DOCSLIB.ORG

Vascular Plants (About 425 Mya)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Vascular Plants (About 425 Mya) LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson Chapter 29 Plant Diversity I: How Plants Colonized Land Lectures by Erin Barley Kathleen Fitzpatrick © 2011 Pearson Education, Inc. Overview: The Greening of Earth • For more than the first 3 billion years of Earth’s history, the terrestrial surface was lifeless • Cyanobacteria likely existed on land 1.2 billion years ago • Around 500 million years ago, small plants, fungi, and animals emerged on land © 2011 Pearson Education, Inc. • Since colonizing land, plants have diversified into roughly 290,000 living species • Land plants are defined as having terrestrial ancestors, even though some are now aquatic • Land plants do not include photosynthetic protists (algae) • Plants supply oxygen and are the ultimate source of most food eaten by land animals © 2011 Pearson Education, Inc. Figure 29.1 1 m Concept 29.1: Land plants evolved from green algae • Green algae called charophytes are the closest relatives of land plants © 2011 Pearson Education, Inc. Morphological and Molecular Evidence • Many characteristics of land plants also appear in a variety of algal clades, mainly algae • However, land plants share four key traits with only charophytes – Rings of cellulose-synthesizing complexes – Peroxisome enzymes – Structure of flagellated sperm – Formation of a phragmoplast © 2011 Pearson Education, Inc. Figure 29.2 30 nm 1 m • Comparisons of both nuclear and chloroplast genes point to charophytes as the closest living relatives of land plants • Note that land plants are not descended from modern charophytes, but share a common ancestor with modern charophytes © 2011 Pearson Education, Inc. Figure 29.3 5 mm Chara species, a pond organism Coleochaete orbicularis, a disk-shaped charophyte that also lives in ponds (LM) 40 m 1 m Adaptations Enabling the Move to Land • In charophytes a layer of a durable polymer called sporopollenin prevents exposed zygotes from drying out • Sporopollenin is also found in plant spore walls • The movement onto land by charophyte ancestors provided unfiltered sun, more plentiful CO2, nutrient-rich soil, and few herbivores or pathogens • Land presented challenges: a scarcity of water and lack of structural support © 2011 Pearson Education, Inc. • The accumulation of traits that facilitated survival on land may have opened the way to its colonization by plants • Systematists are currently debating the boundaries of the plant kingdom • Some biologists think the plant kingdom should be expanded to include some or all green algae • Until this debate is resolved, we define plants as embryophytes, plants with embryos © 2011 Pearson Education, Inc. Figure 29.4 Red algae Viridiplantae ANCESTRAL Chlorophytes ALGA Streptophyta Charophytes Plantae Embryophytes 1 m Derived Traits of Plants • Four key traits appear in nearly all land plants but are absent in the charophytes – Alternation of generations and multicellular, dependent embryos – Walled spores produced in sporangia – Multicellular gametangia – Apical meristems © 2011 Pearson Education, Inc. Alternation of Generations and Multicellular, Dependent Embryos • Plants alternate between two multicellular stages, a reproductive cycle called alternation of generations • The gametophyte is haploid and produces haploid gametes by mitosis • Fusion of the gametes gives rise to the diploid sporophyte, which produces haploid spores by meiosis © 2011 Pearson Education, Inc. • The diploid embryo is retained within the tissue of the female gametophyte • Nutrients are transferred from parent to embryo through placental transfer cells • Land plants are called embryophytes because of the dependency of the embryo on the parent © 2011 Pearson Education, Inc. Figure 29.5a Key Gamete from Gametophyte