ j. Community Structure

Honor Code Pledge________________________________________________

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Signature_________________________________