Lecture: Chapter 29 2/16/12 Bryophyte sporophytes The life cycle of a moss Figure 29.8 Ecological and economic importance of mosses Seedless vascular plants Vascular plants began to evolve during the Carboniferous period (~300-60 mya). The life cycle of a fern Figure 29. Phylum lycophyta: club mosses, spike mosses, and quillworts Are relics from a far more eminent past Are small herbaceous plants Phylum Pterophyta: ferns, horsetails, and whisk ferns, and relatives Ferns are most diverse seedless vascular plants The significance of seedless vascular plants The ancestors of modern lycophytes, horsetails, and ferns grew to great heights during the Carboniferous, forming the first forests. You should know: Describe four shared characteristics and four distinct characteristics between charophytes and land plants. Distinguish between the phylum Bryophyta and bryophytes. Diagram and label the life cycle of a bryophyte. Explain why most bryophytes grow close to the ground and are restricted to periodically moist environments. Describe three traits that characterize modern vascular plants and explain how these traits have contributed to success on land. Explain how vascular plants differ from bryophytes. Distinguish between the following pairs of terms: microphyll and megaphyll; homosporous and Heterosporous.  Diagram and label the life cycle of a seedless vascular plant.Chapter 30 plant diversity II the evolution of seed plants Overview: transforming the world Seeds changed the course of plant evolution, enabling their bearers to become the dominant producers in the most terrestrial ecosystems. Figure 30.2 Ovules and production of eggs An ovule consists of a megasporangium, megaspore, and one or more protective integuments. The evolutionary advantage of seeds Seeds provide some evolutionary advantages over spores They may remain dormant for days to years, until conditions are favorable for germination. They may be transported long distances by wind or animals. 30.2: gymnosperms bear “naked” seeds, typically on cones Gymnosperms appear early in the fossil record (~360 mya)and dominated the Mesozoic terrestrial ecosystems. Exploring gymnosperm diversityLecture Chapter 30 plant diversity II 2/21/12 Fruits are classified into several types Depending on their developmental origin Evolutionary links between angiosperms and animals Pollination of flowers by animals and transport of seeds by animals Are 2 important relationships in terrestrial ecosystems Chapter 38- plant reproduction The embryo and its food supply are enclosed by a hard, protective seed coat In a eudicot, the embryo consists of the hypocotyl, radicle, and thick cotyledons The embryo of the monocot has a single cotyledon, a coleoptile, and a coleorhiza Eudicot seed germination Figure Monocot seed germination The coleoptile pushes upward through the soil and into the airLecture: chapter 30 – plant diversity II 2/23/12 Mechanisms of asexual reproduction In some species the root system of a single parent gives rise to many adventitious shoots that become separate shot systems. Human welfare depends greatly on seed plants Table 30.1 Five derived traits of seed plants Table You should know: Explain why pollen grains were an important adaptation for successful reproduction on land List and distinguish among the four phyla of gymnosperms Describe the life history of a pine; indicate which structures are part of the gametophyte generation and which are part of the sporophyte generation Identify and describe the function of the following floral structures: sepals, petals, stamens, carpels, filament, anther, stigma, style, ovary, and ovule Explain how fruits may be adapted to disperse seeds Diagram the generalized life cycle of an angiosperm; indicate which structures are part of the gametophyte generation and which are part of the sporophyte generation Describe the current threat to plant diversity caused by human population growthChapter 35 and 36 The 3 basic plant organs: roots, stem, and leaves 3 basic organs evolved: roots, stem, and leaves Roots The absorption of water and minerals occurs near the root tips, where vast numbers of tiny root hairs increase the surface area of the root. Many plants have modified roots Figure 35.4 Many plants have modified stems Figure Leaves In classifying angiosperms taxonomists may use leaf morphology as a criterion Figure 35.6 Modified leaves serve various functions Figure  The 3 tissue systems: dermal, vascular and ground Each plant organ has dermal, vascular and ground tissues. Common types of plant cells Parenchyma Thin flexible walls Carry out synthesis and storage of organic compounds, cells alive at maturity Collenchyma Thicker cell walls, primarily at corners Gives flexible support to growing plant, cells alive Sclerenchyma Have thick 2 cell walls with lignin Cells dead at maturity Gives strong support, consists of schlereids and fibers Water –conducting cells of the xylem and sugar-conducting cells of the phloem Figure 35.10 An overview of primary and secondary growth Figure 35.10Lecture chapter 35 and 36 2/28/12 Primary growth of roots The root tip is covered by a root cap, which protects the delicate apical meristem as the root pushes through soil during primary growth Organization of primary tissues in young roots Figure  Lateral roots arise from within the pericycle, the outermost cell layer in the vascular cylinder. Primary growth of shoots A shoot apical meristem Figure Tissue organization of stems In gymnosperms and most eudicots:  Figure Monocot stems: Figure Tissue organization of leaves Leaf anatomy Figure 35.17 Secondary growth adds girth to stem and roots in woody plants Secondary growth -occurs in stems and roots of woody plants but rarely in leaves The secondary plant body -consists of the tissues produced by the vascular cambium and cork cambium. The vascular cambium -is a cylinder of meristematic cells one cell thick -develops from parenchyma cells Primary and secondary growth of a stem Figure Cross section of secondary growth Tree rings: Early wood- secondary xylem with thinner cell walls and large