another plant Haploid (n) (n) Diploid (2n) Mitosis Mitosis n n n n Spore Gamete MEIOSIS FERTILIZATION 2n Zygote Sporophyte Mitosis (2n) Alternation of generations 1 m Figure 29.5b Embryo (LM) and placental transfer cell (TEM) of Marchantia (a liverwort) Embryo Maternal tissue 2 m Wall ingrowths Placental transfer cell (outlined in 10 m blue) 1 m Walled Spores Produced in Sporangia • The sporophyte produces spores in organs called sporangia • Diploid cells called sporocytes undergo meiosis to generate haploid spores • Spore walls contain sporopollenin, which makes them resistant to harsh environments © 2011 Pearson Education, Inc. Figure 29.5c Spores Sporangium Longitudinal section of Sphagnum sporangium (LM) Sporophyte Gametophyte 1 m Sporophytes and sporangia of Sphagnum (a moss) Multicellular Gametangia • Gametes are produced within organs called gametangia • Female gametangia, called archegonia, produce eggs and are the site of fertilization • Male gametangia, called antheridia, produce and release sperm © 2011 Pearson Education, Inc. Figure 29.5d Female Archegonia, gametophyte each with an egg (yellow) Antheridia (brown), containing sperm Male gametophyte Archegonia and antheridia of Marchantia (a liverwort) 1 m Apical Meristems • Plants sustain continual growth in their apical meristems • Cells from the apical meristems differentiate into various tissues © 2011 Pearson Education, Inc. Figure 29.5e Apical meristem Developing of shoot leaves Apical meristems of plant roots and shoots Apical meristem of root Root Shoot 100 m 1 m 100 m • Additional derived traits include Cuticle, a waxy covering of the epidermis Mycorrhizae, symbiotic associations between fungi and land plants that may have helped plants without true roots to obtain nutrients Secondary compounds that deter herbivores and parasites © 2011 Pearson Education, Inc. The Origin and Diversification of Plants • Fossil evidence indicates that plants were on land at least 475 million years ago • Fossilized spores and tissues have been extracted from 475-million-year-old rocks © 2011 Pearson Education, Inc. Figure 29.6 (a) Fossilized spores (b) Fossilized sporophyte tissue 1 m • Those ancestral species gave rise to a vast diversity of modern plants © 2011 Pearson Education, Inc. Figure 29.7 1 Origin of land plants (about 475 mya) 2 Origin of vascular plants (about 425 mya) 3 Origin of extant seed plants (about 305 mya) Land plants (bryophytes) plants Liverworts Nonvascular ANCESTRAL GREEN 1 Mosses ALGA Hornworts Vascular plants Vascular plants vascular Lycophytes (club Seedless mosses, spike mosses, quillworts) 2 Pterophytes (ferns, horsetails, whisk ferns) Seed plants Seed Gymnosperms 3 Angiosperms 500 450 400 350 300 50 0 Millions of years ago (mya) 1 m • Land plants can be informally grouped based on the presence or absence of vascular tissue • Most plants have vascular tissue; these constitute the vascular plants • Nonvascular plants are commonly called bryophytes • Bryophytes are not a monophyletic group; their relationships to each other and to vascular plants is unresolved © 2011 Pearson Education, Inc. • Seedless vascular plants can be divided into clades – Lycophytes (club mosses and their relatives) – Pterophytes (ferns and their relatives) • Seedless vascular plants are paraphyletic, and are of the same level of biological organization, or grade © 2011 Pearson Education, Inc. • A seed is an embryo and nutrients surrounded by a protective coat • Seed plants form a clade and can be divided into further clades – Gymnosperms, the “naked seed” plants, including the conifers – Angiosperms, the flowering plants © 2011 Pearson Education, Inc. Table 29. 