DOCSLIB.ORG

Chapter 22 the Land Plants

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Chapter 22 the Land Plants Chapter 22 The Land Plants © Cengage Learning 2016 22.2 Plant Ancestry and Diversity • Plants – Multicelled – Photosynthetic eukaryotes – Adapted to life on land – Close relatives of red algae and green algae – Contain cellulose cell walls and chloroplasts • Chlorophylls a and b – Embryophytes • Embryos form within chamber of parental tissues • Receive nourishment during development © Cengage Learning 2016 Plant Ancestry and Diversity • Adaptive radiation • First plants evolved 500 million years ago – Photosynthetic cells had released oxygen into the atmosphere and ozone layer had formed • Plant spore © Cengage Learning 2016 Plant Ancestry and Diversity • Plant spore – Haploid cell with a cell wall • Some plants have alternating generations – A life cycle in which a diploid generation alternates with a haploid one – Diploid – Haploid © Cengage Learning 2016 multicelled mitosis sporophyte zygote Diploid (2n) Phase of Cycle Fertilization Meiosis Haploid (n) gametes Phase of Cycle spores multicelled gametophyte Stepped Art © Cengage Learning 2016 Major groups of plants • Criteria – Vascular – Seed production – Types of seeds produced – Development and morphology © Cengage Learning 2016 © Cengage Learning 2016 Evolutionary Trends Among Plants • Story of plant evolution – Adapted to life on land – Adapted to increasingly drier habitats • Sporophyte dominates all vascular plant life cycles – Spores more likely to survive in dry conditions • Oak tree – Large and complex sporophyte – Gametophyte: only a few cells © Cengage Learning 2016 Evolutionary Trends Among Plants • Genetic factors – Influenced sporophyte dominance • Structural adaptations – Cuticle • Helps reduce evaporative water loss – Stomata • Open to allow gas exchange for photosynthesis • Close to conserve water © Cengage Learning 2016 Evolutionary Trends Among Plants • Vascular tissues – Internal system of pipelines – Xylem distributes water – Phloem distributes sugars – Lignin provides structural support • Leaves – Contain veins of vascular tissue – Allow plant to capture sunlight and exchange gases © Cengage Learning 2016 Pollen and Seeds • Pollen grains – Walled, immature gametophyte • Gives rise to male gametes – Released by seed-bearing vascular plants – Travel to female gametophytes on the wind or in insect bodies – Allow plants to reproduce even in dry environments © Cengage Learning 2016 Pollen and Seeds • Seeds – Consist of an embryo sporophyte and nutritive tissue enclosed within a waterproof seed coat – Many have features that facilitate their dispersal • Angiosperms disperse seeds inside a fruit © Cengage Learning 2016 Bryophytes • Mosses – Most diverse and familiar group of bryophytes – Example: Sphagnum (peat moss) • 350 species • One of the most economically important bryophytes • Grow in peat bogs in high latitude regions of Europe, Asia, and North America • Blocks are cut, dried, and burned as fuel in Ireland • Helps soil retain moisture © Cengage Learning 2016 7 2 zygote sporophyte (2 n) Diploid (2n) phase Fertilization Meiosis Haploid ( n) 6 phase 3 1 gametophyte (n) ① The leafy green part of a moss is the sperm released from spor e (n) released haploid gametophyte. male gametangium from sporangium ② The diploid sporophyte has a stalk and a male capsule (sporangium). It is not gametophyte photosynthetic. ③ Haploid spores form by meiosis in the capsule, are released, and drift with the 4 winds. sperm ④ Spores germinate and develop into male female or female gametophytes with 5 gametophyte gametangia that produce eggs or sperm by mitosis. ⑤ Sperm swim to eggs. ⑥ Fertilization produces a zygote. egg in female ⑦ The zygote grows and develops into a gametangium new sporophyte while remaining