* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Seeds - Del Mar College
Plant use of endophytic fungi in defense wikipedia , lookup
Plant breeding wikipedia , lookup
History of herbalism wikipedia , lookup
History of botany wikipedia , lookup
Plant physiology wikipedia , lookup
Plant ecology wikipedia , lookup
Ornamental bulbous plant wikipedia , lookup
Plant morphology wikipedia , lookup
Ecology of Banksia wikipedia , lookup
Gartons Agricultural Plant Breeders wikipedia , lookup
Perovskia atriplicifolia wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Ficus macrophylla wikipedia , lookup
Fertilisation wikipedia , lookup
Pollination wikipedia , lookup
Plant reproduction wikipedia , lookup
The Land Plants Chapter 23 Part 2 23.5 Ancient Carbon Treasures In the Carboniferous, plants with ligninreinforced tissues flourished, died, and became compacted into coal, a nonrenewable fossil fuel • Lepidodendron, a Carboniferous lycophyte Energy from the Carboniferous Forest stem of a giant lycophyte (Lepidodendron), which grew 40 meters (131 feet) tall Medullosa , one of the early seed plants stem of a giant horsetail (Calamites), which was almost 20 meters (66 feet) tall Fig. 23-16a, p. 378 Fig. 23-16b, p. 378 23.4-23.5 Key Concepts Seedless Vascular Plants Lycophytes, whisk ferns, horsetails, and ferns have vascular tissues but do not produce seeds A large spore-producing body that has internal vascular tissues dominates the life cycle As with bryophytes, sperm swim through water to reach eggs 23.6 Seed-Bearing Plants Seeds and pollen allowed gymnosperms and angiosperms (flowering plants) to survive and thrive in drier habitats Modified Spores Microspores become sperm-producing male gametophytes (pollen grains) Megaspores develop into egg-producing female gametophytes inside ovules Pollen Seed plants release pollen grains which allow fertilization to occur even in the absence of environmental water pine pollen grains p. 379 Seeds A seed is a mature ovule • Includes nutritive tissue and a tough seed coat that protects the embryo sporophyte inside the seed from harsh conditions Human Use of Seed Plants Humans depend heavily on cultivated seed plants and have contributed to the widespread dispersal of seed plants that they favor • • • • Food crops Lumber and wood product Drugs and medicines Fabrics and dyes Edible Flowering Plants Fig. 23-17a, p. 379 Fig. 23-17b, p. 379 Fig. 23-17c, p. 379 Fig. 23-17d, p. 379 23.7 Gymnosperms— Plants With Naked Seeds Gymnosperms • Vascular seed plants with “naked” seeds • One of the two modern lineages of seed plants Gymnosperms include conifers (such as pines), cycads, ginkgos, and gnetophytes Some Gymnosperms Fig. 23-18a, p. 380 Fig. 23-18b, p. 380 Fig. 23-18c, p. 380 Fig. 23-18d, p. 380 Fig. 23-18e, p. 380 Fig. 23-18f, p. 380 Fig. 23-18g, p. 380 Fig. 23-18h, p. 380 Gymnosperm Life Cycle Gymnosperms release pollen and seeds Ovules form in in strobili or, in the case of conifers, in woody cones Conifer Life Cycle: Ponderosa Pine A A female cone has many scales, each with two ovules, on its upper section through one surface. ovule (the red “cut” in the diagram to the left) I Seed is released, seed coat germinates, and the embryo grows and embryo develops into a new nutritive sporophyte. H Ovule develops tissue into a mature seed. surface view of female cone scale ovule B A male cone has section many scales, each through pollenhousing a pollen producing sac. sac ( red cut) surface view of male cone scale G One sperm nucleus fertilizes the egg, forming a zygote. fertilization spermproducing cell pollen tube F Pollen grain matures into male gametophyte. Two nonflagellated sperm nuclei form as pollen tube grows through ovule tissue. (view inside ovule) eggs Diploid Stage Haploid Stage meiosis E Pollination: wind deposits pollen grain on seed cone. female gametophyte C Megaspores form by meiosis; one develops into the female gametophyte. D Microspores form by meiosis, develop into pollen grains. Fig. 23-19, p. 381 Animation: Pine life cycle 23.8 Angiosperms— The Flowering Plants Angiosperms are the most diverse plant lineage and the only plants that make flowers and fruits In the Mesozoic, angiosperms began adaptive radiation to all land and many aquatic habitats Adaptive Radiation of Angiosperms Keys to Angiosperm Success Short life cycles and rapid growth Specialized reproductive structures (flowers) Specialized pollination and dispersal structures • Wind and animal pollinators • Fruits that float or stick • Seeds that survive animal digestive tracts Specialized Angiosperm Structures A flower is a specialized reproductive shoot Seeds develop inside the ovaries (chambers that enclose ovules) of flowers After fertilization, an ovary becomes a fruit Flower Structures petal stamen (microspores form here) sepal carpel (megaspores form here) ovule in an ovary Fig. 23-21, p. 382 Pollination and Coevolution Pollinators • Animals (such as insects that feed on pollen) move pollen grains from male parts of one flower to female parts of another Coevolution • Over time, plants and their animal pollinators jointly evolved; changes in one exerts selection pressure on the other Flowering Plant Diversity Fig. 23-22a, p. 383 Fig. 23-22b, p. 383 Fig. 23-22c, p. 383 Fig. 23-22d, p. 383 Fig. 23-22e, p. 383 Fig. 23-22f, p. 383 Fig. 23-22g, p. 383 Amborella water lilies star anise magnoliids monocots eudicots basal groups Fig. 23-22g, p. 383 23.9 Focus on a Flowering Plant Life Cycle Flowering plants form eggs in ovaries and pollen in stamens Flowering plants make fruits containing seeds which supply their embryo sporophytes with endosperm, a nutritive tissue Life Cycle: Lilium A a flowering stem of the mature sporophyte seedling (2n) seed coat pollen sac, where embryo (2n) each one of many endosperm cells will give rise (nutritive tissue) to microspores seed Diploid Stage meiosis E double fertilization Haploid Stage B D Pollination and Microspores pollen tube formation: form, then male develop gametophyte into pollen pollen tube grains. sperm (n) sperm (n) Pollen is released. The pollen tube enters an ovule. One sperm will fertilize the egg, one will fertilize the endospermproducing cell. (line of cut of diagram at left) ovary ovules inside ovary cell in ovule that will give rise to a megaspore C meiosis cell from which endosperm will form egg Four megaspores form. Three disintegrate. One undergoes three rounds of mitosis without any cytoplasmic division. Nuclei migrate and cell walls form. The resulting female gametophyte includes the egg and a cell with two nuclei that will form endosperm. female gametophyte Fig. 23-23, p. 384 seedling seed coat embryo (2n) endosperm (nutritive tissue) A a flowering stem of the mature sporophyte (2n) pollen sac, where each one of many cells will give rise to microspores ovules inside ovary cell in ovule that will give rise to a megaspore seed Diploid Stage meiosis E double fertilization Haploid Stage B Microspores D Pollination and pollen form, then tube formation: male develop gametophyte into pollen grains. pollen tube sperm (n) sperm (n) Pollen is released. The pollen tube enters an ovule. One sperm will fertilize the egg, one will fertilize the endospermproducing cell. C meiosis cell from which endosperm will form egg (line of cut of diagram at left) ovary female gametophyte Four megaspores form. Three disintegrate. One undergoes three rounds of mitosis without any cytoplasmic division. Nuclei migrate and cell walls form. The resulting female gametophyte includes the egg and a cell with two nuclei that will form endosperm. Stepped Art Fig. 23-23, p. 384 Animation: Monocot life cycle 23.10 The World’s Most Nutritious Plant Botanists use knowledge of plant biology and genetics to find new ways to feed a hungry world Example: Alejandro Bonifacio studies quinoa, a nutritious native South American grain Alejandro Bonifacio and Genetically Modified Quinoa 23.6-23.10 Key Concepts Seed-Bearing Vascular Plants Gymnosperms and, later, angiosperms radiated into higher and drier environments Both produce pollen and seeds Nearly all crop plants are seed plants In angiosperms, flowers and fruits further enhanced reproductive success Summary: Plant Evolutionary Trends Bryophytes Seedless vascular plants • Nonvascular • Vascular tissue present • Vascular tissue present • Vascular tissue present • Haploid dominance • Diploid dominance • Diploid dominance • Diploid dominance • Water required for fertilization • Seedless • Water required for fertilization • Seedless whisk ferns, club mosses, horsetails, spike mosses ferns • Pollen grains; water not required for fertilization • “Naked” seeds • Seeds form inside an ovary that develops into a fruit liverworts mosses hornworts Gymnosperms gnetophytes, ginkgos, conifers, cycads Angiosperms monocots, dicots, magnoliids, basal groups ancestral alga Fig. 23-25, p. 386 Animation: Flower parts Animation: Pinus cones Video: Beginnings and endings