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Taksonomi Tumbuhan KRT-2010 1 Introduction Taxonomy is the science of classifying and identifying plants. Scientific names are necessary because the same common name is used for different plants in different areas of the world. Latin is the language used for scientific classification. KRT-2010 2 Karl von Linne (1707-1778) Swedish botanist Developed binomial classification scheme for plants. Uses two Latin words to indicate the genus and the species. Changed his name to the Latin name of Carolus Linnaeus. KRT-2010 3 Scientific Names The first word is the genus and the second word is the species. If there are additional words, they indicate the variety or cultivar. KRT-2010 4 Scientific Classification Kingdom Phylum/Division Class Order Suborder Family Genus Species KRT-2010 5 Names and Terms Division: The major category is called a division and is equivalent to Phylum in the animal kingdom Division names endings indicate plants (phyta) and fungi (-mycota) Class Monocotyledoneae & Dicotyledoneae Order (-ales) Family (-aceae) Genus & Species KRT-2010 6 Family Biologists classify living organisms by their relatedness. The basic categories are: Kingdom Division (Phylum for animals) Class Order Family Increasing degree Genus of specificity – towards a single, Species definable, named species. KRT-2010 7 An example of phylogentic classification (Joran Viers-Basic Botany) Kingdom=Plantae; Organisms that usually have rigid cell walls and usually possess chlorophyll. Subkingdom=Embryophyta; Plants forming embryos. Phylum=Tracheophyta; Vascular plants. Subphylum=Pterophytina; Generally large, conspicuous leaves, complex vascular system. Class=Angiospermae; Flowering plants, seed enclosed in ovary. Subclass=Dicotyledoneae; Embryo with two seed leaves. Order=Sapindales; Soapberry order consisting of a number of trees and shrubs. Family=Aceraceae; Maple family. Genus=Acer; Maples and box elder. Species=Acer rubrum; Red maple. KRT-2010 8 Divisions The four most important divisions of the plant kingdom are…. – Thallophyta Algae dan Fungi – Bryophyta – Pteridophyta – Spermatophyta KRT-2010 9 Spermatophyta Includes flowering or seed-bearing plants. The two subdivisions are…. – Gymnosperms – Angiosperms KRT-2010 10 salah satu cabang ilmu botani yang mempelajari pengelompokan tumbuhan. Kata Taksonomi berasal dari Bahasa Yunani yaitu taxis yang berarti susunan dan penataan dan nomos yang berarti hukum atau aturan. KRT-2010 11 Lawrence (1969) mendefinisikannya sebagai studi yang meliputi identifikasi, tatanama (nomenclature) dan klasifikasi dari suatu obyek Ilmu taksonomi modern : mencakup studi tentang hubungan kekerabatan antar spesies (filogenetik) maupun proses-proses evolusi yang terkait (misalnya hibridisasi, variasi dalam populasi dan asal muasal suatu jenis). KRT-2010 12 Ada 4 komponen dasar dalam Taksonomi : 1. Klasifikasi: penyusunan kelompok-kelompok tumbuhan ke dalam suatu tingkatan taksonomi berdasarkan sifat-sifat tertentu. 2. Identifikasi, yaitu determinasi suatu nama untuk suatu spesies. 3. Deskripsi, adalah penjabaran karakter-karakter atau ciriciri suatu spesies. Biasanya digunakan untuk membedakan antara suatu spesies dengan spesies lainnya 4. Tatanama (Nomenclature), suatu sistem aturan yang jelas dan bersifat universal yang digunakan oleh semua ahli botani di dunia untuk menamakan tumbuhan yang tertuang dalam Kode Internasional untuk Tatanama Tumbuhan (International Code of Botanical Nomenclature, ICBN). KRT-2010 13 Sistem klasifikasi dalam taksonomi tumbuhan: sistem klasifikasi alam atau sistem klasifikasi filogenetik dan sistem klasifikasi buatan (berdasarkan habitat) Sistem klasifikasi yang tinjauannya didasarkan modifikasi dari sistem yang telah ada dengan penambahan data yang baru, disebut sistem kontemporer. *Identifikasi tumbuhan adalah menentukan namanya yang benar dan tempatnya yang tepat dalam sistem klasifikasi KRT-2010 14 Classification - 5 kingdoms (Whittaker, 1969) Prokaryotae or Monera Protista Fungi Plantae Animaliae Classification - 3 kingdoms or domains (Woese, 1978) Eubacteria - true bacteria Archaebacteria - ancient bacteria Eukaryotes - protists, fungi, plants, animals Viruses???? KRT-2010 15 KRT-2010 16 KRT-2010 17 Prokaryotes come in a variety of shapes Cocci – spherical come in clusters (staphylococci) or chains ( streptococci) Bacilli – rod shaped Curved or spiral shaped (syphillus, a spirochete is an example) KRT-2010 18 KRT-2010 19 Archaea thrive in extreme environments Can survive in very salty places. Salt water 3%, thrive at 15-20% Live in water above 100 degrees C Live in acid pools Live in anaerobic environments KRT-2010 20 Structural adaptations KRT-2010 Bacteria and archaea have flagella to move about Pili help stick to surfaces Bacteria can form an endospore to survive harsh conditions (anthrax and botulism) Filaments on actinomycetes allow organism to bridge dry gaps between soil particles 21 Bacteria Bacteria have been on the Earth for millions of years. It wasn't until the late 1600s that scientists discovered bacteria. In fact, bacteria were discovered by accident. KRT-2010 22 Anton van Leeuwenhoek accidentally noticed them while looking at scrapings from his teeth through a very simple microscope. He did not know what they were, but he was essentially the first person to see bacteria. KRT-2010 23 Bacteria are very small – smaller than most animal cells They can be rod shaped, spherical or spiral KRT-2010 24 These bacteria are all around us in the environment KRT-2010 25 Bergey’s Manual of Systematic Bacteriology - 2nd ed Vol. 1 Archae & Deeply Branching & Phototrophic Bacteria Vol. 2 Proteobacteria Vol. 3 The Low G+C Gram-positive Bacteria Vol. 4 The High G+C Gram-positive Bacteria Vol. 5 The Planctomycetes, Spirochaetes, Fibrobacteria Bacteroidetes & Fusobacteria KRT-2010 26 Archae - archaebacteria Diverse morphologically rods, cocci, spirilli, pleomorphic Gram- positive or Gram-negative Diverse metabolically aerobes, facultative anaerobes, strict anaerobes inorganic to organic electron sources psychrophiles, mesophiles, thermophiles ether-linked lipids some produce methane most thermophiles Cell wall Molecular - some characteristics like bacteria some characteristics like eukaryotes KRT-2010 27 Prokaryotic cell Shapes: rod (bacillus, bacilli) sphere (coccus, cocci) spiral (spirillum, spirilli) pleomorphic Cell arrangement: single cell pairs (diplococcus) chains