1 1 m Concept 29.2: Mosses and other nonvascular plants have life cycles dominated by gametophytes • Bryophytes are represented today by three phyla of small herbaceous (nonwoody) plants – Liverworts, phylum Hepatophyta – Hornworts, phylum Anthocerophyta – Mosses, phylum Bryophyta • Bryophyte refers to all nonvascular plants, whereas Bryophyta refers only to the phylum of mosses © 2011 Pearson Education, Inc. Figure 29.UN01 Nonvascular plants (bryophytes) Seedless vascular plants Gymnosperms Angiosperms 1 m Bryophyte Gametophytes • In all three bryophyte phyla, gametophytes are larger and longer-living than sporophytes • Sporophytes are typically present only part of the time © 2011 Pearson Education, Inc. Figure 29.8-1 “Bud” Key Male gametophyte Haploid (n) Protonemata (n) Diploid (2n) (n) “Bud” Spores Gametophore Spore dispersal Female gametophyte Peristome (n) Rhizoid Sporangium Seta MEIOSIS Capsule Mature sporophytes (sporangium) Foot 1 m 2 mm 2 Capsule with Female peristome (LM) gametophytes Figure 29.8-2 Sperm “Bud” Antheridia Key Male gametophyte Haploid (n) Protonemata (n) Diploid (2n) (n) “Bud” Egg Spores Gametophore Spore Archegonia dispersal Female gametophyte Peristome (n) Rhizoid FERTILIZATION Sporangium Seta (within archegonium) MEIOSIS Capsule Mature sporophytes (sporangium) Foot 1 m 2 mm 2 Capsule with Female peristome (LM) gametophytes Figure 29.8-3 Sperm “Bud” Antheridia Key Male gametophyte Haploid (n) Protonemata (n) Diploid (2n) (n) “Bud” Egg Spores Gametophore Spore Archegonia dispersal Female gametophyte Peristome (n) Rhizoid FERTILIZATION Sporangium Seta (within archegonium) MEIOSIS Zygote Capsule (2n) Mature sporophytes (sporangium) Foot Embryo Archegonium Young sporophyte 1 m 2 mm 2 (2n) Capsule with Female peristome (LM) gametophytes • A spore germinates into a gametophyte composed of a protonema and gamete-producing gametophore • The height of gametophytes is constrained by lack of vascular tissues • Rhizoids anchor gametophytes to substrate • Mature gametophytes produce flagellated
Load more

Recommended publications
  • Laboratory 8: Ginkgo, Cycads, and Gnetophytes
    IB 168 – Plant Systematics Laboratory 8: Ginkgo, Cycads, and Gnetophytes This is the third and final lab concerning the gymnosperms. Today we are looking at Ginkgo, the Cycads, and the Gnetophytes, the so-called non-coniferous gymnosperms. While these groups do not have cones like the true conifers, many do produce strobili. Order Ginkgoales: leaves simple (with dichotomously branching venation); dimorphic shoots; water-conducting cells are tracheids; dioecious; generally two ovules produced on an axillary stalk or "peduncle"; microsporangiate strobili loose and catkin-like; multi-flagellate sperm. Ginkgoaceae – 1 genus, 1 sp., cultivated relict native to China Tree, tall, stately with curving branches attached to a short trunk. Leaves fan shaped, deciduous, attached in whorls to the end of "short shoots" growing from the longer branches ("long shoots"); veins of the leaves dichotomously branched; dioecious; paired ovules at the end of a stalk and naked, hanging like cherries; seeds enclosed in a fleshy whitish-pink covering. Ginkgo Order Cycadales: pinnately-compound leaves, whorled, attached spirally at the stem apex; main stem generally unbranched; circinate vernation in some representatives; water-conducting cells are tracheids; dioecious; both male and female cones are simple structures; seeds generally large and round, unwinged; numerous microsporangia per microsporophyll; multi-flagellate sperm. Cycadaceae – 1 genus, 17 spp., Africa, Japan, and Australia Stems palm-like and rough, usually not branched; leaves fern-like, pinnately compound, thick and leathery; attached spirally at the stem apex, young pinnae with circinate vernation, leaf bases remaining after the leaves drop; dioecious; whorls of wooly-covered micro- and megasporophylls alternate with whorls of scales and foliage leaves at the stem apex; ovules born along the sporophyll margins; seed almond or plum like; ovules borne along the margin of the leaf- like megasporophyll.
