3.4.97
bio2.html
Agronomy 317: Quiz 6
Biology & Ecology
March 3, 1997
Instructions:
1. Return your answers to each of the questions below to me before March
17. Write your answers on a separate page. When you are done, check them
carefully and then Email me your answers to:
<jdekker@iastate.edu>
2. This is an "open book" exam. This means you can use any source
of information except another person. This exam is done on the honor system.
3. Your exam grade will be sent to you after March 17.
4. There are 30 questions, each worth one point, 30 points total for the
quiz.
5. Provide the BEST answer.
Good Luck
1. What are the two types of weed mortality? Provide an example for
each
2. What animal has been responsible for the most seed dispersal between
continents?
3. List 3 things farmers do that could result in weed population shifts
in their fields.
4. What is the most common type of dispersal mechanism found with weed
species?
5. List 5 reasons why velvetleaf is so well adapted as a weed in agricultural
habitats?
6. What is your "favorite" weed species? Why?
7. Define dormancy.
8. During the spring and summer when foxtail plants emerge, what is
the single most important thing determining the success of an individual
foxtail plant (non-herbicide)?
9. Are Iowa seedbanks larger or smaller today than they were in 1797?
Why?
10. Define adaptation.
11. Why does common cocklebur have barbed hooks on its seed capsule?
12. What long term effects did 2,4-D have in Iowa corn fields after
the herbicide was introduced in the 1940's
13. What are the 4 dimensions seed can be dispersed in? Give examples
for 2 of them.
14. List 3 important ways seed are lost from the soil seedbank.
15. Define plasticity. Provide an example of plasticity in crop-weed
competition.
16. Describe the sizes (and abundances of each size) of weed plants
comprising a population at harvest time if little or no weed control was
used in the crop field.
17. What is a "safe-site" for a seed in the spring?
18. List 4 reasons why the foxtails are so well adapted as a weeds
in agricultural habitats?
19. What did you find most interesting in the Weedy Adaptation section?
Explain why you found it interesting.
20. What is the longest known time period a common lambsquarter plant
has survived in the soil seedbank?
21. Provide an example of somatic polymorphism in seed dormancy.
22. List 5 limited resources plants compete for in crop fields.
23. What are the 5 roles of a seed?
24. What did you find most interesting in The Seed section? Explain
why you found it interesting.
25. Are Iowa seedbanks deeper or shallower today than they were in
1797? Why?
26. List 4 weed species we have studied that disperse their seeds with
the help of wind.
27. Why did all the common cocklebur seed end up at the high water
mark in the corn field after the flooding.
28. In what form does common lambsquarters exist the longest in its
life cycle?
29. List 3 reasons why quackgrass is so well adapted as a weed in agricultural
habitats?
30. What did you find most interesting in the The Plant section? Explain
why you found it interesting.
©jdekker-1997