attached to and nourished by the female © 2016 Cengage Learning gametophyte. Jane Burton/ Bruce Coleman Ltd. © Cengage Learning 2016 Bryophytes • Liverworts – Among oldest known fossils of land plants – Some gametophytes look leafy and others are flat sheets – Example: Marchantia • Hornworts – Has a pointy, hornlike sporophyte – Spores form in upright capsule called sporangium – Contain chloroplasts © Cengage Learning 2016 Seedless Vascular Plants • Oldest vascular plant lineages • Have flagellated sperm that swim to eggs • Disperse by releasing spores directly to the environment • Two lineages survive today – Lycophytes – Monilophytes © Cengage Learning 2016 Seedless Vascular Plants • Club mosses – Often grow on floor of temperate forests • Whisk ferns and horsetails – Native to the Southeastern United States – Includes rushes • Ferns – Most diverse and familiar seedless vascular plant – Most live in the tropics © Cengage Learning 2016 1 mature sporophyte 5 young sporophyte 1 The familiar leafy form is the diploid sporophyte. 2 Meiosis in cells on the underside of fronds (leaves) produces haploid spores. zygote 3 After spores are released, they germinate and grow into tiny gametophytes that sori (clusters of sporangia) produce eggs and sperm. rhizome on underside of frond 2 Sperm swim to eggs and 4 Diploid (2n) phase fertilize them, forming a Fertilization Meiosis zygote. Haploid ( n) phase egg 5 The sporophyte begins its 4 development attached to the gametophyte, but it continues to grow and live independently female mature spore after the gametophyte dies. gametangium gametophyte (underside) male gametangium 3 sperm photo, A. & E. Bomford/ Ardea, London; art, © 2016 Cengage Learning © Cengage Learning 2016 Rise of the Seed Plants • Advantages of seed-bearing plants – Reproductive traits – Structural traits © Cengage Learning 2016 pollen sac (2n) ovule (2n) meiosis meiosis microspores (n) in pollen sac megaspores (n) in ovule develop into develop into sperm-producing male gametophytes (pollen grains) egg-bearing female release and pollination gametophytes in ovule delivers sperm to fertilization zygote (2n) in ovule develop into seed (embryo sporophyte in ovule) Stepped Art © Cengage Learning 2016 Figure 22.21 p365 Gymnosperms • Vascular seed plants – Produce seeds on the surface of ovules – Some seeds enclosed in a fleshy or papery covering • Types – Conifers – Cycads – Ginkgos – Gnetophytes © Cengage Learning 2016 Gymnosperms • Conifers – 600 species – Trees and shrubs with woody cones – Needle-like or scale-like leaves with a thick cuticle – More resistant to drought and cold than flowering plants – Evergreen – Include the longest lived plants • Some bristlecone pines are 4,000 years old © Cengage Learning 2016 One scale sectioned One scale sectioned through ovule through pollen sac 1 Scales of pollen 4 Scales of cones hold pollen ovulate cones sacs. contain ovules . pollen cone with ovulate cone with many scales many scales sporophyte (2n) Meiosis Meiosis 9 The seed seed coat germinates and embryo grows into a new seed sporophyte. stored food 2 Meiosis of cells in 5 Meiosis of cells pollen sacs yields in ovules yields microspores ( n). megaspores ( n). 8 Fertilization produces a zygote zygote (2 n) that develops into a seed. Fer tilization Inside 3 Microspores 6 Megaspores ovule develop into pollen develop into egg- grains (male game- bearing female tophytes) that are pollen tube eggs (n) gametophyte s released and travel inside the ovule. on the wind. female sperm (n) gametophyte 7 A pollen grain alights on a scale of an ovulate cone. It germinates and a pollen tube grows toward the ovule. Sperm form as the tube grows. © 2016 Cengage Learning; photos, Robert & Linda Mitchell Photography; Robert Potts, California Academy of Sciences; R. J. Erwin/Science Source © Cengage Learning 