    [Show full text]
  • Ancient Noeggerathialean Reveals the Seed Plant Sister Group Diversified Alongside the Primary Seed Plant Radiation
    Ancient noeggerathialean reveals the seed plant sister group diversified alongside the primary seed plant radiation Jun Wanga,b,c,1, Jason Hiltond,e, Hermann W. Pfefferkornf, Shijun Wangg, Yi Zhangh, Jiri Beki, Josef Pšenickaˇ j, Leyla J. Seyfullahk, and David Dilcherl,m,1 aState Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; bCenter for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China; cUniversity of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China; dSchool of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; eBirmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; fDepartment of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104-6316; gState Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China; hCollege of Paleontology, Shenyang Normal University, Key Laboratory for Evolution of Past Life in Northeast Asia, Ministry of Natural Resources, Shenyang 110034, China; iDepartment of Palaeobiology and Palaeoecology, Institute of Geology v.v.i., Academy of Sciences of the Czech Republic, 165 00 Praha 6, Czech Republic; jCentre of Palaeobiodiversity, West Bohemian Museum in Plzen, 301 36 Plzen, Czech Republic; kDepartment of Paleontology, Geozentrum, University of Vienna, 1090 Vienna, Austria; lIndiana Geological and Water Survey, Bloomington, IN 47404; and mDepartment of Geology and Atmospheric Science, Indiana University, Bloomington, IN 47405 Contributed by David Dilcher, September 10, 2020 (sent for review July 2, 2020; reviewed by Melanie Devore and Gregory J.
    [Show full text]
  • Phlorotannins from Undaria Pinnatifida Sporophyll: Extraction, Antioxidant, and Anti-Inflammatory Activities
    Agricultural and Biosystems Engineering Publications Agricultural and Biosystems Engineering 7-24-2019 Phlorotannins from Undaria pinnatifida Sporophyll: Extraction, Antioxidant, and Anti-Inflammatory Activities Xiufang Dong Dalian Polytechnic University Ying Bai Dalian Polytechnic University Zhe Xu Dalian Polytechnic University Yixin Shi Dalian Polytechnic University Yihan Sun Dalian Polytechnic University See next page for additional authors Follow this and additional works at: https://lib.dr.iastate.edu/abe_eng_pubs Part of the Amino Acids, Peptides, and Proteins Commons, Bioresource and Agricultural Engineering Commons, and the Marine Biology Commons The complete bibliographic information for this item can be found at https://lib.dr.iastate.edu/ abe_eng_pubs/1147. For information on how to cite this item, please visit http://lib.dr.iastate.edu/howtocite.html. This Article is brought to you for free and open access by the Agricultural and Biosystems Engineering at Iowa State University Digital Repository. It has been accepted for inclusion in Agricultural and Biosystems Engineering Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Phlorotannins from Undaria pinnatifida Sporophyll: Extraction, Antioxidant, and Anti-Inflammatory Activities Abstract Undaria pinnatifida sporophyll (U. pinnatifida) is a major byproduct of U. pinnatifida (a brown algae) processing. Its phenolic constituents, phlorotannins, are of special interest due to their
    [Show full text]
  • 81 Vascular Plant Diversity