clusters KRT-2010 28 Prokaryotic cell structure Capsule - external carbohydrate (protection, adhesion) KRT-2010 29 Prokaryotic cell structure Capsule Flagellum -(motility; antigenic) KRT-2010 30 Prokaryotic cell structure Capsule Flagellum Fimbria (fimbriae) &: Pilus (pili) - tubules (attachment; DNA transfer) Cell wall - mucopeptide (rigidity; protection) Gram-positive & Gram-negative Lipopolysaccharide (LPS) Cell membrane - (permeability, transport) osmosis & osmotic pressure Cytoplasm KRT-2010 31 Prokaryotic cell structure Capsule Flagellum Fimbria (fimbriae) & Pilus (pili) Cell wall Cell membrane Cytoplasm Endospore - hardy, resistant structure (survival) KRT-2010 32 Prokaryotic Cells Simplest organisms – Cytoplasm is surrounded by plasma membrane and encased in a rigid cell wall composed of peptidoglycan. no distinct interior compartments –gram-positive – thick single layer wall that retains a violet dye from Gram stain procedure –gram-negative – multilayered wall does not retain dye Susceptibility of bacteria to antibiotics depends on cell wall structure. KRT-2010 33 SPIROCHETES helical rods with axial filament motile habitat: mud to intestinal tract metabolism: chemoheterotrophs aerobic to anaerobic saprophytes to obligate parasites Treponema pallidum - syphillis T. partenue - yaws Borellia burgdorferi - Lyme disease Leptospira - leptospirosis KRT-2010 34 HELICAL or VIBROID Gram-negative Bacteria helical to comma shaped rods Campylobacter fetus - spontaneous abortion C. jejuni - food-borne intestinal disease Helicobacter pylori - ulcers KRT-2010 35 ANAEROBIC GRAM-NEGATIVE STRAIGHT, CURVED AND HELICAL RODS Bacteroides - peritonitis KRT-2010 36 GRAM-NEGATIVE AEROBIC RODS AND COCCI Pseudomonadaceae Azotobacteriaceae Rhizobiaceae Legionellaceae Neisseriaceae Unknown affiliation: Brucella, Bordatella, Francisella KRT-2010 37 FACULTATIVELY ANAEROBIC GRAM-NEGATIVE RODS Enterobacteriaceae Escherichia Serratia Salmonella Proteus Shigella Yersinia Klebsiella Vibrionaceae Vibrio Pasteurellaceae Pasteurella Hemophilus Uncertain affiliation Gardnerella KRT-2010 38 RICKETTSIALES AND CHLAMYDIALES Gram-negative Obligate intracellular parasites Rickettsia insect vector Chlamydia sexually transmitted MYCOPLASMA no rigid wall - soft skin triple layered membrane pleomorphic Mycoplasma KRT-2010 39 GRAM-POSITIVE COCCI Micrococcaceae Aerobic to facultatively anaerobic Single cell to irregular clusters Staphylococcus Streptococcaceae Anaerobic Pairs to chains “Lactic acid bacteria” Streptococcus KRT-2010 40 ENDOSPORE -FORMING GRAM-POSITIVE RODS & COCCI Large rod shaped cells Grow in chains Produce hardy, resistant endospore Bacillus - aerobic Clostridium - anaerobic KRT-2010 41 REGULAR NON-SPORING GRAM-POSITIVE RODS Lactobacillus Listeria IRREGULAR NON-SPORING GRAM-POSITIVE RODS cells pleomorphic: club-shaped, spindle-shaped, dumbells Corynebacterium Actinomyces KRT-2010 42 MYCOBACTERIA Rod-shaped cells Aerobic Non-motile Waxy coat; don’t stain readily Acid-fast Mycobacterium M. tuberculosis M. leprae KRT-2010 43 Some bacteria cause disease KRT-2010 Exotoxins – poisons secreted by bacteria (staphylococcus aureaus can cause toxic shock syndrome, also toxic strains of e. coli) Endotoxins – poisonous glycolipid components of the cell wall of some bacteria. (salmonella – food poisoning or typhoid fever Sanitation, antibiotics and education have stopped much fatality (e.g. Lyme disease) 44 Most bacteria is not harmful In fact, many are extremely beneficial. They….. flavor cheese and make yogurt help us digest food Treat sewage Decompose dead plants and animals Help create healthy soil for growing crops KRT-2010 45 Prokaryotes help recycle chemicals and clean up the environment KRT-2010 Cyanobacteria can convert nitrogen gas to nitrogen compounds plants can use Live on the roots of legumes and contribute nitrogen to the soil Breakdown of organic wastes and dead organisms to chemicals other organisms can use Decompose organic matter in sewage sludge to material that can be used as landfill or fertilizer “oil-eating” bacteria Accumulate metals from mine waters 46 Rhizobium are symbiotic bacteria in root nodules Rhizobium fix nitrogen ( N2) into ammonium Rhizobium and plants are species specific Legumes are crops with Root nodules – Clover, peas, alfalfa KRT-2010 47 Figure 37.10x Nodules KRT-2010 48 Viruses Viruses are the tiniest of the microorganisms KRT-2010 49 Viruses cannot reproduce without taking over a host cell There is still discussion as to whether they are really living things Some are helpful to us, others cause disease KRT-2010 50 KRT-2010 51 Prokaryotic Cells Some use flagellum for locomotion – threadlike structures protruding from cell surface Bacterial cell wall Rotary motor Flagellin KRT-2010 Sheath 52 KRT-2010 53 Eukaryotic cell structure Cell membrane or Plasma membrane Cytoplasm Organelles - organized membranous components: Endoplasmic reticulum (smooth, rough) Golgi complex Lysosomes (not in plant cells) Mitochondrion (mitochondria) Plastids (chloroplast) Nucleus: Chromosomes Nucleolus KRT-2010 54 Eukaryotic Cells Characterized by compartmentalization by an endomembrane system, and the presence of membrane-bound organelles. – Central vacuole – plants, storage – Vesicles (smaller) – Chromosomes - DNA and protein – Cytoskeleton (internal protein scaffolding) – Cell walls – plants and fungi KRT-2010 55 All life on earth depends on plants. Without plants ecosystems would soon grind to a halt. Animals (and fungi) are parasitic on plants. KRT-2010 56 Basics Plants (like animals and fungi) are eukaryotes. Plants are primitively photosynthetic, relying on organelles called chloroplasts to capture light energy. (A few plants have lost this ability and are parasitic on other plants). Most have highly structured bodies, with green material growing upwards and roots growing down. Their cell walls are reinforced with tough polymers, notably cellulose and lignin. All are capable of sexual reproduction, and their classification is heavily based on studies of their reproductive organs. All exhibit a phenomenon called alternation of generations, which you may well be unaware of and which we will look at closely later in the lecture. KRT-2010 57 KRT-2010 58 Taxonomy - definitions Plants are widely taken to be the green things that make flowers Kingdom Plantae – algae, mosses, ferns, conifers, flowering plants In fact the boundaries are rather unclear, especially at the