Question 1

In Utah there is a clone of aspen trees that covers over 100 acres. Such clones can be considered to be a single plant with many stems. It appears that the first stem of this clone originated over 80,000 years ago, even before there were humans in North America. What likely contributes most to the long-term survival (long life span) of aspens?

Accepted Answer

A shared root system allows aspen clones to survive damage to individual stems because other parts can continue growing, contributing significantly to their long-term survival.

Question 2

While cleaning out the attic, you find a packet of seeds that your grandmother gathered from her garden. You plant them outside, and some of them sprout. What was the condition of these germinating seeds while they were in the attic?

Accepted Answer

Seeds can be in a state of dormancy where they are alive but in an inactive state until conditions are favorable for germination. The seeds found in the attic were likely in a state of dormancy until they were planted and received water, which promoted germination.

Question 3

How many chromosomes are there in a maize (corn) embryo cell nucleus as compared to a maize (corn) endosperm cell nucleus?

Accepted Answer

A maize embryo cell is diploid with 20 chromosomes, while the endosperm is triploid with 30 chromosomes, making the embryo have two-thirds the number of chromosomes as the endosperm.

Question 4

What is a disadvantage of cloning as a propagation technique?

Accepted Answer

Cloning produces genetically identical plants, meaning they have the same susceptibility to diseases and pests. If a disease or pest affects one plant, it can quickly spread to the entire population of cloned plants. This can potentially wipe out an entire crop and is a significant disadvantage of cloning as a propagation technique.

Question 5

What is a function of a fruit?

Accepted Answer

The function of a fruit is to aid in seed dispersal, which is option C. Fruits are an adaptation in plants that contain seeds. They develop from the ovary after pollination and fertilization, and protect the seeds inside until they are ready to be dispersed. Fruits can be eaten by animals, and the seeds pass through their digestive system, helping to disperse the seeds at a distance from the parent plant.

Question 6

In which situation would plant reproduction most likely be pollinator-limited?

Accepted Answer

In a very large field of a single crop covering a large area, the monoculture can lead to a lack of diversity in pollinators, making plant reproduction more likely to be pollinator-limited.

Question 7

Which structure is the first to emerge from the germinating seed of a eudicot such as the garden bean?

Accepted Answer

The embryonic root, also known as the radicle, is the first structure to emerge from the germinating seed of a eudicot such as the garden bean. The radicle will eventually develop into the primary root of the plant. The shoot hook and cotyledons emerge after the radicle. The ovary is part of the flower structure and not directly involved in the germination of the seed.

Question 8

One assumption about plant reproduction is that because it requires so much matter and energy, reproductive output is resource-limited. Which statement provides evidence that this assumption may be incorrect?

Accepted Answer

The fact that hand-pollinated plants produce more seeds than naturally pollinated plants suggests that the reproductive output of plants may not be entirely resource-limited, as human intervention can significantly increase seed production. This implies that factors other than resources, such as pollination efficiency, can influence the amount of offspring that a plant produces. The other answer choices, while relevant to plant reproduction, do not directly contradict the assumption that reproductive output is resource-limited.

Question 9

In angiosperms, the process of ________ ensures that the endosperm will develop only in ovules containing a fertilized egg.

Accepted Answer

Double fertilization occurs in angiosperms where two sperm cells from the pollen tube unite with the egg and polar nuclei in the embryo sac. This results in the formation of the zygote and endosperm. The process ensures that the endosperm will develop only in ovules containing a fertilized egg, as the second sperm cell fuses with the polar nuclei to form the endosperm.

Question 10

Foreign genes can be inserted into a single plant cell that is then cultured to produce

Accepted Answer

When foreign genes are inserted into a single plant cell and this cell is cultured, it can lead to the creation of a genetically modified plant. This is because the inserted genes will be incorporated into the plant's DNA and will be expressed in its cells, leading to new traits or abilities. The resulting plant will carry these genetically modified traits in all its tissues, including its seeds. However, this process does not create a new plant species or clones of the organisms from which the genes were taken.

Question 11

A seed develops from a(n)

Accepted Answer

A seed develops from an ovule, which is a small structure found in the ovary of a flower. The ovule becomes fertilized by pollen, which then develops into a seed. While fruits may contain seeds, the actual seed itself develops from the ovule within the fruit.

Question 12

The genetically identical organisms that result from asexual reproduction are called

Accepted Answer

A clone is an exact genetic replica of its parent organism. Asexual reproduction creates genetically identical offspring without the need for fertilization or genetic recombination, resulting in a clone. Seeds and seedlings are not generally associated with asexual reproduction.

Question 13

What is an advantage of cloning horticultural crops rather than using sexual propagation to grow them?

Accepted Answer

Cloning plants allows for large production of plants with minimal effort and expense, making it more cost-effective and efficient compared to sexual propagation.

Question 14

Aspen trees are the most widely distributed tree in North America. A forest of many aspen trees, some of which may be tens of thousands of years old, is actually one single clone. What is likely to be the greatest threat to the long-term survival of aspen forests?

Accepted Answer

Climate change is likely to have the greatest threat to the long-term survival of aspen forests as it is altering the aspen trees' typical moist and cool environment to a dry and warm one. This can lead to reduced growth, increased susceptibility to pests and diseases, and changes in ecological interactions with other species. The other options listed may also pose a threat, but are unlikely to have as significant an impact on the survival of aspen forests as climate change.

Question 15

Which statement about germination is false?

Accepted Answer

Germination is not the beginning of life for a seed; it is the process by which a seed emerges from a period of dormancy and begins to sprout, indicating that life began at fertilization when the seed was formed.

Question 16

A mature ovary, specialized as a vessel that houses and protects seeds, is a

Accepted Answer

A mature ovary that houses and protects seeds is known as a fruit. The other options mentioned (ovule, cotyledon, and seed coat) are all part of the structure of a seed within the fruit, but they do not describe the mature ovary itself.

Question 17

What is the evolutionary advantage of the very long life span of some plants?

Accepted Answer

The long lifespan of some plants allows them to produce many offspring over many years, which increases their chances of passing on their genes and thriving in their environment. This is particularly advantageous in environments where there may be a lot of competition for resources or where conditions may fluctuate over time. Plants with short lifespans may not have the same opportunity to produce as many offspring and may be more susceptible to environmental fluctuations.

Question 18

What happens to the cotyledons of pea and maize (corn) seeds?

Accepted Answer

Cotyledons of pea and maize seeds remain in the soil after the seed germinates and eventually decompose. They provide the initial nutrients required for the seedling's growth but do not emerge from the soil or participate directly in photosynthesis.

Question 19

Which plant parts commonly contribute to asexual reproduction?

Accepted Answer

Roots are a common plant part that contribute to asexual reproduction through processes such as rhizomes, stolons, and tubers. Seeds, flowers, and fruits are typically involved in sexual reproduction.

Question 20

A number of studies have found that for many plants there is an increase in seed production under conditions of elevated carbon dioxide levels. What is a likely explanation for this phenomenon?

Accepted Answer

Plants use carbon dioxide during photosynthesis to produce new organic molecules, including the components of seeds. Therefore, an increase in carbon dioxide levels can provide more carbon for plants to use in seed production.

Quiz 31: Plant Structure, Growth, and Reproduction