Exam 26: The Colonization of Land by Plants and Fungi

Entrepreneurs attempted, but failed, to harvest nuts from plantations grown in Southeast Asia. Attempts to grow Brazil nut trees in South American plantations also failed. In both cases, the trees grew vigorously, produced healthy flowers in profusion, but set no fruit. Consequently, what is the likely source of the problem?

In onions (Allium), cells of the sporophyte have 16 chromosomes within each nucleus. Match the number of chromosomes present in each of the following onion tissues. -How many chromosomes should be in a tube cell nucleus?

What is the greatest threat to plant diversity?

Figure 26.2 depicts the outline of a large fairy ring that has appeared overnight in an open meadow, as viewed from above. The fairy ring represents the furthest advance of this mycelium through the soil. Locations A-D are all 0.5 meters below the soil surface. Responses may be used once, more than once, or not at all. Figure 26.2 -Which location is nearest to basidiocarps?

Figure 26.2 depicts the outline of a large fairy ring that has appeared overnight in an open meadow, as viewed from above. The fairy ring represents the furthest advance of this mycelium through the soil. Locations A-D are all 0.5 meters below the soil surface. Responses may be used once, more than once, or not at all. Figure 26.2 -At which location is the mycelium currently absorbing the most nutrients per unit surface area, per unit time?

What is thought to be the correct sequence of the following events during the Carboniferous period? 1. vascular plants become more prevalent 2) megaphylls with large surface areas become more prevalent 3) atmospheric CO2 levels decline by a factor of five 4) global cooling occurs, leading to widespread glaciations

For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection. -Apart from direct amphibian-to-amphibian contact, what is the most likely means by which the zoospores spread from one free-living amphibian to another?

Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 10 inches per year. Yet, it is not uncommon when hiking in this bone-dry desert to encounter mosses and ferns. One such plant is called "flower of stone." It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant." At first glance, it could be a fern, a true moss, or a spike moss. -Upon closer inspection of the leaves of flower of stone, one can observe tiny, cone-like structures. Each cone-like structure emits spores of two different sizes. Further investigation also reveals that the roots of flower of stone branch only at the growing tip of the root, forming a Y-shaped structure. Consequently, flower of stone should be expected to possess which other characteristics? 1. a gametophyte generation that is dominant 2) lignified vascular tissues 3) microphylls 4) filamentous rhizoids, but not true roots 5) spores that are diploid when mature

The next few questions refer to the following phylogenetic trees. I. II. III. IV. -Which tree depicts the microsporidians as a sister group of the fungi, rather than as a fungus?

When adult amphibian skin harbors populations of the bacterium, Janthinobacterium lividum (Jl), chytrid infection seems to be inhibited. Which of the following represents the best experimental design for conclusively determining whether this inhibition is real?

For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection. -Sexual reproduction has not been observed in Bd. A Bd sporangium initially contains a single, haploid cell. Which of the following processes must be involved in generating the multiple zoospores eventually produced by each sporangium? 1. S phase 2) cytokinesis 3) mitosis 4) meiosis

Lichens are symbiotic associations of fungi and

If intelligent extraterrestrials visited Earth 475 million years ago, and then again 300 million years ago (at the close of the Carboniferous period), what trends would they have noticed in Earth's terrestrial vegetation over this period? 1. a trend from dominant gametophytes to dominant sporophytes 2) a trend from sporangia borne on modified leaves (sporophylls) to sporangia borne on stalks (seta) 3) a trend from no true leaves, to microphylls, to megaphylls 4) a trend from soil-surface-hugging plants to "overtopping" plants 5) a trend toward increased lignification of conducting systems

In addition to seeds, which of the following characteristics is unique to the seed-producing plants?

Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 10 inches per year. Yet, it is not uncommon when hiking in this bone-dry desert to encounter mosses and ferns. One such plant is called "flower of stone." It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant." At first glance, it could be a fern, a true moss, or a spike moss. -In which combination of locations would one who is searching for the gametophytes of flower of stone have the best chance of finding them? 1. moist soil 2) underground, nourished there by symbiotic fungi 3) south- or west-facing slopes 4) permanently shady places 5) far from any flower of stone sporophytes

Figure 26.3 -What is true of the phylogenetic tree in Figure 26.3? 1. It depicts uncertainty about whether the bryophytes or the vascular plants evolved first. 2) It is hypothetical. 3) It includes polytomies. 4) It shows that ferns (phylum Pterophyta) are the closest living relatives to the seed plants. 5) It indicates that seeds are a shared ancestral character of all vascular plants.

Arrange the following in the correct sequence, from earliest to most recent, in which these plant traits originated. 1. sporophyte dominance, gametophyte independence 2) sporophyte dominance, gametophyte dependence 3) gametophyte dominance, sporophyte dependence

Evidence indicates that plants increase the number of stomata in their leaves as atmospheric CO2 levels decline. Increasing the number of stomata per unit surface area should have the effect of doing which of the following? 1. increasing dehydration of leaf tissues 2) decreasing dehydration of leaf tissues 3) countering the effect of declining CO2 on photosynthesis 4) reinforcing the effect of declining CO2 on photosynthesis 5) decreasing the O2 content of air next to the leaves lower than it would otherwise be 6) increasing the O2 content of air next to the leaves higher than it would otherwise be

The following questions refer to the generalized life cycle for land plants shown in Figure 26.1. Each number within a circle or square represents a specific plant or plant part, and each number over an arrow represents either meiosis, mitosis, or fertilization. Figure 26.1 -Meiosis is most likely to be represented by which number(s) in Figure 26.1?

Which of the following characteristics is unique to chytrids compared to other groups of fungi?