1. Plant Diversity II: The Evolution of Seed Plants
Plant Diversity II: The Evolution of Seed Plants

2. The reason that two sperm nuclei travel down the pollen tube is that
they both stimulate growth of the pollen tube.
one fertilizes the egg, and the other combines with the two polar nuclei.
one fertilizes the egg, and the other fertilizes the synergid.
one is for fertilizing the egg, and one directs the pollen tube toward the micropyle.
if one fails in fertilization, there is a backup nucleus.
Answer: b

3. The reason that two sperm nuclei travel down the pollen tube is that
they both stimulate growth of the pollen tube.
one fertilizes the egg, and the other combines with the two polar nuclei.
one fertilizes the egg, and the other fertilizes the synergid.
one is for fertilizing the egg, and one directs the pollen tube toward the micropyle.
if one fails in fertilization, there is a backup nucleus.

4. Adaptations that have contributed to the success of plants in terrestrial environments include seeds, vascular tissue, cuticle, and flowers. There are other significant adaptations as well. Which of the following correctly lists the adaptations in the order in which they appeared in the fossil record?
seeds, vascular tissue, flowers, cuticle
cuticle, seeds, flowers, vascular tissue
cuticle, vascular tissue, seeds, flowers
vascular tissue, cuticle, seeds, flowers
Answer: c

5. Adaptations that have contributed to the success of plants in terrestrial environments include seeds, vascular tissue, cuticle, and flowers. There are other significant adaptations as well. Which of the following correctly lists the adaptations in the order in which they appeared in the fossil record?
seeds, vascular tissue, flowers, cuticle
cuticle, seeds, flowers, vascular tissue
cuticle, vascular tissue, seeds, flowers
vascular tissue, cuticle, seeds, flowers

6. These four adaptations (cuticle, vascular tissue, seeds, and flowers) are key characters that define four major modern plant groups. Complete the following table using the key provided.
a) ferns (and relatives) b) bryophytes (mosses) c) flowering plants d) gymnosperms
Answer: a

7. These four adaptations (cuticle, vascular tissue, seeds, and flowers) are key characters that define four major modern plant groups. Complete the following table using the key provided.
a) ferns (and relatives) b) bryophytes (mosses) c) flowering plants d) gymnosperms

8. These four adaptations (cuticle, vascular tissue, seeds, and flowers) are key characters that define four major modern plant groups. Complete the following table using the key provided.
a) ferns (and relatives) b) bryophytes (mosses) c) flowering plants d) gymnosperms
Answer: d

9. These four adaptations (cuticle, vascular tissue, seeds, and flowers) are key characters that define four major modern plant groups. Complete the following table using the key provided.
a) ferns (and relatives) b) bryophytes (mosses) c) flowering plants d) gymnosperms

10. The reason that two sperm nuclei travel down the pollen tube is that
they both stimulate growth of the pollen tube.
one fertilizes the egg, and the other combines with the two polar nuclei.
one fertilizes the egg, and the other fertilizes the synergid.
one is for fertilizing the egg, and one directs the pollen tube toward the micropyle.
if one fails in fertilization, there is a backup nucleus.
Answer: b 10

11. The reason that two sperm nuclei travel down the pollen tube is that
they both stimulate growth of the pollen tube.
one fertilizes the egg, and the other combines with the two polar nuclei.
one fertilizes the egg, and the other fertilizes the synergid.
one is for fertilizing the egg, and one directs the pollen tube toward the micropyle.
if one fails in fertilization, there is a backup nucleus. 11

12. In dicotyledon seed germination, usually the first organ to emerge from the seed is the
shoot tip, as the most important function to get under way is breaking through the soil.
hypocotyl, as the most important function to get under way is breaking through the soil.
cotyledon(s), as the most important function to get under way is photosynthesis.
radicle, as the most important function to get under way is the absorption of water and nutrients.
root, as the most important function to get under way is the anchoring of the plant to the soil.
Answer: d 12

13. In dicotyledon seed germination, usually the first organ to emerge from the seed is the
shoot tip, as the most important function to get under way is breaking through the soil.
hypocotyl, as the most important function to get under way is breaking through the soil.
cotyledon(s), as the most important function to get under way is photosynthesis.
radicle, as the most important function to get under way is the absorption of water and nutrients.
root, as the most important function to get under way is the anchoring of the plant to the soil. 13

14. All of the following statements regarding double fertilization in the angiosperms is true except which one?
The angiosperm embryo is diploid.
The pollen tube reaching the micropyle results in the death of one of the synergids.
The fertilized angiosperm ovule consists of diploid and triploid cells.
The megasporangium gives rise to four haploid eggs through meiosis.
One of the pollen nuclei contributes to the genome of the endosperm.
Answer: d 14