single-celled level. Modern taxonomies do no try to shoehorn unicellular eukaryotes into kingdoms alongside multicellular forms but prefer to handle them as a distinct group (with 27 phyla at the last count). Within plants, the term ‘alga’ is not a monophyletic group, with red alga very different to brown and green classes. KRT-2010 59 KRT-2010 60 Taksonomi Tumbuhan Rendah (Cryptogamae) (Tumbuhan yang berkembang biak dengan Spora) Tahun 1880 diperkenalkan suatu sistem yang membagi Cryptogamae menjadi Thallophyta, Bryophyta (berbagai jenis Lumut), Pteridophyta (Tumbuhan Paku). Ciri : - Sel telah berinti, tetapi belum berdeferensiasi (belum punya berkas pengangkut) - Sporangia dan gametangianya belum diselubungi oleh dinding sel. Thallophyta (Tumbuhan Thallus): terdiri dari dua anak kelas Algae dan Fungi dibedakan dari Bryophyta dan Pteridophyta berdasarkan pada struktur alat penghasil spora dan gamet serta perkembangan zigotnya. KRT-2010 61 Algae An Overview KRT-2010 62 Algae Algae are a type of protist that usually live in water and can produce their own food. KRT-2010 63 Some algae can be large, others are microscopic KRT-2010 64 Characteristics Range in size from microscopic to single celled organisms to large seaweed Autotrophic Form the reproductive structures – gametangia or gamete chambers Aquatic and have flagella at some point in life Often contain pyrenoids, organelles that synthesis and store starch KRT-2010 65 STRUCTURE Thallus (haploid) Four types of algae –Unicellular –Colonial –Filamentous –multicellular KRT-2010 66 IDENTIFY THE TYPE OF ALGAE KRT-2010 67 CLASSIFICATION OF ALGAE SEVEN PHYLUM/DIVISION BASED ON: – – – – 1. 2. 3. 4. 5. 6. 7. COLOR TYPE OF CHLOROPHYLL FOOD-STORAGE SUBSTANCE CELL WALL COMPOSITION PHYLUM/DIVISION: CYANOPHYTA MONERA CHRYSOPHYTA PROTISTA Unicellular Eukaryote PYRROPHYTA PROTISTA Unicellular Eukaryote EUGLENOPHYTA CHLOROPHYTA PHAEOPHYTA RHODOPHYTA KRT-2010 68 Algae can be Red Brown Yellow Or Green KRT-2010 69 Algae are important to the ocean’s ecosystem They provide food for Fish Whales sea animals KRT-2010 70 Protozoans Protazoans are microsopic organisms that usually live in water KRT-2010 71 Movement Protozoans move through their environment in different ways KRT-2010 72 Cilia Cilia are hair like structures that wave back an forth moving the protozoan back and forth KRT-2010 73 A 3-d Image of cilia KRT-2010 74 Flagela A tail like structure that propels and can capture prey KRT-2010 75 Psudopods Little “ feet” that move and pull the creature as it moves KRT-2010 76 Microorganisms Require food, air and a way to dispose of waste Are found everywhere KRT-2010 77 REPRODUCTION MOST REPRODUCE BOTH SEXUALLY AND ASEXUALLY – Most sexual reproduction is triggered by environmental stress – Asexual Reproduction Mitosis – Sexual Reproduction Meiosis Zoospores Plus and minus gametes Zygospore KRT-2010 78 Reproduction in Multicellular Algae Oedogonium reproduction – Antheridium-release flagellated sperm that swim to the oogonium – Oogonium-houses the zygote which is a diploid spore oogonium The spore undergoes meiosis and produces 4 haploid zoospores. One of the four cells becomes a rootlike holdfast the others divide and become a new filament. KRT-2010 79 holdfast KRT-2010 80 Spirogyra reproduce sexually by conjugation KRT-2010 81 Ulva Reproduces by Alternation of Generations Two distinct multicellular phases- one is haploid and the other is diploid – Gametophyte is haploid – Sporophyte is diploid KRT-2010 82 Algae mempunyai bermacam-macam bentuk tubuh: Bentuk uniseluler: bentuk uniseluler yang berflagela dan yang tidak berflagela. Bentuk multiseluler Reproduksi Vegetatif: fragmentasi, pembelahan sel, pembentukan hormogonia. Aseksual: pembentukan mitospora, zoospora, aplanospora, hipnospora, stadium pamela. Seksual: isogami, heterogami yang terdiri dari anisogami dan oogami, aplanogami, autogami. KRT-2010 83 Protists – Unicellular eukaryotes KRT-2010 More complicated than any prokaryotes Membrane-enclosed nucleus containing multiple chromosomes Organelles characteristic of eukaryotes Eukaryotic flagella and cilia Classified into 5 kingdoms or more 84 Protozoa – Protists that ingest their food Giardia – flagellate that lives in the human intestine and can cause cramps and diarrhea Trypanosoma – live in the blood stream of vertebrate animals cause African sleeping sickness Amoebas – large group use pseudopodia to ingest food Plasmodium – feeds on red blood cells and causes malaria KRT-2010 85 Algae – photosynthetic protists Dinoflagellate blooms can cause red tide Diatoms are unicellular and very abundant in freshwater and marine environments. Important food source for marine animals Green algae – cells resemble biflagellated gametes of many multicellular algae and some plants, have cellulose cell walls, use starch to store food and have chloroplasts KRT-2010 86 Divisio :Chrysophyta (Termasuk Protista) Ciri-ciri : - Bersifat uniselular, dinding sel terdiri atas pektin yang lunak - Selnya berinti, kromatofora mengandung klorofil a, karotin, santofil dan suatu karotenoid yang menyerupai fikosantin. - Sebagian besar bersifat autotrof, kecuali yang tidak berwarna : heterotrof. - Tempat hidup : air laut dan air tawar (sering melekat pada tumbuhan air). KRT-2010 87 Phylum Euglenophyta 1000 species of Euglenoids Have both plantlike and animal-like characteristics Fresh water KRT-2010 88 Phylum Chlorophyta Green algae 7000 diverse species Biologist reason that green algae give rise to land plants. Both green algae and land plants have chlorophyll a and B as well as carotenoids and store food as starch Both have walls made of cellulose KRT-2010 89 Divisio: Chlorophyta Ganggang Hijau Ciri-ciri 1. Pigmen, khlorofil a dan b, serta karoten. Khlorofil terdapat dalam jumlah yang banyak sehingga ganggang ini berwarna hijau 2. Hasil fotosintesis berupa amilum dan tersimpan dalam khloroplas. 3. Khloroplas berjumlah satu atau lebih; berbentuk mangkuk, bintang, lensa, bulat, pita, spiral 4. Sel mempunyai 2 atau 4 flagela sama panjang. 5. Dinding sel mengandung selulose. 