    f 80 CHAPTER 4 EVOLUTION AND DIVERSITY OF VASCULAR PLANTS UNIT II EVOLUTION AND DIVERSITY OF PLANTS 81 LYCOPODIOPHYTA Gleicheniales Polypodiales LYCOPODIOPSIDA Dipteridaceae (2/Il) Aspleniaceae (1—10/700+) Lycopodiaceae (5/300) Gleicheniaceae (6/125) Blechnaceae (9/200) ISOETOPSIDA Matoniaceae (2/4) Davalliaceae (4—5/65) Isoetaceae (1/200) Schizaeales Dennstaedtiaceae (11/170) Selaginellaceae (1/700) Anemiaceae (1/100+) Dryopteridaceae (40—45/1700) EUPHYLLOPHYTA Lygodiaceae (1/25) Lindsaeaceae (8/200) MONILOPHYTA Schizaeaceae (2/30) Lomariopsidaceae (4/70) EQifiSETOPSIDA Salviniales Oleandraceae (1/40) Equisetaceae (1/15) Marsileaceae (3/75) Onocleaceae (4/5) PSILOTOPSIDA Salviniaceae (2/16) Polypodiaceae (56/1200) Ophioglossaceae (4/55—80) Cyatheales Pteridaceae (50/950) Psilotaceae (2/17) Cibotiaceae (1/11) Saccolomataceae (1/12) MARATTIOPSIDA Culcitaceae (1/2) Tectariaceae (3—15/230) Marattiaceae (6/80) Cyatheaceae (4/600+) Thelypteridaceae (5—30/950) POLYPODIOPSIDA Dicksoniaceae (3/30) Woodsiaceae (15/700) Osmundales Loxomataceae (2/2) central vascular cylinder Osmundaceae (3/20) Metaxyaceae (1/2) SPERMATOPHYTA (See Chapter 5) Hymenophyllales Plagiogyriaceae (1/15) FIGURE 4.9 Anatomy of the root, an apomorphy of the vascular plants. A. Root whole mount. B. Root longitudinal-section. C. Whole Hymenophyllaceae (9/600) Thyrsopteridaceae (1/1) root cross-section. D. Close-up of central vascular cylinder, showing tissues. TABLE 4.1 Taxonomic groups of Tracheophyta, vascular plants (minus those of Spermatophyta, seed plants). Classes, orders, and family names after Smith et al. (2006). Higher groups (traditionally treated as phyla) after Cantino et al. (2007). Families in bold are described in found today in the Selaginellaceae of the lycophytes and all the pericycle or endodermis. Lateral roots penetrate the tis detail.
    [Show full text]
  • Reproductive Morphology
    Week 3; Wednesday Announcements: 1st lab quiz TODAY Reproductive Morphology Reproductive morphology - any portion of a plant that is involved with or a direct product of sexual reproduction Example: cones, flowers, fruits, seeds, etc. Basic Plant Life cycle Our view of the importance of gametes in the life cycle is shaped by the animal life cycle in which meiosis (the cell division creating haploid daughter cells with only one set of chromosomes) gives rise directly to sperm and eggs which are one celled and do not live independently. Fertilization (or the fusion of gametes – sperm and egg) occurs inside the animal to recreate the diploid organism (2 sets of chromosomes). Therefore, this life cycle is dominated by the diploid generation. This is NOT necessarily the case among plants! Generalized life cycle -overhead- - alternation of generations – In plants, spores are the result of meiosis. These may grow into a multicellular, independent organism (gametophyte – “gamete-bearer”), which eventually produces sperm and eggs (gametes). These fuse (fertilization) and a zygote is formed which grows into what is known as a sporophyte - “spore-bearer”. (In seed plants, pollination must occur before fertilization! ) This sporophyte produces structures called sporangia in which meiosis occurs and the spores are released. Spores (the product of meiosis) are the first cell of the gametophyte generation. Distinguish Pollination from Fertilization and Spore from Gamete Pollination – the act of transferring pollen from anther or male cone to stigma or female cone; restricted to seed plants. Fertilization – the act of fusion between sperm and egg – must follow pollination in seed plants; fertilization occurs in all sexually reproducing organisms.