15. All of the following statements regarding double fertilization in the angiosperms is true except which one?
The angiosperm embryo is diploid.
The pollen tube reaching the micropyle results in the death of one of the synergids.
The fertilized angiosperm ovule consists of diploid and triploid cells.
The megasporangium gives rise to four haploid eggs through meiosis.
One of the pollen nuclei contributes to the genome of the endosperm. 15

16. The flowers of wind-pollinated plants
usually have flat blades to direct the wind.
produce sticky pollen.
are usually green and inconspicuous.
are usually white and small.
usually occur on separate male and female plants.
Answer: c 16

17. The flowers of wind-pollinated plants
usually have flat blades to direct the wind.
produce sticky pollen.
are usually green and inconspicuous.
are usually white and small.
usually occur on separate male and female plants. 17

18. An accessory fruit is one that
grows from a lateral meristem.
develops from tissue other than the ovary.
develops from the pericarp.
consists of multiple receptacles.
is not necessary for reproduction.
Answer: b 18

19. An accessory fruit is one that
grows from a lateral meristem.
develops from tissue other than the ovary.
develops from the pericarp.
consists of multiple receptacles.
is not necessary for reproduction. 19

20. Which of the following lists an aggregate fruit, a multiple fruit, and an accessory fruit, in that order?
guava, blackberry, cherry
watermelon, orange, fig
apple, pear, cherry
pineapple, tangerine, cranberry
strawberry, fig, pear
Answer: e 20

21. Which of the following lists an aggregate fruit, a multiple fruit, and an accessory fruit, in that order?
guava, blackberry, cherry
watermelon, orange, fig
apple, pear, cherry
pineapple, tangerine, cranberry
strawberry, fig, pear 21

22. Scientific Skills Exercises
One unusual opportunity to test how long seeds can remain viable occurred when seeds from date palm trees (Phoenix dactylifera) were discovered under the rubble of a 2,000-year-old fortress near the Dead Sea. Scientists measured the fraction of carbon-14 that remained in three of the ancient date palm seeds: two that were not planted and one that was planted and germinated. (For the germinated seed, the scientists used a seed-coat fragment found clinging to a root of the seedling.) The table shows their results.
Data from S. Sallon, et al., Germination, genetics, and growth of an ancient date seed. Science 320:1464 (2008).

23. An ancient date palm seed germinated and grew into a healthy plant
An ancient date palm seed germinated and grew into a healthy plant. What was the source of nutrients for the young sporophyte embryo during germination of the date palm seed?
a) sunlight
b) food stored within the seed
c) water taken up by the germinating seed
d) the surrounding soil
Answer: b

24. An ancient date palm seed germinated and grew into a healthy plant
An ancient date palm seed germinated and grew into a healthy plant. What was the source of nutrients for the young sporophyte embryo during germination of the date palm seed?
a) sunlight
b) food stored within the seed
c) water taken up by the germinating seed
d) the surrounding soil

25. Why is seed dormancy adaptive for many plant species?
a) Seed dormancy increases the longevity of an individual sporophyte plant.
b) Seed dormancy allows seeds to germinate when conditions are favorable for seedling growth.
c) Seed dormancy ensures that a seedling does not compete with its parents.
d) Seed dormancy ensures that a seedling does not germinate when a source of food is not available for the young seedling.
Answer: b

26. Why is seed dormancy adaptive for many plant species?
a) Seed dormancy increases the longevity of an individual sporophyte plant.
b) Seed dormancy allows seeds to germinate when conditions are favorable for seedling growth.
c) Seed dormancy ensures that a seedling does not compete with its parents.
d) Seed dormancy ensures that a seedling does not germinate when a source of food is not available for the young seedling.

27. A logarithm is the power to which a base is raised to produce a given number x. For example, if the base is 10 and x = 100, the logarithm of 100 equals 2 (because 102 = 100). A natural logarithm (ln) is the logarithm of a number x to the base e, where e is about Natural logarithms are useful in calculating rates of some natural processes, such as radioactive decay.
The equation F = e–kt describes the fraction F of an original isotope remaining after a period of t years; the exponent is negative because it refers to a decrease over time. The constant k provides a measure of how rapidly the original isotope decays. For the decay of carbon-14 to nitrogen-14, k =

28. You can rearrange this equation to solve for t by following these steps:
Take the natural logarithm of both sides of the equation ln(F) = ln(e–kt ). Rewrite the right side of this equation by applying the following rule: ln(ex) = x ln(e).
2. Since ln(e) = 1, simplify the equation.
3. Now solve for t in the form “t = ____.”

29. Which equation correctly solves for t?
t = ln(F) − k ∗ ln(e)
t = ln(F) − k
c) t = ln(F)ln(e − k)
d) t = log10(F) − k
Answer: b

30. Which equation correctly solves for t?
a) t = ln(F) − k ∗ ln(e)
b) t = ln(F) − k
c) t = ln(F)ln(e − k)
d) t = log10(F) − k