Kingdom Plantae & Kingdom Fungi
Chapter 18
Plantae Characteristics Multicellular Eukaryotic Photosynthetic autotrophs Most terrestrial Cells walls made of cellulose Contain a & b chlorophyll
Evolutionary History Plants evolved from a green algae, (Chlorophyta) ~ 500 million yr ago Commonalities include Chlorophyll a & b Store excess carbs as starch Cell walls of cellulose Differences include Algae lack true roots, leaves, stems, cuticles & support tissues Some algae are unicellular Algae lack vascular tissues Most algae aquatic; most plants terrestrial
1 Problems of Land Plants Transporting water Developed vascular tissues (veins) Support Parenchyma cells – thin walls & usually remain alive after they become mature. Parenchyma forms the "filler" tissue in the soft parts of plants. Collenchyma cells - thin primary walls with some thickening of secondary wall. Provides extra structural support. Sclerenchyma cells - thick lignified secondary walls, often die when mature. Sclerenchyma provides the main structural support to a plant Dehydration Cuticle helps prevent loss of water Stomata control loss of water
Problems of Land Plants
Sexual reproduction Wind pollinated and insect pollinated flowers increased chances of reproduction Protection of embryo Ovary Seeds
4 Major Plant Groups
4 main groups of land plants: Bryophytes – mosses Tracheophytes – have veins Lycophytes – club mosses Pteridophytes – ferns Gymnosperms – pines & conifers Angiosperms – flowering plants
2 Bryophyta Tracheophyte ↓ ↓ Non-vascular Vascular Lycophytes Pteriphytes Gymnosperms Angiosperm
Spores Spores Naked seeds Enclosed seeds Non-flowering Flowering ↓ Monocot Dicot ↓ ↓
5 Evolutionary Events
Embryo protection - all plants protect their embryos Algae do not Mosses - lack vascular tissue but do protect their embryos Vascular tissue - Lycophytes For water transport, have true roots, stems, and leaves Megaphylls - Ferns Increases amount of photosynthesis and carbohydrates produced Seeds - Gymnosperms Contains embryo and stored organic nutrients inside a protective coat Flowers - Angiosperms Reproductive structure to attract pollinators and give rise to fruits
Alternation of generations All land plants show alternation of generations where 2 plants each produce the other. does not occur in the algae Gametophyte Haploid cells Produces gametes - (egg & sperm) Zygote undergoes mitosis to form sporophyte Sporophyte Diploid cells Produces haploid spores • Spore - reproductive cell that develops into new organism w/out the need to fuse with another reproductive cell
3 Alternation of generations life cycle
sporophyte (2n) Mitosis
zygote (2n) sporangium (2n)
diploid (2n) FERTILIZATION MEIOSIS haploid (n)
gametes (n) spore (n)
Mitosis Mitosis gametophyte (n)
Alternation of Generations
The dominant generation Generation that is larger, lasts longer, and is most visible Nonvascular plants - gametophyte dominant Vascular plants - sporophyte dominant •Gametophyte becomes smaller and dependent In the history of plants, only the sporophyte generation evolves vascular tissue.
4 Bryophytes
Bryophytes - nonvascular Lack true roots, stems, & leaves Gametophyte generation is dominant Sporophytes are smaller & present only part of the time Flagellated sperm must swim in water Only a few cm tall Represented by 3 phyla: liverworts hornworts Mosses Not every plant named “moss” is a bryophyte • Irish moss is an alga, Spanish moss is an angiosperm
Bryophytes - mosses
Mosses grow in damp, shaded locations Become dormant in dry seasons Bryophytes are anchored by rhizoids - small root like structures . They do not play a role in absorption
Bryophytes - Mosses
Sporophyte consist of the following: Stalk or seta Capsule or Sporangium – stores spores Operculum – lid of capsule Haploid spores are released that then form a gametophyte
5 Diversity of Plants Bryophytes have evolved several adaptations for life on land , but are not very successful. The other major groups of land plants evolved vascular tissue & are called Vascular plants.