2016 Gymnosperms • Cycads – Native to dry tropics and subtropics • Ginkgos – One species remains today: Ginkgo biloba • Native to China – Deciduous • Gnetophytes – Tropical trees – Desert shrubs – Leathery vines © Cengage Learning 2016 Angiosperms – The Flowering Plants • Vascular seed plants that make flowers and fruits • Flower – Specialized reproductive shoot – Contain sepals, petals, and stamen – Innermost part of the flower is the ovary – After fertilization, ovule matures into seed • Ovary becomes the fruit © Cengage Learning 2016 1 An anther has two pollen sacs pollen sac with diploid cells of anther that give rise to (cutaway ovule microspores. view) 4 An ovule forms on the ovary wall. It contains a diploid 2n cell that will undergo meiosis. 9 The ovule seed coat (2n) develops into seed Meiosis embryo (2 n) Meiosis a seed. endosperm (3 n) Double Fertilization 2 Meiosis produces microspores (n) microspores. 5 Meiosis megaspores (n) yields four megaspores. Microspores 3 pollen grain(n) Three will develop into pollen degenerate. grains (male gametophytes). mature female gametophyte in ovule pollination pollen tube 6 The remaining delivers megaspore devel- 2 sperm to cell with ops into a female 7 Pollinatio n ovule 2 nuclei gametophyte tha t occurs, and the pollen consists of an egg grain germinates. pollen and six other cells, mature male A pollen tube grows to tube egg including a cell wit h and through ovary gametophyte sperm 8 During double fertilization, one two nuclei. tissue to the ovule, sperm fertilizes the egg to form a where it releases two zygote; the other fertilizes the cell with © 2016 Cengage Learning sperm. two nuclei to form a triploid (3n) cell. © Cengage Learning 2016 Angiosperms – The Flowering Plants • 90 percent of all species today are angiosperms • Angiosperm characteristics that give them a selective advantage over gymnosperms – Shorter life cycle – Animal-pollinated flowers – Enhanced seed dispersal © Cengage Learning 2016 Angiosperm Diversity and Importance © Cengage Learning 2016.
Load more

Recommended publications
  • Fungi-Rhizopus
    Characters of Fungi Some of the most important characters of fungi are as follows: 1. Occurrence 2. Thallus organization 3. Different forms of mycelium 4. Cell structure 5. Nutrition 6. Heterothallism and Homothallism 7. Reproduction 8. Classification of Fungi. 1. Occurrence: Fungi are cosmopolitan and occur in air, water soil and on plants and animals. They prefer to grow in warm and humid places. Hence, we keep food in the refrigerator to prevent bacterial and fungal infestation. 2. Thallus organization: Except some unicellular forms (e.g. yeasts, Synchytrium), the fungal body is a thallus called mycelium. The mycelium is an interwoven mass of thread-like hyphae (Sing, hypha). Hyphae may be septate (with cross wall) and aseptate (without cross wall). Some fungi are dimorphic that found as both unicellular and mycelial forms e.g. Candida albicans. 3. Different forms of mycelium: (a) Plectenchyma (fungal tissue): In a fungal mycelium, hyphae organized loosely or compactly woven to form a tissue called plectenchyma. It is two types: i. Prosenchyma or Prosoplectenchyma: In these fungal tissue hyphae are loosely interwoven lying more or less parallel to each other. ii. Pseudoparenchyma or paraplectenchyma: In these fungal tissue hyphae are compactly interwoven looking like a parenchyma in cross-section. (b) Sclerotia (Gr. Skleros=haid): These are hard dormant bodies consist of compact hyphae protected by external thickened hyphae. Each Sclerotium germinates into a mycelium, on return of favourable condition, e.g., Penicillium. (c) Rhizomorphs: They are root-like compactly interwoven hyphae with distinct growing tip. They help in absorption and perennation (to tide over the unfavourable periods), e.g., Armillaria mellea.