6. Perkembangbiakan: aseksual dengan Zoospora dan seksual dengan anisogami Tempat hidup Sebagian besar ( ± 90%) merupakan algae air tawar terdapat pula di tanah atau di dinding tembok yang lembab, di atas batang pohon dan dapat pula sebagai epifil (pada permukaan daun). KRT-2010 90 Phylum Phaeophyta 1500 species of Brown algae Mostly marine and include seaweed and kelp All are multicellular and large (often reaching lengths of 147 feet) Individual alga may grow to a length of 100m with a holdfast, stipe and blade Used in cosmetics and most ice creams KRT-2010 91 Divisio: Phaeophyta Ganggang Coklat Ciri-ciri -Tubuh selalu berupa talus yang multiseluler yang berbentuk filamen, lembaran atau menyerupai semak/pohon yang dapat mencapai beberapa puluh meter, terutama jenis-jenis yang hidup di lautan daerah beriklim dingin. - Bersel banyak dan berwarna pirang (fikosantin) - Kromatofora mengandung klorofil a, karotin, xantofil, dan fikosantin. Tempat hidup Sebagian besar hidup di laut hanya ada beberapa jenis saja yang hidup di air tawar. KRT-2010 92 Phylum Rhodophyta 4000 species of RED Algae Most are marine Smaller than brown algae and are often found at a depth of 200 meters. Contain chlorophyll a and C as well as phycobilins which are important in absorbing light that can penetrate deep into the water Have cells coated in carageenan which is used in cosmetics, gelatin capsules and some cheeses KRT-2010 93 Divisio: Rhodophyta (Ganggang Merah) Ciri-ciri 1. Sel mempunyai dinding yang terdiri dari selulose . Rhodophyceae tidak pernah menghasilkan sel-sel berflagela. 2. Pigmen Khlorofil: terdiri dari khlorofil a, karotenoid, fikoeritrin dan fikosianin yang sering disebut pigmen aksesoris. karoten Pigmen-pigmen tersebut terdapat dalam kloroplas 3. Cadangan makanan berupa tepung floride (hasil polimerase dari glukosa) dan terdapat diluar khloroplas. 4. Talus Hampir semuanya multiseluler, hanya 2 marga saja yang uniseluler. Talus yang multiseluler berbentuk filamen silinder ataupun helaian. Talus umumnya melekat pada substrat dengan perantaraan alat pelekat. 5. Habitat : laut yang dalam KRT-2010 94 Other Phylum Representatives Diatoms – used in detergents, paint removers, toothpaste Dinoflagellates – red tides Golden algae Important in the formation of petroleum products KRT-2010 95 Seaweeds are a multicellular marine algae KRT-2010 Lack true stems, leaves, roots and internal tubes that transport nutrients and water in most plants Brown algae, red algae, and multicellular green algae may be members of 3 separate kingdoms 96 KRT-2010 97 Fungi (jamur, cendawan) Ciri-ciri: Tidak berklorofil : tidak berfotosintesis Tubuhnya mempunyai benang-benang hifa Perkembangbiakan : vegetatif : dengan spora, generatif, dengan isogami, anisogami, oogami, gametangiogami dan somatogami Hidup secara heterotrof sebagai saprofit atau parasit Jarang hidup di air, kebanyakan di daratan. KRT-2010 98 Funguslike Protist Cellular Slime molds KRT-2010 99 Cellular slime molds KRT-2010 Have both unicellular and multicellular life stages 100 Plasmodial Slime Molds KRT-2010 101 Plasmodial slime molds KRT-2010 Common everywhere there is moist and decaying matter Large and branching, but not multicellular. The weblike form increases the surface area to contact food water and oxygen When food is is scarce it addapts the reproductive structures at the bottom 102 Water Molds KRT-2010 103 THERE’S FUNGUS AMONG US Look into the eye. Look deep into the eye. There are no such things as molds. – All molds are actually fungi. KRT-2010 104 That's a bunch of fungus. That is a bit surprising. We had always heard about mold in the shower or mold on the bread. KRT-2010 105 . Mold is actually a type of fungus. It has a shape called a zygote to be exact. While yeasts are single celled fungi, molds are multicellular fungi Bread takes one kind of fungus (yeast) to make it rise. If you leave the bread out, another type of fungus comes in (bread mold) to break it down. It's not amazing, but it's true. KRT-2010 106 Let's look at Club Fungi Mushrooms! KRT-2010 107 So what is a mushroom exactly? It is bunches of strands living underground called hyphae (pronounced hi-fah). Those strands are the basic fungus in action, decomposing leaves, or rotting bark on the ground. KRT-2010 108 When it's time to reproduce, they develop a stalk and cap,the mushroom that you see popping out of the ground. KRT-2010 109 It's only one part of the fungus. On the bottom of that cap are a set of gills that have little clubs with fungus spores. KRT-2010 110 ZYGOTES We already talked a little about mold. That is only one example of the Zygote Fungi. These have hyphae-like mushrooms but they reproduce in a different way. When it's time to make more fungi, they create a stalk and release something called zygospores (thus the name zygote). KRT-2010 111 When your bread gets old and green or black, you are seeing a type of zygote fungus in action. If you wait long enough, you will see the stalks develop and the zygotes released. KRT-2010 112 SINGLE CELLS Now lets look at Sac Fungi, simple, single celled fungi. KRT-2010 113 Fungi KRT-2010 Heterotrophic – they cannot make their own food molecules Some like mycorrhizae absorb essential minerals from the soil needed by plants About 80% of plant disease is caused by fungi which are parasites Many decompose organic matter 114 Fungi absorb food after digesting it outside their bodies Secrete powerful enzymes that digest their food externally then absorb the nutrient molecules Multicellular except yeast Mycelium is a feeding network of hyphae Mushroom is just the above ground reproductive structure of a much more extensive underground mycelium Not celllulose cell walls, but chitin which is a polymer of a nitrogencontaining sugar No flagellated cells in their life cycle KRT-2010 115 KRT-2010 116 Lichens – fungi living mutualistically with photosynthetic organisms KRT-2010 The mutualistic merger is so complete they are actually named as a species Gives the two organisms the ability to survive in habitats that are inhospitable to either alone Can tolerate severe cold, withstand severe drought but sensitive to air pollutants 117 Mycorrhizae are symbiotic / mutual fungi on roots Mycorrhizae: a) increase surface area of roots b) produce antibiotics to ward off competing plants c) Are specie specific to plants d) Helped plants evolve on land e) Seeds exposed to fungi spores grow better The plant provides carbohydrates to the fungus KRT-2010 118 , I am not mold ! I am not rotting you! I am Mycorrhizae, I am a fun guy KRT-2010 119 Fungi have enormous ecological impact KRT-2010 Decomposers and recyclers of organic matter Used to ripen cheese Yeasts used in baking, brewing and winemaking Produce antibiotics As well as the mutualistic partners in mycorrhizae and lichens 120 YEAST Yeast is used to make