Vascular tissues transport H 2O & nutrients thru the plant. Bryophytes lack water-conducting tubes & are referred to as “nonvascular plants.” Materials transported through diffusion
Tracheophytes
All plants with vascular tissues; EXCEPT Bryophytes Sporophyte is dominate generation Xylem – carries water &minerals upward Phloem – transports nutrients & stored food to roots & stems Have true roots to absorb water Have stems to transport materials Have leaves - photosynthesis
Tracheophytes All Tracheophytes are divided into 2 groups Seedless plants; spore produces Lycophytes and ferns Seed plants Gymnosperms and angiosperms
6 Pteridophytes
Pteridophytes, seedless vascular plants, (2 phyla) phylum Lycophyta - lycophytes phylum Pterophyta - ferns, whisk ferns, & horsetails
Pteridophytes
Most have true roots. Lycophytes have small leaves with a single unbranched vein. These leaves, called microphylls, probably evolved from tissue flaps on the surface of stems. Leaves of other vascular plants, megaphylls, are larger & have veins
Lycophytes
Lycophytes - sporangia strobili sporophyll club mosses Among first leaves Strobilus (microphylls) land plants to stoma have branches vascular tissue vascular tissue Small leaves Leaf called xylem phloem microphylls arial stem with single rhizome vein root Root
7 Pteridophytes Ferns Have megaphylls or fronds •Large leaves with branched veins •Immature leaves called fiddlehead Larger surface area for photosynthesis Better able to make food, grow, and reproduce Sporangia located in sori on the underside of fronds Small independent gametophyte Flagellated sperm; must have moist environment
Pteridophytes
Pteridophytes Horsetails – Often found in marshy habitats Roots develop from horizontal rhizomes that extend along the ground. Reproductive stems produce cones at their tips. Cones consist of clusters of sporophylls that produce sporangia w/haploid spores.
8 Pteridophytes The phyla Lycophyta & Pterophyta formed forest that later became fossil fuels in the form of coal. Known as “Coal Age Plants”
2 groups of seed plants
2 branches of seed plants- Gymnosperms & Angiosperms
Gymnosperm – naked seeds Angiosperm – enclosed seeds
NO WATER NEEDED FOR FERTILIZATION
Gymnosperms
Gymnosperms appears in the fossil record before angiosperms The ovules & seeds of gymnosperms (naked seeds) develop on the surfaces of specialized leaves called sporophylls. ovules & seeds of angiosperms develop in ovaries
9 Gymnosperms Phylum Coniferophyta - the largest gymnosperm group, include pines, firs, spruces, larches, junipers, cedars, cypresses, & redwoods, yews Amongst the largest & oldest organisms of Earth. Redwoods from northern California can grow to heights of over 100 m 1 bristlecone pine from California is more than 4,600 years old.
Gymnosperms
Most are evergreen, retain their leaves & photosynthesize throughout the year. Some conifers, (redwood & cypress) are deciduous Resin protects leaf from fungi & insect attack Needle-shaped leaves are adapted for dry conditions. A thick cuticle & the placement of stomata in pits helps reduce water loss
Angiosperms Angiosperms, flowering plants, are vascular seed plants that produce flowers & fruits. The most diverse, geographically widespread & most successful of all plants. All angiosperms are placed in the phylum Anthophyta.
10 Angiosperms Angiosperms are ÷ into 2 classes, monocots & dicots. Monocots have leaves with parallel veins, dicots have netlike venation. Monocots have fibrous root systems, dicots have tap roots Monocots have 1 cotyledon, dicots 2 Monocots include lilies, orchids, corn, yuccas, grasses, and grains. Dicots include fruit trees, vegetables
Angiosperms
Monocots usually herbaceous Dicots usually woody Monocot flower petals in sets of 3 Dicot flower petals in sets of 4 or 5
11 The Flower
The flower is specialized for reproduction The flower contributed to the success of angiosperms.
The Flower Receptacle –base of flower w/stem Sepal (calyx) -modified leaves at the base of the flower; enclose flower before it opens Petals (corolla) -lie inside the ring of sepals. Bright colors attract pollinators. Wind-pollinated plant typically lack bright colors. Neither the sepals or petals are involved in reproduction
The Flower Stamen - male reproductive organs A stamen consists of a filament (stalk) & the anther where pollen is produced. Carpels (pistils) are female reproductive organs. At the tip of the carpel is a sticky stigma that receives pollen. A style leads to the ovary at the base of the carpal. The swollen base is the ovary that will develop into the fruit Ovules (seeds) are protected within the ovary.
12 Fruits Fruit is the mature ovary As seeds develop from ovules after fertilization, the wall of the ovary thickens to form the fruit. Fruits protect dormant seeds In some plants the fruit functions like a kite or propeller, enhancing wind dispersal (maple) Many angiosperms use animals to carry seeds • Burrs cling to animal fur. • Edible fruits are eaten by animals & are deposited unharmed, along w/fertilizer.