    [Show full text]
  • Seedless Plants 14.3: Seed Plants: Gymnosperms 14.4: Seed Plants: Angiosperms
    Concepts of Biology Chapter 14 | Diversity of Plants 325 14 | DIVERSITY OF PLANTS Figure 14.1 Plants dominate the landscape and play an integral role in human societies. (a) Palm trees grow in tropical or subtropical climates; (b) wheat is a crop in most of the world; the flower of (c) the cotton plant produces fibers that are woven into fabric; the potent alkaloids of (d) the beautiful opium poppy have influenced human life both as a medicinal remedy and as a dangerously addictive drug. (credit a: modification of work by “3BoysInSanDiego”/Wikimedia Commons”; credit b: modification of work by Stephen Ausmus, USDA ARS; credit c: modification of work by David Nance, USDA ARS; credit d: modification of work by Jolly Janner) Chapter Outline 14.1: The Plant Kingdom 14.2: Seedless Plants 14.3: Seed Plants: Gymnosperms 14.4: Seed Plants: Angiosperms Introduction Plants play an integral role in all aspects of life on the planet, shaping the physical terrain, influencing the climate, and maintaining life as we know it. For millennia, human societies have depended on plants for nutrition and medicinal compounds, and for many industrial by-products, such as timber, paper, dyes, and textiles. Palms provide materials 326 Chapter 14 | Diversity of Plants including rattans, oils, and dates. Wheat is grown to feed both human and animal populations. The cotton boll flower is harvested and its fibers transformed into clothing or pulp for paper. The showy opium poppy is valued both as an ornamental flower and as a source of potent opiate compounds. Current evolutionary thought holds that all plants are monophyletic: that is, descendants of a single common ancestor.
    [Show full text]
  • UNIT-PTERIDOPHYTA (BOT-502).Pdf
    COURSE NAME-BIOLOGY AND DIVERSITY OF ALGAE, BRYOPHYTA AND PTERIDOPHYTA (Paper Code: BOT 502) UNIT–16 : GENERAL CHARACTERS AND CLASSIFICATION OF PTERIDOPHYTES Dr. Pooja Juyal Department of Botany Uttarakhand Open University, Haldwani Email id: [email protected] CONTENT • INTRODUCTION • GENERAL CHARACTERISTICS • HABITAT • CLASSIFICATION • REPRODUCTION • ALTERNATION OF GENERATION • ECONOMIC IMPORTANCE INTRODUCTION The word Pteridophyta has Greek origin. Pteron means a “feather” and Phyton means plants. The plants of this group have feather like fronds (ferns). The group of pteridophyta included into Cryptogams with algae, fungi and Bryophytes. The algae, fungi and bryophytes are called lower cryptogames while the Pteidophytes are called higher cryptogams. Pteridophytes also called Vascular cryptogames, because only pteridophytes have well developed conducting system among cryptogams. Due to this reason they are the first true land plants. All cryptogams reproduce by means of spores and do not produce seeds. The Peridophytes are assemblage of flowerless, seedless, spore bearing vascular plants, that have successfully invaded the land. Pteridophytes have a long fossil history on our planet. They are known from as far back as 380 million years. Fossils of pteridophytes have been obtained from rock strata belonging to Silurian and Devonian periods of the Palaeozoic era. So the Palaeozoic era sometimes also called the “The age of pteridophyta”. The fossil Pteridophytes were herbaceous as well as arborescent. The tree ferns, giant horse tails and arborescent lycopods dominated the swampy landscapes of the ancient age. The present day lycopods are the mere relicts the Lepidodendron like fossil arborescent lycopods. Only present day ferns have nearby stature of their ancestors. Psilotum and Tmesipteris are two surviving remains of psilopsids, conserve the primitive features of the first land plants.
    [Show full text]
  • ® General Characters:- ® the Spermatophytes (Also Known As
    General Characters:- The spermatophytes (also known as phanerogams) comprise those plants that produce seeds. They are a subset of the embryophytes or land plants. The living spermatophytes include five groups: 1. Cycadophyta: a subtropical and tropical group of plants with a large crown of pinnate compound leaves and a stout trunk. They look like palms. 2. Ginkgophyta: represented by a single living species of trees (Ginkgo biloba). 3. Coniferophyta: cone-bearing trees and shrubs such as Pinus. 4. Gnetophyta: woody plants; represented by the genera Gnetum, Welwitschia, and Ephedra. 5. Angiosperms: the flowering plants, a large group including many familiar plants (both monocotyledons and dicotyledons) in a wide variety of habitats. The first four groups are collectively known as Gymnosperms (non-flowering seed plants, or naked-seed plants). In addition to the groups listed above, the fossil record contains evidence of many extinct species of seed plants. The so-called "seed ferns" (Pteridospermae) were one of the earliest successful groups of land plants; and forests dominated by seed ferns were prevalent in the ancient ages. In the recent ages, seed ferns had declined and representatives of modern gymnosperm groups were abundant and dominant. B A C D Gymnosperms:(A) Ginkgo biloba, (B) Cycas, (C) Welwtschia, (D) Ephedra Morphological studies have shown a close relationship between the gnetophytes and the angiosperms; both groups contain xylem vessels and sieve tubes as the tracheary elements. In the lower vascular plants xylem is represented by tracheids and phloem by sieve cells. General Characters:- 1- Gymnosperms (Gymnospermae) are a group of spermatophytes (seed-bearing plants) with ovules being carried on the edge of open sporophylls, which are usually arranged in cone-like structures.