several types of food for humans. We need yeast to make breads. We also use them to make alcohol. It's a whole process called fermentation. KRT-2010 121 Some fungi are beneficial. Sugars are broken down in an environment without oxygen. It's called anaerobic fermentation. And voila, alcohol. Even though they are single celled, you may find them in colonies. They reproduce very quickly and hang out together. It takes a lot of them (because they are so small) to get a lot of work done KRT-2010 122 Parasitic fungi KRT-2010 Corn smut, Dutch elm disease and botrytis Some of the fungi that attach food crops are toxic to humans LSD is from the toxin in ergots in grain crops Mycosis – fungal infection (ringworm, athlete’s foot, vaginal yeast infections) 123 Plant diversity is a nonrenewable resource KRT-2010 124 Antibiotics one of the first antibiotics was called penicillin. It was developed from a fungus (a fungus named Penicillium found on an orange, to be exact). KRT-2010 125 Classification of the plants we will cover in this course. Bryophytes (mosses, liverworts) Pteridophytes Ferns and allies Gymnosperms: Conifers, cycads etc Angiosperms: Flowering plants Mesozoic 120MYBP Carboniferous 350MYBP Devonian 400MYBP Seeds Vascular tissues (tracheids or derivatives) KRT-2010 126 Nonvascular Plants Bryophytes Fewer than 19,000 species Three groups Liverworts Hornworts Mosses KRT-2010 127 Bryophytes KRT-2010 Includes mosses Have a cuticle and embryos retained on the parent plant Lack vascular tissue, but some have waterconducting tubes Lack internal support Plants grow in a tight pack holding each other up Flagellated sperm must swim 128 Bryophytes Small, nonvascular, nonwooody Gametophyte dominates life cycle; has leaflike, stemlike, and rootlike parts Usually live in wet habitats Flagellated sperm require water to reach eggs KRT-2010 129 Bryophytes These are the mosses and liverworts, both relatively common wellknown groups of non-flowering plants typical of permanently damp areas. (Actually a few specialise in dry open sites – fire sites, bare concrete etc). The dominant phase is a leafy form (the gametophyte), which is genetically different to the stalked pods that produce its spores. A typical moss, showing the spore capsule, which is a genetically different plant to the green fronds from which it grows. (More later..) KRT-2010 130 Types of Bryophytes Mosses (most common) Liverworts (simplest) Hornworts KRT-2010 131 The hepatica: Liverworts. These also make genetically distinct spore-dispersing individuals, but here the spores are dispersed from an umbrella-like structure, while the main plant (the gametophyte) is generally flattened, plate-like. sporophytes c. 2 cm The common liverwort Marchantia KRT-2010 132 Marchantia: A Liverwort Reproduces Do not post on Internet asexually by gemmae Gametophytes are male or female Female gametophyte KRT-2010 Figure 23.7 133 Page 389 Moss Life Cycle zygote Zygote grows, develops into a sporophyte while still attached to gametophyte. mature sporophyte Diploid Stage Fertilization Haploid Stage Meiosis Spores germinate. spermproducing structure Figure 23.5 Page 388 eggproducing structure KRT-2010 male gametophyte female gametophyte 134 Peat Mosses 350 species Sphagnum is an example Grow in acidic bogs; important ecosystems of cold and temperate regions Peat can be harvested and burned as fuel KRT-2010 135 Tumbuhan lumut (Bryophyta) merupakan sekumpulan tumbuhan kecil yang termasuk dalam divisio Bryophyta (dari bahasa Yunani bryum, "lumut"). Tumbuhan ini tingkatannya lebih tinggi dari Thallophyta dengan habitus yang ber-macam2. - Warna hijau 9klorofil a dan b) - Selnya berdinding terdiri dari selulosa - Alat kelamin terdiri atas anteridium dan arkegonium - Terdiri dari lumut daun (musci) dan lumut hati (hepaticae) organ penyerap haranya adalah rizoid (: "serupa akar"). Daun tumbuhan lumut dapat berfotosintesis. Tumbuhan lumut merupakan tumbuhan pelopor, yang tumbuh di suatu tempat sebelum tumbuhan lain mampu tumbuh. KRT-2010 136 Perkembangbiakan Tumbuhan lumut mengalami pergiliran keturunan dalam daur hidupnya. Apa yang dikenal orang sebagai tumbuhan lumut merupakan tahap gametofit (tumbuhan penghasil gamet) yang haploid (x = n). Dengan demikian, terdapat tumbuhan lumut jantan dan betina karena satu tumbuhan tidak dapat menghasilkan dua sel kelamin sekaligus. Sel-sel kelamin jantan (sel sperma) dihasilkan dari anteridium dan sel-sel kelamin betina (sel telur atau ovum) terletak di dalam arkegonium. Kedua organ penghasil sel kelamin ini terletak di bagian puncak dari tumbuhan. Anteridium yang masak akan melepas sel-sel sperma. Sel-sel sperma berenang (pembuahan terjadi apabila kondisi lingkungan basah) menuju arkegonium untuk membuahi ovum. Ovum yang terbuahi akan tumbuh menjadi sporofit yang tidak mandiri karena hidupnya disokong oleh gametofit. Sporofit ini diploid (x = 2n) dan berusia pendek (3-6 bulan untuk mencapai tahap kemasakan). Sporofit akan membentuk kapsula yang disebut sporogonium pada bagian ujung. Sporogonium berisi spora haploid yang dibentuk melalui meiosis. Sporogonium masak akan melepaskan spora. Spora tumbuh menjadi suatu berkas-berkas yang disebut protonema. Berkas-berkas ini tumbuh meluas dan pada tahap tertentu akan menumbuhkan gametofit baru. KRT-2010 137 Vascular Plants Majority Have of plants internal tissues that carry water and solutes Two groups – Seedless vascular plants – Seed-bearing vascular plants KRT-2010 138 Seedless Vascular Plants Arose during the Devonian Produce spores but no seeds Four main groups Whisk ferns Lycophytes Horsetails Ferns KRT-2010 139 Seedless vascular plants KRT-2010 Includes ferns Well-developed roots and rigid stems Flagellated sperm that require water to reach eggs In many species the leaves sprout from stems that grow along the ground (fiddleheads) 140 Seedless Vascular Plants Like bryophytes – Live in wet, humid places – Require water for fertilization Unlike bryophytes – Sporophyte is free-living and has vascular tissues KRT-2010 141 Seedless Vascular Plants Lycophytes (Lycophyta) Whisk ferns (Psilophyta) Horsetails (Sphenophyta) Ferns (Pterophyta) KRT-2010 142 Pteridophytes: ferns, horsetails, club mosses and allies. Pteridophytes are the group of plants which first (as far as we can tell…) developed the tracheid cells which permit stems to rise high above any water supply, and as such were the first colonists of dry land, at least 400 MYBP. We have a good fossil