Chapter 29 Reading Quiz 1. 2. 3. 4. 5. About how many species of plants inhabit earth today? What are the two generations in the “alternation of generations”? What structure made of waxes coats most land plant’s leaves? What is the purpose of the structure in #3? Which vascular tissue transports water & minerals? 1. List the characteristics that distinguish plants from organisms in the other kingdoms. Plants: • Are multicellular photosynthetic eukaryotic autotrophs • have cell walls with cellulose • Store food as starch 2. Diagram a generalized plant life cycle indicating which generation is sporophyte/gametophyte, which individuals are haploid/diploid, where meiosis occurs and where mitosis occurs. 3. Describe four major periods of plant evolution that opened new adaptive zones on land. 1. 475 million years ago origin of plants from aquatic ancestors (green algae) 2. 400 million years ago diversification of seedless vascular plants 3. 360 million years ago origin of seed plants 4. 130 million years ago beginning of the flowering plants 4. Distinguish between the categories division and phylum. • Division is the same as phylum, but in plants • For example: in plants the taxonomic order is Kingdom Division (instead of Phylum) Class Order Family Genus Species 5. Using the classification scheme presented in the text, list the plant divisions; give the common name for each; and categorize them into nonvascular, vascular seedless and vascular seed plants. Nonvascular • Bryophyta mosses • Hepatophyta liverworts • Anthocerophyta hornworts Seedless Vascular • Lycophyta lycophytes • Sphenophyta horsetails • Pterophyta ferns continued… #5 continued… Vascular seeds 1. Gymnosperms • Coniferophyta conifers • Cycadophyta cycads • Ginkgophyta ginkgoes • Gnetophyta gnetae 2. Angiosperms • Anthophyta flowering plants 6. Provide evidence to defend the position that plants evolved from green algae. Homologies in: • Cell wall composition (cellulose) • Structure and pigmentation of chloroplasts • Biochemical similarity showing a genetic relationship 7. Describe three adaptations that made bryophytes’ move onto land possible. 1. Waxy cuticles (prevents dessication, or drying out on land) 2. Protection of gametes (seed coat, tough membranes) 3. Protection of developing embryos 8. Explain how bryophytes are still tied to water. • They still need water to reproduce – flagellated sperm swim to egg • No vascular tissue to carry water – must happen through diffusion, capillary action, and cytoplasmic streaming 9. List and distinguish among the three divisions of Bryophytes. Bryophyta the mosses • Rhizoids grip ground • have stem & leaflike structures Hepatophyta the liverworts • Bodies divided into lobes • Can reproduce asexually from gemmae Anthocerophyta the hornworts • Sporophyte is horn-shaped • Cells have one large chloroplast • Most closely related to vascular plants 10. Diagram the life cycle of a moss including gamete production, fertilization, and spore production. 1. 2. 3. 4. 5. 6. 7. Separate male and female gametophytes with antheridia and archegonia Sperm swims to archegonium and fertilizes egg Diploid zygote divides by mitosis and develops into an embryonic sporophyte Sporophyte grows from archegonium and remains attached Top of sporophyte is sporangium where meiosis occurs and haploid spores develop – spores scatter Spores germinate by mitotic development Haploid protonema continue to grow and differentiate eventually forming sexually mature gametophytes, completing the life cycle 11. Compare environmental conditions faced by algae in an aquatic environment and plants in a terrestrial environment. Obvious issues: • Algae live in water; don’t need vascular tissue or seeds • Plants live on land where it’s dry; need seeds and vascular tissue to survive most effectively 12. Provide evidence that suggests the division Bryophyta is a phylogenetic branch separate from vascular plants. • The life cycle is different the haploid gametophyte is the dominant generation in mosses and other bryophytes; the sporophytes are smaller and depend on the gametophyte for water and nutrients 13. Describe six adaptations of vascular plants, including modifications of the life cycle and modifications of the sporophyte that have contributed to their success on land. 1. 2. 3. 4. 5. 6. Regional specialization of the plant body (roots, stems, leaves) Structural support – lignin embedded into cellulose Vascular system – xylem (water) and phloem (food) Pollen – eliminated need for water to transport gametes Seeds Increased dominance of diploid sporophyte 14. List and distinguish among the three extant (not extinct) divisions of seedless vascular plants. Lycophyta the club mosses and ground pines • Rhizomes and true leaves Sphenophyta the horsetails • Live in damp locations with flagellated sperm • Are homosporous with a conspicuous sporophyte • Have free-living gametophytes Pterophyta about 12,000 species of ferns • Dominant sporophyte, homosporous, free-living gametophyte • Water needed for fertilization 15. Distinguish between homosporous and heterosporous. • Homosporous - produces a single type of spore - each spore develops into a plant with both sex organs • Heterosporous - produces 2 types of spores 1. Megaspores – female with archegonia 2. Microspores – male with antheridia 16. Distinguish among spore, sporophyte, sporophyll, and sporangium. Spore – haploid cell that produces the gametophyte Sporophyte – multicellular diploid form resulting from the union of gametes; produces spores Sporophyll – where sporangia are found – leaves that are specialized for reproduction Sporangium – capsule in which meiosis occurs and haploid spores develop 17. Diagram the life cycle of a fern including spore production, gamete production and fertilization. • Spore production in sporangium from the sporophyte • Gamete production from the antheridium and archegonium on the gametophyte • Fertilization egg (n) + sperm (n) becomes zygote (2n) and grows to become new sporophyte 18. Point out the major life cycle differences between mosses and ferns. sporophyte is dominant in ferns, not in mosses Spores are protected by sporopollenin in ferns, not mosses 19. Describe how coal is formed and during which geological period the most extensive coal beds were produced. happened in the Carboniferous period - organic rubble of the seedless plants accumulated as peat - later it was covered by the sea and sediments, heat and pressure transformed the peat into coal The End!