Plant Diversity I: How Plants Colonized Land Chapter 29 Plant Diversity I: How Plants Colonized Land Questions prepared by Eric Ribbens Western Illinois University Michael Dini Texas Tech Univeristy

Which of the following are the closest algal relatives of land plants? a) psilophytes b) charophytes c) chrysophytes d) bacillariophytes e) rhodophytes Answer: b

The textbook describes the many similarities between the Charophyta and the land plants (Embryophyta). Then the textbook asserts that while this implies an evolutionary relationship, it is not necessarily true that the land plants evolved from the modern-day Charophyta. What is a likely alternative explanation? Land plants evolved from another group of algae. Both land plants and Charophyta have evolved from a more primitive group. Land plants are the ancestors of Charophyta. Land plants are paraphyletic. Land plants are polyphyletic. Answer: b

The relationship between a gametophyte and a sporophyte in a liverwort is like the relationship between a brother and a sister. a grandparent and a grandchild. an uncle and a nephew. a parent and a child. two cousins. Answer: d

Before land plants evolved, life on land probably consisted of rocks covered by thin films of cyanobacteria. This implies that before plants, photosynthesis did not happen. plants evolved from cyanobacteria. rocks did not contain nutrients. there were no eukaryotes. terrestrial ecosystems were very simple. Answer: e

Plants that evolved vascular tissue are more advanced than plants without vascular tissue. One of the consequences is that vascular tissue enabled plants to reproduce via spores. store water. grow taller. develop stomata. support large gametophytes. Answer: c

One thing you should be able to conclude from this figure is that gametophytes have less DNA than sporophytes. gametophytes evolved before sporophytes. gametophytes are less important than sporophytes. gametophytes grow from sporophytes. gametophyte cells come about by mitosis; sporophyte cells come about by meiosis. Answer: a Gametophytes, being haploid, have half as much as diploid sporophytes

The following graph describes Richard Bowden’s experiment The following graph describes Richard Bowden’s experiment. If the two bars were the same height, we could conclude that moss doesn’t use nitrogen. gets its nitrogen from the soil. doesn’t accumulate nitrogen. gets its nitrogen from photosynthesis. doesn’t affect other plants growing there. Answer: c

The bars in the graph are very different The bars in the graph are very different. The fact that, without moss, nitrogen loss is much higher implies that Richard Bowden should have known moss was important. sandy soils with moss probably have more nitrogen available than soils without moss. moss is able to capture nitrogen from the atmosphere. moss uses so much water that leaching doesn’t happen. mosses harbor nitrogen-fixing cyanobacteria. Answer: b

Stomata are found in every group of sporophyte plants except the liverworts. According to the hypothesis that stomata evolved only once among the bryophytes, this is evidence that liverworts resemble the most primitive plants. liverworts don’t need to exchange gases with the atmosphere. liverworts have lost the ability to make stomata. liverworts are able to fix nitrogen. gametophytes are more important in liverworts. Answer: a

This figure implies that red algae and chlorophytes form a monophyletic clade. if the three groups of algae (red algae, chlorophytes, and charophytes) formed a kingdom, it would be paraphyletic. alternation of generations unites all four taxa into a monophyletic kingdom. all organisms that have chlorophylls a and b belong to a monophyletic kingdom. Answer: b

There are several pieces of evidence that ferns are derived from more primitive plants. Of the following fern characteristics, which one does NOT link them to more primitive plants? homospory stomata in sporophytes megaphylls separate free-living gametophytes lack of seeds Answer: c

Protonema have large surface-area-to-volume ratios Protonema have large surface-area-to-volume ratios. From this, you can predict that protonema should be big. probably are important in reproduction. secrete digestive enzymes. have stomata and other openings. are absorptive interfaces with the environment. Answer: e