record of them (in fact our industry has depended on burning this fossil record since the inception of the industrial revolution!). The facets which fossilise show that apart from the extinction of the giant forms, this group has changed little since the Devonian. Like mosses these plants have two genetically distinct phases in their life cycle, but here the dominant phase is the sporophyte, the familiar fern leaves etc. KRT-2010 143 Ferns These are ancient but still successful forms, in which the spore-bearing stage is very familiar. Bracken Pteridium aquilinum is one of the most widespread and pernicious weeds on the planet! We still have tree ferns, native to Gondwanaland (Australasia, South America, Africa) but now widely planted in tropical, subtropical and frost-free temperate areas. In all cases spores are shed from the underside of the leaves (fronds). Bracken Pteridium aquilinum A tree fern Dicksonia antarctica KRT-2010 144 Ferns (Pterophyta) 12,000 species, mostly tropical Most common sporophyte structure – Perennial underground stem (rhizome) – Roots and fronds arise from rhizome – Young fronds are coiled “fiddleheads” – Mature fronds divided into leaflets – Spores form on lower surface of some fronds KRT-2010 145 Fern Life Cycle Sporophyte still attached to gametophyte sorus zygote fertilization egg rhizome Diploid Stage meiosis Haploid Stage Spores develop Spores are released sperm Figure 23.9 Page 391 mature KRT-2010 gametophyte 146 Spore germinates Horsetails (Sphenophyta): Equisetacea These plants are every-day miracles. There are only about 15 species in the world, all in the genus Equisetum. It has changed hardly at all since the carboniferous period. I know of a Carboniferous site in Yorkshire where one can find 2m high horsetails still standing, fossilised in a cliff, looking exactly like living forms (only rather bigger, though giant horsetail E. telmateia can grow nearly this tall). Also known as Lego plants, because the stems comes apart at the nodes. KRT-2010 147 Horsetails, contd. The needle-like leaves are reinforced with silica, and have been used as pan scrubs. Few animals find them palatable. For all their ancientness and oddity they are a serious weed, with immensely deep root systems and an ability to shrug off herbicides. Gardeners’ Question Time (BBC) advice on how to respond to horsetails in your garden Sell your house, in winter when the stems aren’t visible. KRT-2010 148 Club mosses (Lycophyta): Lycopodiacea These rather nondescript crawling plants are nowadays confined to a minor role in northern forests on acid soils. Present in the UK but easily overlooked. The sole survivors of a large group including vast forestforming trees in the carboniferous, the first terrestrial forests. The have a vascular system, and always one vein running along the leaf axis. KRT-2010 149 Pteridophyta / Filicophyta (Tumbuhan paku / paku-pakuan ) Daur hidup (metagenesis) : - Daur hidup tumbuhan paku : pergiliran keturunan, yang terdiri dari dua fase utama:gametofit dan sporofit. Tumbuhan paku yang mudah kita lihat merupakan bentuk fase sporofit karena menghasilkan spora. Bentuk generasi fase gametofit dinamakan protalus (prothallus) atau protalium (prothallium), yang berwujud tumbuhan kecil berupa lembaran berwarna hijau, mirip lumut hati, tidak berakar (tetapi memiliki rizoid sebagai penggantinya), tidak berbatang, tidak berdaun. - Prothallium tumbuh dari spora yang jatuh di tempat yang lembab. Dari prothallium berkembang anteridium (antheridium, organ penghasil spermatozoid atau sel kelamin jantan) dan arkegonium (archegonium, organ penghasil ovum atau sel telur). Pembuahan mutlak memerlukan bantuan air sebagai media spermatozoid berpindah menuju archegonium. - Ovum yang terbuahi berkembang menjadi zigot, yang tumbuh menjadi tumbuhan paku Setelah terjadi pembuahan (zigot berkembang), protalium hilang KRT-2010 150 Morfologi - Akar yang tumbuh pertama tidak dominan, disusul akar lain yang tumbuh dari batang - Batang bercabang, menggarpu - Dapat berbentuk semak , pohon sampai beberapa meter. - Ukuran daun bervariasi sampai 6 m;pada umumnya berdaun majemuk;” tipe daun kecil, tidak bertangkai dan hanya mempunyai satu tulang daun, tersusun rapat menurut garis spiral (Lycopsida=paku kawat)”. Perkembangbiakan : vegetatif : spora - Sporangium dan spora terdapat pada daun-daun khusus : sporofil (sering terkumpul membentuk alat yang menyerupai bunga pada Spermatophyta). KRT-2010 151 Berdasarkan klasifikasi baru (Smith et al., 2006), tumbuhan paku dapat dikelompokkan sebagai berikut: Divisio: Lycophyta dengan satu kelas: Lycopsida. Divisio: Pteridophyta dengan empat kelas : Psilotopsida, mencakup Ophioglossales. Equisetopsida Marattiopsida Polypodiopsida (=Pteridopsida, Filicopsida) KRT-2010 152 Kelas Psilotopsida Bangsa Ophioglossales Suku Ophioglossaceae (termasuk Botrychiaceae, Helminthostachyaceae) Bangsa Psilotales Suku Psilotaceae (termasuk Tmesipteridaceae) Kelas Equisetopsida [=Sphenopsida] Bangsa Equisetales Suku Equisetaceae Kelas Marattiopsida Bangsa Marattiales Suku Marattiaceae (termasuk Angiopteridaceae, Christenseniaceae, Danaeaceae, Kaulfussiaceae) Kelas Polypodiopsida [=Filicopsida, Pteridopsida] Bangsa Osmundales Suku Osmundaceae Bangsa Hymenophyllales Suku Hymenophyllaceae (termasuk Trichomanaceae) Bangsa Gleicheniales Suku Gleicheniaceae (termasuk Dicranopteridaceae, Stromatopteridaceae) Suku Dipteridaceae (termasuk Cheiropleuriaceae) Suku Matoniaceae 153 KRT-2010 Bangsa Schizaeales Suku Lygodiaceae Suku Anemiaceae (termasuk Mohriaceae) Suku Schizaeaceae Bangsa Salviniales Suku Marsileaceae (termasuk Pilulariaceae) Suku Salviniaceae (termasuk Azollaceae) Bangsa Cyatheales Suku Thyrsopteridaceae Suku Loxomataceae Suku Culcitaceae Suku Plagiogyriaceae Suku Cibotiaceae Suku Cyatheaceae (termasuk Alsophilaceae, Hymenophyllopsidaceae) Suku Dicksoniaceae (termasuk Lophosoriaceae) Suku Metaxyaceae Bangsa Polypodiales Suku Lindsaeaceae (termasuk Cystodiaceae, Lonchitidaceae) Suku Saccolomataceae Suku Dennstaedtiaceae (termasuk Hypolepidaceae, Monachosoraceae, Pteridiaceae) KRT-2010 154 Suku Pteridaceae (termasuk Acrostichaceae, Actiniopteridaceae, Adiantaceae, Anopteraceae, Antrophyaceae, Ceratopteridaceae, Cheilanthaceae, Cryptogrammaceae, Hemionitidaceae, Negripteridaceae, Parkeriaceae, Platyzomataceae, Sinopteridaceae, Taenitidaceae, Vittariaceae) Suku Aspleniaceae Suku Thelypteridaceae Suku Woodsiaceae (termasuk Athyriaceae, Cystopteridaceae) Suku