    [Show full text]
  • Anthocerotophyta
    Glime, J. M. 2017. Anthocerotophyta. Chapt. 2-8. In: Glime, J. M. Bryophyte Ecology. Volume 1. Physiological Ecology. Ebook 2-8-1 sponsored by Michigan Technological University and the International Association of Bryologists. Last updated 5 June 2020 and available at <http://digitalcommons.mtu.edu/bryophyte-ecology/>. CHAPTER 2-8 ANTHOCEROTOPHYTA TABLE OF CONTENTS Anthocerotophyta ......................................................................................................................................... 2-8-2 Summary .................................................................................................................................................... 2-8-10 Acknowledgments ...................................................................................................................................... 2-8-10 Literature Cited .......................................................................................................................................... 2-8-10 2-8-2 Chapter 2-8: Anthocerotophyta CHAPTER 2-8 ANTHOCEROTOPHYTA Figure 1. Notothylas orbicularis thallus with involucres. Photo by Michael Lüth, with permission. Anthocerotophyta These plants, once placed among the bryophytes in the families. The second class is Leiosporocerotopsida, a Anthocerotae, now generally placed in the phylum class with one order, one family, and one genus. The genus Anthocerotophyta (hornworts, Figure 1), seem more Leiosporoceros differs from members of the class distantly related, and genetic evidence may even present
    [Show full text]
  • Classifications of Fungi
    Chapter 24 | Fungi 675 Sexual Reproduction Sexual reproduction introduces genetic variation into a population of fungi. In fungi, sexual reproduction often occurs in response to adverse environmental conditions. During sexual reproduction, two mating types are produced. When both mating types are present in the same mycelium, it is called homothallic, or self-fertile. Heterothallic mycelia require two different, but compatible, mycelia to reproduce sexually. Although there are many variations in fungal sexual reproduction, all include the following three stages (Figure 24.8). First, during plasmogamy (literally, “marriage or union of cytoplasm”), two haploid cells fuse, leading to a dikaryotic stage where two haploid nuclei coexist in a single cell. During karyogamy (“nuclear marriage”), the haploid nuclei fuse to form a diploid zygote nucleus. Finally, meiosis takes place in the gametangia (singular, gametangium) organs, in which gametes of different mating types are generated. At this stage, spores are disseminated into the environment. Review the characteristics of fungi by visiting this interactive site (http://openstaxcollege.org/l/ fungi_kingdom) from Wisconsin-online. 24.2 | Classifications of Fungi By the end of this section, you will be able to do the following: • Identify fungi and place them into the five major phyla according to current classification • Describe each phylum in terms of major representative species and patterns of reproduction The kingdom Fungi contains five major phyla that were established according to their mode of sexual reproduction or using molecular data. Polyphyletic, unrelated fungi that reproduce without a sexual cycle, were once placed for convenience in a sixth group, the Deuteromycota, called a “form phylum,” because superficially they appeared to be similar.
    [Show full text]
  • Seedless Plants Key Concept Seedless Plants Do Not Produce Seeds 2 but Are Well Adapted for Reproduction and Survival
    Seedless Plants Key Concept Seedless plants do not produce seeds 2 but are well adapted for reproduction and survival. What You Will Learn When you think of plants, you probably think of plants, • Nonvascular plants do not have such as trees and flowers, that make seeds. But two groups of specialized vascular tissues. plants don’t make seeds. The two groups of seedless plants are • Seedless vascular plants have specialized vascular tissues. nonvascular plants and seedless vascular plants. • Seedless plants reproduce sexually and asexually, but they need water Nonvascular Plants to reproduce. Mosses, liverworts, and hornworts do not have vascular • Seedless plants have two stages tissue to transport water and nutrients. Each cell of the plant in their life cycle. must get water from the environment or from a nearby cell. So, Why It Matters nonvascular plants usually live in places that are damp. Also, Seedless plants play many roles in nonvascular plants are small. They grow on soil, the bark of the environment, including helping to form soil and preventing erosion. trees, and rocks. Mosses, liverworts, and hornworts don’t have true stems, roots, or leaves. They do, however, have structures Vocabulary that carry out the activities of stems, roots, and leaves. • rhizoid • rhizome Mosses Large groups of mosses cover soil or rocks with a mat of Graphic Organizer In your Science tiny green plants. Mosses have leafy stalks and rhizoids. A Journal, create a Venn Diagram that rhizoid is a rootlike structure that holds nonvascular plants in compares vascular plants and nonvas- place. Rhizoids help the plants get water and nutrients.