    [Show full text]
  • Seedless Plants
    702 Chapter 25 | Seedless Plants 25.1 | Early Plant Life By the end of this section, you will be able to do the following: • Discuss the challenges to plant life on land • Describe the adaptations that allowed plants to colonize the land • Describe the timeline of plant evolution and the impact of land plants on other living things The kingdom Plantae constitutes large and varied groups of organisms. There are more than 300,000 species of catalogued plants. Of these, more than 260,000 are seed plants. Mosses, ferns, conifers, and flowering plants are all members of the plant kingdom. Land plants arose within the Archaeplastida, which includes the red algae (Rhodophyta) and two groups of green algae, Chlorophyta and Charaphyta. Most biologists also consider at least some green algae to be plants, although others exclude all algae from the plant kingdom. The reason for this disagreement stems from the fact that only green algae, the Chlorophytes and Charophytes, share common characteristics with land plants (such as using chlorophyll a and b plus carotene in the same proportion as plants). These characteristics are absent from other types of algae. Algae and Evolutionary Paths to Photosynthesis Some scientists consider all algae to be plants, while others assert that only the green algae belong in the kingdom Plantae. Still others include only the Charophytes among the plants. These divergent opinions are related to the different evolutionary paths to photosynthesis selected for in different types of algae. While all algae are photosynthetic—that is, they contain some form of a chloroplast—they didn’t all become photosynthetic via the same path.
    [Show full text]
  • L14 Ferns & Allies (Lecture Slides)
    3/22/20 I. Intro to "Ferns & Fern Allies" A. Types L14: Ferns & Fern Allies BIOL 153/L Black Hills State Univ. Ramseys 1. Lycophytes 1. Lycophytes short w/ microphylls + strobili; • Club moss: resemble tiny conifers (strobilus = club) gametophytes photosynthetic, or not; oldest vascular lineage • Spike moss: mostly tropical; some from dry places widespread, not diverse Club moss Spike moss 1 3/22/20 2. Ferns many sporophyte forms; heart-shaped gametophyte; frond from rhizome widespread, diverse Ferns 3. Horsetails Horsetails jointed stem with silica; tiny whorled leaves; stems branched or naked Northern Hemisphere, not diverse I. Intro to "Ferns & Fern Allies" Red Algae B. Evolutionary relationships "Green Algae" "Bryophytes" "Ferns Land & Fern Allies" Plants Gymnosperms & Angiosperms 2 3/22/20 Clubmoss I. Intro to "Ferns & Fern Allies" Spike moss C. Dominance of sporophyte Ferns Horsetails largest, most persistent stage is sporophyte I. Intro to "Ferns & Fern Allies" I. Intro to "Ferns & Fern Allies" C. Dominance of sporophyte D. Life in terrestrial environment 1. Adaptations present 1. Adaptations present embryo + stomata vascular tissue + roots embryo + stomata vascular tissue + roots (sporophyte only) (sporophyte only) 2. Adaptations absent wood, pollen, seeds flowers + fruits 3 3/22/20 1. Homosporous vs. heterosporous 1. Homosporous vs. heterosporous homosporous: producing one type of spore homosporous: producing one type of spore gametophyte bisexual gametophyte bisexual heterosporous: producing two types of spores gametophyte male or female II. Structures and terminology 2. Spore vs. microspore/megaspore A. Reproductive spores are produced by.... homosporous plants 2. Spore vs. microspore/megaspore 3. Sporangia and sporophyll spores are produced by.... sporangia: structures in which spores produced homosporous plants microspores and megaspores are produced by..