Blechnaceae (termasuk Stenochlaenaceae) Suku Onocleaceae Suku Dryopteridaceae (termasuk Aspidiaceae, Bolbitidaceae, Elaphoglossaceae, Hypodematiaceae, Peranemataceae) Suku Lomariopsidaceae (termasuk Nephrolepidaceae KRT-2010 155 Suku Tectariaceae Suku Oleandraceae Suku Davalliaceae Suku Polypodiaceae (termasuk Drynariaceae, Grammitidaceae, Gymnogrammitidaceae, Loxogrammaceae, Platyceriaceae, Pleurisoriopsidaceae) KRT-2010 156 Seed-Bearing Vascular Plants Gymnosperms first arose – Cycads – Ginkgos – Gnetophytes – Conifers Angiosperms arose later – Monocots – Dicots KRT-2010 157 Evolutionary Trend Figure 23.2 Page 386 zygote GREEN ALGA BRYOPHYTE KRT-2010 FERN GYMNOSPERM ANGIOSPERM 158 Traits of Seed-Bearing Plants Pollen grains – Arise from megaspores – Develop into male gametophytes – Can be transported without water Seeds – Embryo sporophyte inside nutritive tissues and a protective coat – Can withstand hostile conditions KRT-2010 159 Rise of Seed-Bearing Plants Seeds appeared about 360 million years ago Seed ferns and gymnosperms were dominant at first Angiosperms arose later KRT-2010 160 Carboniferous Giant Sea lycophytes and horsetails level rose and fell repeatedly Remains of swamp forests were repeatedly submerged and compressed Formation of coal KRT-2010 161 Seed-Bearing Plants Microspores that give rise to pollen grains Megaspores More inside ovules water-conserving than seedless vascular plants KRT-2010 162 SPERMATOPHYTA -Tingkat perkembangan yang paling tinggi -Telah menghasilkan biji: tumbuhan berbiji (Spermatophyta) -Biji berasal dari bunga : Tumbuhan Berbunga (Anthophyta) -Dibagi menjadi 2 sub divisi: tumbuhan berbiji telanjang (Gymnospermae) dan berbiji tertutup = bakal biji terbungkus oleh karpela/daun buah (Angiospermae) - Angiospermae terdiri dari dua kelas : Dicotyledoneae (tumbuhan biji belah/memiliki dua daun lembaga) dan Monocotyledoneae ( mempunyai satu daun lembaga) KRT-2010 163 - Kesepakatan umum tentang bagaimana tumbuhan berbunga dikelompokkan mulai tercapai sejak hasil "Angiosperm Phylogeny Group" (APG) dikeluarkan pada tahun 1998 dan diperbaharui (update) pada tahun 2003 sebagai Sistem Klasifikasi APG II. - Jenisnya diperkirakan berkisar antara 250 000 hingga 400 000 yang dikelompokkan menjadi 462 suku/famili (APG, 1998). - Dari keseluruhan spesies: monokotil = 23% dikotil= 75%. KRT-2010 164 Sepuluh besar suku tumbuhan menurut banyaknya jenis adalah sebagai berikut: Asteraceae atau Compositae (suku kenikir-kenikiran): 23.600 jenis Orchidaceae (suku anggrek-anggrekan): 21.950 Fabaceae atau Leguminosae (suku polong-polongan): 19.400 Rubiaceae (suku kopi-kopian): 13.183 Poaceae, Glumiflorae, atau Gramineae (suku rumputrumputan): 10.035 Lamiaceae atau Labiatae (suku nilam-nilaman): 7.173 Euphorbiaceae (suku kastuba-kastubaan): 5.735 Cyperaceae (suku teki-tekian): 4.350 Malvaceae (suku kapas-kapasan): 4.225 Araceae (suku talas-talasan): 4.025 Orchidaceae, Poaceae, Cyperaceae dan Araceae adalah monokotil. KRT-2010 165 Kesepuluh suku di atas mencakup beragam jenis tumbuhan penting dalam kehidupan manusia, baik dalam bidang pertanian, kehutanan maupun industri. Suku rumput-rumputan jelas merupakan suku terpenting karena menghasilkan berbagai sumber energi pangan bagi manusia dan ternak dari padi, gandum, jagung, juwawut, tebu, serta sorgum. Suku polong-polongan menempati tempat terpenting kedua, sebagai sumber protein nabati dan sayuran utama dan berbagai peran budaya lain (kayu, pewarna, dan racun). Suku nilamnilaman beranggotakan banyak tumbuhan penghasil minyak atsiri dan bahan obat-obatan. KRT-2010 166 Beberapa suku penting lainnya dalam kehidupan manusia adalah: - Solanaceae (suku terong-terongan), sebagai sumber pangan penting terutama sayuran - Cucurbitaceae (suku labu-labuan), sebagai sumber sayuran penting - Brassicaceae atau Cruciferae (suku sawi-sawian), sebagai sumber sayuran dan minyak pangan penting - Alliaceae (suku bawang-bawangan), sebagai sumber sayuran bumbu penting - Piperaceae (suku sirih-sirihan), sebagai sumber rempah-rempah penting. - Arecaceae atau Palmae (suku pinang-pinangan), sebagai pendukung kehidupan penting masyarakat agraris daerah tropika - Rutaceae (suku jeruk-jerukan), Rosaceae (suku mawarmawaran), dan Myrtaceae (suku jambu-jambuan) banyak menghasilkan buah-buahan penting. KRT-2010 167 Tumbuhan berbunga juga menjadi pemasok sumberdaya alam dalam bentuk kayu, kertas, serat (misalnya kapas, kapuk, and henep, serat manila), obat-obatan (digitalis, kamfer), tumbuhan hias (ruangan maupun terbuka), dan berbagai daftar panjang kegunaan lain. KRT-2010 168 Gymnosperms Naked seed because it isn’t produced in a specialized chamber Conifers – pine, spruce, and fir are the largest group KRT-2010 169 Gymnosperms This group contains many well-known plants, including all coniferous trees (pines, larch, spruce etc), yews and allies, along with other ‘living fossils’ the cycads, plus a few simple plain oddities thrown in to keep botanists happy. Gymnosperm means ‘naked seed’, and indeed in this group the fertilised seed protrudes from the cone/aril. They have apparently lost the sporophyte generation (but see later), and are now trees which shed viable seed that germinates to make a new tree – the pattern of seed germination which we are familiar with. They have tracheids allowing water to be sucked to great heights: the this group contains probably the largest (Sequoia) and oldest (Bristlecone pine, Pinus aristata) organisms in the world. KRT-2010 170 Gymnosperms Plants with “naked seeds” Seeds don’t form inside an ovary Four groups Conifers Ginkgos Cycads Gnetophytes KRT-2010 171 Conifer Characteristics Widest known, largest number of living species Woody trees or shrubs Most are evergreen Bear seeds on exposed cone scales Most produce woody cones KRT-2010 172 Conifers Female pine cone Most people know one group of gymnosperms; the conifers. Literally the cone bearers – these are pines, spruces, larches, firs etc. Cones – correctly stobili (1 strobilus) are sexual organs either shedding pollen (male cones) or bearing ovaries, awaiting fertilisation by windblown pollen (female cones). In fact all gymnosperms, plus lycoods, have similar structures. You will meet the terms microsporangia (pollenproducing organs) and megasporangia (egg producing organs). KRT-2010 male pine cone 173 Cycads Most diverse during age of dinosaurs Only 100 living species Palmlike appearance Pollen-bearing and seed-bearing