    [Show full text]
  • Crosstalk Between Sporophyte and Gametophyte Generations Is Promoted By
    Genetics: Early Online, published on April 13, 2016 as 10.1534/genetics.115.180141 Crosstalk between Sporophyte and Gametophyte Generations Is Promoted by CHD3 Chromatin Remodelers in A. thaliana Benjamin Carter*, James T. Henderson*, Elisabeth Svedin§, Martijn Fiers†, Kyle McCarthy*, Amanda Smith*, Changhua Guo†, Brett Bishop*, Heng Zhang*, Tjitske Riksen†, Allison Shockley*, Brian P. Dilkes§, Kim Boutilier†, Joe Ogas* * Department of Biochemistry, Purdue University, West Lafayette, Indiana § Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana † Bioscience, Wageningen University and Research Centre, Wageningen, Netherlands 1 Copyright 2016. CHD3 Remodelers in Reproductive Development Keywords: PICKLE, PKR2, ovule, pollen tube, seed size Corresponding author: Joe Ogas 175 S. University St. West Lafayette, IN 47907 765-496-3969 [email protected] 2 ABSTRACT Angiosperm reproduction requires the integrated development of multiple tissues with different genotypes. To achieve successful fertilization, the haploid female gametophytes and diploid ovary must coordinate their development, after which the male gametes must navigate through the maternal sporophytic tissues to reach the female gametes. After fertilization, seed development requires coordinated development of the maternal diploid integuments, the triploid endosperm, and the diploid zygote. Transcription and signaling factors contribute to communication between these tissues, and roles for epigenetic regulation have been described for some of these processes. Here we identify a broad role for CHD3 chromatin remodelers in Arabidopsis thaliana reproductive development. Plants lacking the CHD3 remodeler PICKLE exhibit various reproductive defects including abnormal development of the integuments, female gametophyte, and pollen tube as well as delayed progression of ovule and embryo development. Genetic analyses demonstrate that these phenotypes result from loss of PICKLE in the maternal sporophyte.
    [Show full text]
  • 16. Plants.Pptx
    2/27/11 Class announcements Simulation #3-#5 – Class results 1. Next Friday – HW5. Diffusion homework due. Available at GAE homeworks link 2. Next Friday’s GAE – bring 2 calculators for each circle 4 group. Particles past Concentration gradient = ΔC (Particle number) Δx (Distance of 4 circles) Fick’s First Law of Diffusion Simulation #6 – Class results ΔC area J = -D J Δx Not enough Δx e.g., a membrane data for 80 s J = flux (“diffusion rate”) D = diffusion coefficient ΔC = concentration difference Δx = distance € (Negative sign means down the gradient, but biologists often drop Two (of many) possibilities include: the sign.) 1) t is directly proportional to x (the plot of t vs. x is a straight line) 2) t is directly proportional to x squared (the plot is parabolic) 1 2/27/11 Movement of small diffusible molecules 2 Fick’s Second Law of Diffusion For example, glucose - 2 ∂C ∂ C ( x) = D molecular weight: 180 Da Δ 2 t = t x -6 2 ∂ ∂ diffusion coefficient: 7.0 x 10 cm /sec 2D Einstein’s solution - “time-to-diffuse equation” Distance (Δx) Time (t) Typical Structure 10 nm 100 ns Cell membrane 2 (Δx) 1 µm 1 ms Bacteria € t = 10 µm 100 ms€ Eukaryotic cell HELP ME, 2D 207! 300 µm 1.5 min Sea urchin embryo t = time 1 mm 16.6 min Volvox Δx = mean distance traveled D = diffusion coefficient 2 cm 4.6 days Human heart wall 10 cm 82.7 days Squid giant axon Adapted from www.npl.co.uk/educate-+-explore/beginners-guides-posters/einstein-and-blackboard€ The Evolution of Plants - They Made the Land Green The “easy” life of an aquatic alga • Bathed in nutrients
    [Show full text]
  • Mosses and Ferns