Seeds The seed consists of the embryo, endosperm, & a seed coat As the ovules develop into seeds, the ovary develops into a fruit. After dispersal by wind or animals, a seed germinates if environmental conditions are favorable. During germination, the seed coat ruptures & the embryo emerges as a seedling. It uses the food stored in the cotyledons to support development.
13 Seed Structures
Seed coat – protection Cotyledon – stored food Hilum – scar where bean was attached to pod (belly button) Micropyle – small pore where water enters Embryo – baby plant Radicle – root Hypocotyl – stem Epicotyl – 1st leaves
Success of Plants Agriculture, the cultivation & harvest of plants, began about 10,000 yrs. ago Agriculture made possible the transition from hunter-gather societies to permanent settlements. The seeds of gymnosperms & angiosperms enhanced the ability of plants to survive & reproduce.
Human dependence We depend on plants for food production & oxygen. Flowering plants provide nearly all our food. Fruit, vegetables, corn, rice, & wheat are angiosperms. We also grow angiosperms for fiber, medications, perfumes,
14 The Fungi
Mycology – study of fungi Not plants—no chloroplasts; can’t photosynthesize Not animals—heterotrophs Animals ingest their food, fungi absorb it (chemoheterotrophs) Animals are motile, most fungi are not Fungi have windblown spores during both sexual & asexual life cycles
General Biology of a Fungus Hyphae - thin filaments of cells making up a fungus Mycelium - is mass of hyphae making up main body of fungus The mushroom or puffball one sees are not the main body of the fungi, only temporary reproductive structures The main body of a fungi is Michigan is 38 acres beneath the soil. (Humongous Fungus)
15 General Biology of a Fungus
Fungi have thick cell walls. Do not contain cellulose like plants Contain chitin, like exoskeleton of crabs and lobsters Septa or a wall divides the cells of a hyphae in many fungi Hyphae give mycelium large surface area for absorption of nutrients
Zygomycota
Black Bread Mold Stolen - horizontal hyphae on surface of bread Rhizoids – root like structures grow into the bread to anchor and carry out digestion Sporangiophore - stalk that bear sporangia Sporangium – spore case holding sporangia Sporangia - spores produced in asexual reproduction Sexual reproduction – 2 different mating types meet, tips of + and – hyphae join(conjugation), nuclei fuse, and a ZYGOSPORE results Zygospore germinates to produce sporangia Sporangia undergo meiosis to produce spores Spores give rise to new hyphae
Life cycle of black bread mold
thick-walled zygospore
zygote ×50
diploid (2n) Sexual NUCLEAR FUSION reproduction MEIOSIS
haploid (n) wind-blown spores (n)
sporangium
Asexual reproduction
Asexual reproduction
mycellum – mating type
16 Basidiomycota - Club Fungi
Mushrooms that one eats are fruiting body whose function is to produce spores The + and – hyphae join to form the mushroom fruiting body Mushroom has stalk and cap Basidia – club-like structures on the gills on underside of cap Basidiaspores – sexual spores
Ascomycota – Sac Fungi Ascus – cup shaped fruiting body Ascospores – sexual spores produced in ascus Conidiaspores – asexual spores produced from hyphae Similar life cycle to Club Fungi
17 Ecological Benefits of fungi Most fungi are saprotrophs Decompose remains of plants, animals, and microbes returning inorganic nutrients to soil Many are used to produce medicine Penicillium is used to produce the antibiotic penicillin Yeast is used in producing bread, beer, & other alcoholic drinks Soy sauce, cheeses and food itself
Mutualistic relationships
2 different species live together and help each other out Crustose lichen Lichens •Fungus & cyanobacteria or green algae •Fungus acquires
nutrients & moisture Fruticose lichen •Photosynthetic partner makes food
Foliose lichen
18 Mutualistic relationships
Mycorrhizal fungi Mutualistic relationships with roots of plants Help plants grow more successfully in dry or poor soils Hyphae increase surface area for absorption of food and nutrients Fungus and plant exchange nutrients
Fungi and Diseases
Mycoses – diseases caused by fungi Serious crop losses 1/3 of world rice crop destroyed by rice blast disease Potato blight in 1845 led to Irish immigration to US Corn smut Animal diseases Thrush or yeast infections – white patches on tongue Ringworm – red irritated rings on skin Athlete’s foot - red irritated skin on feet Histoplasmosis – from bird or bat droppings; causes flu like symptoms
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