cones on different plants Figure 23.14e Page 394 KRT-2010 Do not post on Internet Strobilus of a “female” cycad 174 Cycads These plants look rather like stunted palms, or possibly rather tough tree ferns, but are neither. They are gymnosperms that have changed little since the Jurassic period, when they were dominant land cover and presumably staple food for herbivorous dinosaurs. Now they are thinly scattered in tropical areas, some highly endangered. Males and females plants are separate, using a winddispersed pollen to fertilise their cones. The male gamete is notable for using cilia to swim towards the egg (the ‘highest’ occurrence of cilia in the plant kingdom). Some cycads fix atmospheric nitrogen using a symbiosis with blue-green algae living in their stems and roots. KRT-2010 175 Ginkgos Diverse during age of dinosaurs One surviving species, Ginkgo biloba Deciduous trees are male or female KRT-2010 Do not post photos on Internet Fig.176 23.15 Ginkgo biloba – the wonderful discovery People had since the early days of fossil hunting been recovering well-preserved fossil leaves from Ancient (Jurassic and earlier) which looked like an unrolled pine needle. No living plant matched this pattern. Then in 1691 the German Engelbert Kaempfer discovered strange trees with exactly this unfamiliar leaf form in Japan, cultivated in temple gardens. They proved to be living specimens of Ginkgo, one male and one female. Thankfully their seed was fertile, and has now been widely propagated. The oldest in the UK is in Oxford botanic gardens (pruned and now rather small for its age). Generally males are planted as the female flower is rather sticky and smelly. (Sex is coded by an X-Y chromosome system, as in mammals). KRT-2010 177 3 Genera of Gnetophytes Gnetum Welwitschia Ephedra Do not post on Internet Sporophyte of Ephedra KRT-2010 Figure 23.16a 178 Page 395 Welwitschia mirabilis This is certainly one of the strangest plants in the world, whose classification inside the gymnosperms has long been assumed but is confirmed by DNA analyses. It lives only in the Namib desert, South Africa, in a region where rain never falls. Instead it relies on the mist that condenses in coastal regions where cold currents from the southern oceans well up against the desert. Welwitschia has only 2 leaves, long strap-like ones that grow perpetually from their base while the ends become frayed and tatty. It is dioecious. KRT-2010 179 Pine Cones Woody scales of a “pine cone” are the parts where megaspores formed and developed into female gametophytes Male cones, where microspores and pollen are produced, are not woody KRT-2010 180 section through one ovule surface view of one cone scale (houses two ovules) Pine Life Cycle ovule surface view of one cone scale (houses a pollen-producing sac) mature sporophyte section through a pollen-producing sac seed coat zygote seeding pollen tube spermproducing cell Diploid embryo seed fertilization meiosis Haploid microspores eggs form megaspores pollination form female gametophyte KRT-2010 Figure 23.17 181 Page 396 Conifer Distribution Reproduce more slowly than angiosperms; at competitive disadvantage in many habitats Still dominate in far north, at higher elevations, and in certain parts of southern hemisphere KRT-2010 182 Angiosperms KRT-2010 Flowering plants 183 Angiosperms Flowering plants Dominant land plants (260,000 species) Ovules and (after fertilization) seeds are enclosed in an ovary Three main groups: magnoliids, monocots, and eudicots KRT-2010 184 Angiosperm Evolutionary Tree water Amborella lilies star anise magnoliids basal groups monocots eudicots Figure 23.19a KRT-2010 185 Page 398 Double Fertilization Distinctive feature of angiosperms Male gametocyte delivers two sperm to an ovule One fertilizes egg; other fertilizes a cell that gives rise to endosperm KRT-2010 186 sporophyte Flowering Plant Life Cycle Diploid Double fertilization Haploid pollination two sperm enter ovule KRT-2010 Meiosis microspores female gametophyte Meiosis mitosis without cytoplasmic division Figure 23.20 187 Page 399 Angiosperms: Monocotyledons and Dicotyledons Flowering plants (phylum Anthophyta) come in two fundamentally different ‘designs’ or classes, known as the Monocotyledons and Dicotyledons. Or Monocots and Dicots in botanical jargon. Formally these are defined by the number of seed leaves, or cotyledons, that emerge when the seed 1st germinates. In Monocotyledons it is 1, in Dicotyledons it is 2. Coinciding with this are a series of other characteristics which are so consistent that everyone seemed happy that these are monophyletic groups, splitting from the gymnosperms about 130 MYBP (early Cretaceous). KRT-2010 188 Angiosperm Classes: Monocots vs. Dicots Characteristic Monocot Dicot Flower parts Usually in threes, or multiples of threes Usually in fours or fives Cotyledons One Two Leaf venation Usually parallel Usually netlike Primary vascular bundles in stem Complex arrangement In a ring True secondary growth Absent with vascular cambium KRT-2010 Commonly present 189 Monocotyledons This truly monophyletic group contains all grasses, sedges, rushes, bamboo etc. Orchids. Pineapples and allies (the bromeliads). Lilies, and their succulent relatives Aloes. Few trees but including bananas and palms. KRT-2010 190 Dicotyledons. Actually the eudicotyledons plus a few others… It is here that I have to confess to a certain oversimplification. Neat though the division was, recent (late 1990s) DNA work has shown that the group known as ‘Dicots’ consists of 4 groups, all as unrelated to each other as they are to the monocots. Fortunately, virtually all the ones you are likely to meet are in a good monophyletic group, now called the Eudicotyledons. (Sometimes DNA research makes a good simple system needlessly complicated..) KRT-2010 191 Eudicotyledons Here we have most gardens flowers, all herbs, cacti, climbers, and most trees. KRT-2010 192 People and Plants Plant domestication began about 11,000 years ago About 3,000 species have been used as food Now about 200 plants are major crops KRT-2010 193 Nonfood Uses of Plants Lumber, paper, and fuel Furniture Rope Thatched Natural roofing insecticides Drugs KRT-2010 194 Plants of Abuse Tobacco plants are Nicotiana sp. Cannabis sativa is source of marijuana Coca leaves are used to produce cocaine Toxic plant alkaloids, such as henbane and belladona, have been used as poisons and as medicine KRT-2010 195 KRT-2010 196