    Mosses and Ferns • How did they evolve from Protists? Moss and Fern Life Cycles Group 1: Seedless, Nonvascular Plants • Live in moist environments to reproduce • Grow low to ground to retain moisture (nonvascular) • Lack true leaves • Common pioneer species during succession • Gametophyte most common (dominant) • Ex: Mosses, liverworts, hornworts Moss Life Cycle 1)Moss 2) Through water, 3) Diploid sporophyte 4) Sporophyte will gametophytes sperm from the male will grow from zygote create and release grow near the gametophyte will haploid spores ground swim to the female (haploid stage) gametophyte to create a diploid zygote Diploid sporophyte . zygo egg zygo te egg te zygo zygo egg egg te te male male female female female male female male Haploid gametophytes 5) Haploid 6) The process spores land repeats and grow into new . gametophytes . Haploid gametophytesground . sporophyte . zygo egg zygo te egg te zygo zygo egg egg te te male male female female female male female male Haploid gametophytes • Vascular system allows Group 2: Seedless, – Taller growth – Nutrient transportation Vascular Plants • Live in moist environments – swimming sperm • Gametophyte stage – Male gametophyte: makes sperm – Female gametophyte: makes eggs – Sperm swims to fertilize eggs • Sporophyte stage – Spores released into air – Spores land and grow into gametophyte • Ex: Ferns, Club mosses, Horsetails Fern Life Cycle 1) Sporophyte creates and releases haploid spores Adult Sporophyte . ground 2) Haploid spores land in the soil . ground 3) From the haploid spores, gametophyte grows in the soil Let’s zoom in Fern gametophytes are called a prothallus ground 4) Sperm swim through water from the male parts (antheridium) to the female parts (archegonia)…zygote created Let’s zoom back out zygo zygo egg egg te te zygo egg te 5) Diploid sporophyte grows from the zygote sporophyte Fern gametophytes are called a prothallus ground 6) Fiddle head uncurls….fronds open up 7) Cycle repeats -- Haploid spores created and released .
    [Show full text]
  • Evidence for Equal Size Cell Divisions During Gametogenesis in a Marine Green Alga Monostroma Angicava
    www.nature.com/scientificreports OPEN Evidence for equal size cell divisions during gametogenesis in a marine green alga Monostroma Received: 18 March 2015 Accepted: 03 August 2015 angicava Published: 03 September 2015 Tatsuya Togashi1, Yusuke Horinouchi1, Hironobu Sasaki2 & Jin Yoshimura1,3,4 In cell divisions, relative size of daughter cells should play fundamental roles in gametogenesis and embryogenesis. Differences in gamete size between the two mating types underlie sexual selection. Size of daughter cells is a key factor to regulate cell divisions during cleavage. In cleavage, the form of cell divisions (equal/unequal in size) determines the developmental fate of each blastomere. However, strict validation of the form of cell divisions is rarely demonstrated. We cannot distinguish between equal and unequal cell divisions by analysing only the mean size of daughter cells, because their means can be the same. In contrast, the dispersion of daughter cell size depends on the forms of cell divisions. Based on this, we show that gametogenesis in the marine green alga, Monostroma angicava, exhibits equal size cell divisions. The variance and the mean of gamete size (volume) of each mating type measured agree closely with the prediction from synchronized equal size cell divisions. Gamete size actually takes only discrete values here. This is a key theoretical assumption made to explain the diversified evolution of isogamy and anisogamy in marine green algae. Our results suggest that germ cells adopt equal size cell divisions during gametogenesis. Differences in sperm and egg size are evident in many animals and land plants1. However, variable mat- ing systems are also found in green algal taxa: 1) isogamy, where gamete sizes are identical between the two mating types, 2) slight anisogamy, where the sizes of male and female gametes are slightly different, and 3) marked anisogamy, where their sizes are markedly different2,3.
