© 2015 Pearson Education, Inc. PowerPoint Lectures Campbell Biology: Concepts & Connections, Eighth Edition REECE TAYLOR SIMON DICKEY HOGAN Chapter 17 Lecture by Edward J. Zalisko The Evolution of Plant and Fungal Diversity

© 2015 Pearson Education, Inc. Introduction Mutually beneficial symbioses, called mycorrhizae, between plants and fungi began millions of years ago, when plants first occupied land. These intimate associations allow the plant to tap a vast underground network of fungal filaments into which water and mineral nutrients flow. Plants supply mycorrhizae with sugars and other organic molecules. At least 80% of all plants form such relationships.

© 2015 Pearson Education, Inc. Figure

© 2015 Pearson Education, Inc. Figure Plant Evolution and Diversity Chapter 17: Big Ideas Diversity of Fungi Alternation of Generations and Plant Life Cycles Gametophyte plant (n) FertilizationMeiosis Sporophyte plant (2n)

© 2015 Pearson Education, Inc. P LANT E VOLUTION AND D IVERSITY

© 2015 Pearson Education, Inc Plants have adaptations for life on land More than 500 million years ago, the algal ancestors of plants may have carpeted moist fringes of lakes and coastal salt marshes. Plants and green algae called charophytes. They are: are thought to have evolved from a common ancestor, have complex multicellular bodies, and are photosynthetic eukaryotes. Some species accumulated adaptations that enabled them to live permanently above the water line.

© 2015 Pearson Education, Inc. Figure 17.1a Chara, an elaborate charophyte Coleochaete, a simple charophyte

© 2015 Pearson Education, Inc Plants have adaptations for life on land Life on land offered many opportunities for plant adaptations that took advantage of unlimited sunlight, abundant CO 2, and initially, few pathogens or herbivores.

© 2015 Pearson Education, Inc Plants have adaptations for life on land But life on land had disadvantages, too. On land, plants must maintain moisture inside their cells, to keep from drying out, support their body in a non-buoyant medium, reproduce and disperse offspring without water, anchor their bodies in soil, and obtain resources from soil and air.

© 2015 Pearson Education, Inc Plants have adaptations for life on land Unlike land plants, algae live almost entirely in or on the surface of water generally have no rigid tissues, are supported by surrounding water, obtain water, CO 2 and minerals directly from the water surrounding the entire algal body, receive light and perform photosynthesis over most of their body, use flagellated sperm that swim to fertilize an egg, and disperse offspring by water.

© 2015 Pearson Education, Inc. Figure 17.1c-0 Spores Key Vascular tissue Leaf Stem Roots Flagellated sperm Holdfast Holdfast (anchors alga) Pollen Seed Leaf Flagellated sperm Roots Stem Leaf Alga Surrounding water supports alga. Whole alga performs photosynthesis; absorbs water, CO 2, and minerals from the water. Moss Stomata only on sporophytes; primitive roots anchor plants; no lignin; no vascular tissue; fertilization requires moisture Fern Stomata; roots anchor plants, absorb water; lignified cell walls; vascular tissue; fertilization requires moisture Pine tree Stomata; roots anchor plants, absorb water; lignified cell walls; vascular tissue; fertilization does not require moisture

© 2015 Pearson Education, Inc Plants have adaptations for life on land Land plants maintain moisture in their cells using a waxy cuticle and cells that regulate the opening and closing of stomata. Land plants obtain water and minerals from roots in the soil, CO 2 from the air, and sunlight through leaves. Growth-producing regions of cell division, called apical meristems, are found near the tips of stems and roots.

© 2015 Pearson Education, Inc Plants have adaptations for life on land In many land plants, water and minerals move up from roots to stems and leaves using vascular tissue. Xylem consists of dead cells and conveys water and minerals, usually up. Phloem consists of living cells and conveys sugars, usually down. (Phloem flows down)

© 2015 Pearson Education, Inc. Figure 17.1d

© 2015 Pearson Education, Inc Plants have adaptations for life on land The cell walls of some plant tissues, including xylem, are thickened and reinforced by a chemical called lignin. The absence of lignified cell walls in mosses and other plants that lack vascular tissue limits their height.

© 2015 Pearson Education, Inc Plants have adaptations for life on land In all plants, gametes and embryos must be kept moist, fertilized eggs (zygotes) develop into an embryo while attached to and nourished by the parent plant, and the life cycle involves an alternation of a haploid generation, which produces eggs and sperm, and a diploid generation, which produces spores within protective structures called sporangia. Pines and flowering plants have pollen grains, structures that contain the sperm-producing cells.

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom Four key adaptations for life on land distinguish the main lineages of the plant kingdom. (see slide 18) 1.Dependent embryos are present in all plants. 2.Lignified vascular tissues mark a lineage that gave rise to most living plants, dividing Bryophytes from Vascular plants. 3.Seeds are found in a lineage that includes all living gymnosperms and angiosperms and that dominates the plant kingdom today but not in club mosses (different from regular mosses) and ferns. 4.Flowers are found in angiosperms but not gymnosperms.

© 2015 Pearson Education, Inc. Figure 17.2a-0 Liverworts Mosses Hornworts Lycophytes (club mosses, spike mosses, quillworts) Monilophytes (ferns, horsetails, whisk ferns) Gymnosperms Angiosperms Land plants Vascular plants Nonvascular plants (bryophytes) Seedless vascular plants Seed plants Millions of years ago (mya) 500 Ancestral green alga Origin of land plants (about 470 mya) Origin of vascular plants (about 425 mya) Origin of seed plants (about 360 mya)

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom Early diversification of plants gave rise to seedless, nonvascular plants called bryophytes, including mosses, liverworts, and hornworts. Bryophytes have apical meristems and embryos retained on the parent plant, but lack true roots, leaves, and lignified cell walls.

© 2015 Pearson Education, Inc. Figure 17.2b-0 MossLiverwort Hornwort

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom About 425 million years ago, vascular plants evolved with lignin-hardened vascular tissues. The seedless vascular plants include lycophytes (including club mosses) and monilophytes (ferns and their relatives).

© 2015 Pearson Education, Inc. Figure 17.2c-0 Club moss (a lycophyte) Fern (a monilophyte)

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom The first vascular plants with seeds evolved about 360 million years ago. A seed consists of an embryo packaged with a food supply within a protective covering.

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom Vascular plants with seeds include gymnosperms (including ginkgo, cycad, and conifer species) and angiosperms (such as flowering trees and grasses).

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom Gymnosperms have naked seeds that are not produced in special chambers and include ginkgo, cycad, and conifer

© 2015 Pearson Education, Inc Plant diversity reflects the evolutionary history of the plant kingdom Angiosperms evolved at least 140 million years ago, are flowering plants, and include flowering trees and grasses. A jacaranda tree Green foxtail, a grass