    [Show full text]
  • Reproductive Morphology of Lycopodium and Selaginella I
    12 Laboratory 6 - Reproductive Morphology of Lycopodium and Selaginella I. Lycopodium A. Morphology of Lycopodium strobili and subgenera 1. Subgenus Huperzia (old Urostachya) Observe herbarium and preserved specimens of the following species of Lycopodium, subgenus Huperzia (ref. Gifford and Foster, p. 123), as available: Lycopodium lucidulum L. selago L. reflexum L. alopecuroides All of these species show strobili which are not compact and merely represent fertile areas of the stem. Arrange these specimens in typological order, if possible, starting with the least specialized strobilar organization and proceeding to the most specialized. What vegetative features do these urostachyoid Lycopodium types have in common? Obtain pickled material of L. lucidulum if fresh strobili are not available. Locate the sporangium, the sporophyll and the shoot apex. Is a ligule present? Obtain and observe a prepared slide of the strobilus of L. lucidulum or L. selago. Describe the shape of the sporangium. Is the sporangium located on a stalk? Is the line of dehiscence obvious? Is it longitudinal or transverse? Carefully remove a single sporophyll from a plant and observe it under the dissecting microscope. Is the morphology of the sporophyll the same as that of a vegetative leaf? Is the phyllotaxis of the sporophylls similar to that of the vegetative leaf? Is the genus Lycopodium heterosporous or homosporous? 2. Subgenera Lycopodium, Diphasiastrum and Lycopodiella (old Rhopalostachya) Observe herbarium and preserved specimens of the following species of Lycopodium as available: L. annotinum L. cernuum L. clavatum L. complanatum L. inundatum L. obscurum L. pachystachyon These species exhibit strobili which are very distinct and not merely fertile, little-differentiated areas of the shoot.
    [Show full text]
  • Chapter 12 Biology of Non-Flowering Plants
    BOT 3015L (Outlaw/Sherdan/Aghoram); Page 1 of 8 Chapter 12 Biology of Non-Flowering Plants Objectives Overview of Non-Flowering Plants. Know the distinguishing characteristics of plants. Know the plant adaptations required for terrestrial life. Know the adaptations for terrestrial life displayed by angiosperms and how they are advantageous. Bryophytes. Distinguish bryophytes from green algae1 and from other plants. Understand the life cycle of Marchantia, a liverwort, and how it compares with the life cycle of higher plants e.g. gymnosperms and angiosperms. Know the structures of the bryophyte gametophyte and sporophyte and understand their function. Know the characteristics of peat moss. Seedless Vascular Plants. Understand the advantages of a vascular system for terrestrial life. Understand the limitations associated with not having a seed. Understand how homosporous and heterosporous life cycles differ. Gymnosperms. Know general features of gymnosperms. Understand the advantages of seeds and pollen for terrestrial life. Know the life cycle of gymnosperms. Understand how the structure of a gymnosperm leaf is adapted for terrestrial habitats. Comparing Angiosperm and Gymnosperm Reproduction. Understand the similarities and differences in reproduction of angiosperms and gymnosperms. Understand the differences in seed formation in gymnosperms and angiosperms. Understand the advantages that each has over the other in terrestrial habitats. Introduction to Non-flowering Plants Several lines of evidence indicate that plants (embryophytes) evolved from green algae. Plants, unlike green algae, are, in general, terrestrial and have evolved adaptations for terrestrial life. Terrestrial plants require adaptations to avoid desiccation, provide mechanical support, transport water and nutrients, transfer “male” gametes, and protect the zygote from desiccation and harsh conditions.
    [Show full text]