    [Show full text]
  • Evolution of the Two Sexes Under Internal Fertilization and Alternative Evolutionary Pathways
    vol. 193, no. 5 the american naturalist may 2019 Evolution of the Two Sexes under Internal Fertilization and Alternative Evolutionary Pathways Jussi Lehtonen1,* and Geoff A. Parker2 1. School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, 2006 New South Wales, Australia; and Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052 New South Wales, Australia; 2. Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom Submitted September 8, 2018; Accepted November 30, 2018; Electronically published March 18, 2019 Online enhancements: supplemental material. abstract: ogy. It generates the two sexes, males and females, and sexual Transition from isogamy to anisogamy, hence males and fl females, leads to sexual selection, sexual conflict, sexual dimorphism, selection and sexual con ict develop from it (Darwin 1871; and sex roles. Gamete dynamics theory links biophysics of gamete Bateman 1948; Parker et al. 1972; Togashi and Cox 2011; limitation, gamete competition, and resource requirements for zygote Parker 2014; Lehtonen et al. 2016; Hanschen et al. 2018). survival and assumes broadcast spawning. It makes testable predic- The volvocine green algae are classically the group used to tions, but most comparative tests use volvocine algae, which feature study both the evolution of multicellularity (e.g., Kirk 2005; internal fertilization. We broaden this theory by comparing broadcast- Herron and Michod 2008) and transitions from isogamy to spawning predictions with two plausible internal-fertilization scenarios: gamete casting/brooding (one mating type retains gametes internally, anisogamy and oogamy (e.g., Knowlton 1974; Bell 1982; No- the other broadcasts them) and packet casting/brooding (one type re- zaki 1996; da Silva 2018; da Silva and Drysdale 2018; Han- tains gametes internally, the other broadcasts packets containing gametes, schen et al.
    [Show full text]
  • Plant Reproduction Main Idea Reproduction in Plants Can Be Asexual Or Sexual
    Plant Plants have adaptations that enable them to reproduce in specific habitats. Reproduction Section 1 Introduction to Plant Reproduction Main Idea Reproduction in plants can be asexual or sexual. Plant life cycles include an alternation of generations. Section 2 Seedless Reproduction Main Idea The joining of a seedless plant’s egg and sperm requires moist condi- tions and produces a spore. Section 3 Seed Reproduction Main Idea Reproduction in seed plants involves pollen grains—the sources of sperm, and ovules—the sources of the eggs. The joining of eggs and sperms can produce seeds. A Forest from Ashes Saplings and other plants are growing among the remains of trees destroyed by fire. Where did these new plants come from? Some may have grown from seeds, and others may have grown from roots or stems that survived underground. These plants are the result of plant reproduction. Science Journal List three plants that reproduce by forming seeds. 270 Massimo Mastrorillo/CORBIS Start-Up Activities Plant Reproduction Make the following Foldable to compare and contrast the sexual and Do all fruits contain seeds? asexual characteristics of a plant. You might know that most plants grow from seeds. Seeds are usually found in the fruits of STEP 1 Fold one sheet of paper lengthwise. plants. When you eat watermelon, it can contain many small seeds. Do some plants produce fruits without seeds? Do this lab to find out. STEP 2 Fold into thirds. 1. Obtain two grapes from your teacher. Each grape should be from a different plant. 2. Split each grape in half and examine the STEP 3 Unfold and draw overlapping ovals.
    [Show full text]
  • Plants and Fungi Evolved Together As Life Moved Onto Land Over 400 Million Years Ago
    4/30/2014 The lives of modern plants and fungi are intertwined •We depend on plants and indirectly, fungi for much of our and the Colonization of Land food. •Plants are often harmed by fungi. •On the other hand, nearly all plants in the wild are aided by mycorrhizal fungi. Mycorrhizae are rootlike structures made of both fungi and plants. The fungi help plants obtain nutrients and water, and protect plant roots from parasites, in exchange for food the plants make by photosynthesis. •Modern agricultural practices , such as killing parasitic fungi with fungicides, may disrupt micorrhizal fungi, forcing the need for fertilizer. Plants and fungi evolved together as life moved onto land over 400 million years ago. This is supported by the earliest plant fossils having micorrhizae. What is a plant? •Life on land imposes problems. Water and nutrients are concentrated in the ground, while carbon dioxide and light •In the two-kingdom system, Linnaeus classified algae as are most abundant above the ground. Air provides no plants. In the five-kingdom system, algae are protists. support against the forces of gravity and will dry out reproductive cells. •The definition of plants as multicellular, eukaryotic photosynthesizers also describes multicellular algae. •Adaptations to terrestrial environment in plants include the following (a) Discrete organs: roots, stems, leaves, and •Multicellular seaweeds, the most complex algae, are gametangia specialized for anchorage and absorption, support, adapted for life in water, while plants are adapted for life on photosynthesis and reproduction, respectively. (b) Mycorrhizal land. All the resources, including water, carbon dioxide, fungi to increase the efficiency of absorption of their roots.
    [Show full text]
  • GENERAL BOTANY Lecture 32 - Bryophytes
    Jim Bidlack - BIO 1304 GENERAL BOTANY Lecture 32 - Bryophytes COMMENT: WELCOME TO THE WORLD OF PLANTS!! (WE'RE NOW IN KINGDOM PLANTAE) I. General characteristics of the Bryophyte Phyla A. Similarities to algae 1. Produce free-swimmin' sperm that travel through water to reach the eggs 2. No vascular system 3. No lignified tissue 4. Lack roots and true leaves B. What makes Bryophytes members of the Kingdom Plantae? 1. Eucaryotic 2. Lack chitinous walls (cellulose instead) & photosynthesis 3. Embryos have a jacket of sterile cells encasing reproductive cells C. Special characteristics of Bryophytes 1. Eggs formed in archegonia; sperm produced in antheridia 2. Chief photosynthetic body is the gametophyte (haploid) - note that Bryophytes demonstrate the sporic life cycle (sporophyte & gametophyte) 3. Structure is usually thallus 4. Uses: ecological importance, aesthetic value, absorbing ability, food, and medicine 5. May be the evolutionary link between algae and higher plants II. Characteristics of Bryophyte Phyla A. Phylum Hepaticophyta (liverworts - "HHHHEEEEPPPPPTTTTT!!!! [liver]") - small, green, ribbon-shaped plants 1. Two generations: gametophyte (predominant) and sporophyte 2. Ribbon-shaped thallus can often form a rosette 3. Female part (archegonia) has a head that looks like a palm tree (archegoniophore); male part (antheridia) has a head that looks like an umbrella (antheridiophore) 4. Collective term for archegonia and antheridia is gametangia B. Phylum Antherocerotophyta (hornworts - "antlers [horns]"): looks like liverwort except that the sporophyte has a much longer structure 1. Two generations: gametophyte is a ribbon-shaped thallus and sporophyte towers over the gametophyte 2. Hornworts are unique because they only have one large chloroplast per cell and those chloroplasts have pyrenoids (mosses and liverworts have many chloroplasts and lack pyrenoids) C.
    [Show full text]