Ch.25 I.pdf

Chapter 25: Angiosperms Chapter 25 Learning Objectives ❖ ❖ ❖ ❖ ❖ ❖ Summarize the features that distinguish flowering plants from gymnosperms Describe the ecological and economic significance of flowering plants. Distinguish between monocots and eudicots. Be able to give examples of each. Discuss som...

Chapter 25: Angiosperms Chapter 25 Learning Objectives ❖ ❖ ❖ ❖ ❖ ❖ Summarize the features that distinguish flowering plants from gymnosperms Describe the ecological and economic significance of flowering plants. Distinguish between monocots and eudicots. Be able to give examples of each. Discuss some evolutionary adaptations of flowering plants. Distinguish between basal angiosperms and core angiosperms. Briefly describe and distinguishing characteristics of the following flowering plant families. Be able to give plant examples from each. BIO 1010 Chapter 9: Flowers, Fruits, and Seeds Chapter 9 Learning Objectives ❖ ❖ ❖ ❖ ❖ ❖ ❖ Name the parts of a flower and describe the functions of each part. Distinguish between pollination and fertilization. Compare the general characteristics of flowers pollinated in different ways. Define coevolution and give examples of way in which plants and their animal pollinators have affected one another’s evolution. List and define the main parts of a seed. Distinguish among simple, aggregate, multiple and accessory fruits; give examples of each type and cite several different methods of seed and fruit dispersal. Summarize the influence of environmental factors on seed germination. Angiosperms – The Flowering Plants ❖ Phylum Anthophyta (Magnoliophyta): Flowering Plants ❖ Largest Phylum ❖ Heterosporous ❖ Sporophytes dominant and independent Female gametophytes wholly enclosed within and dependent on sporophyte Microspores are released to become mature male gametophytes following pollination. Important Adaptations Basal Angiosperms Proposed Plant Evolution Basal Angiosperms ❖ Amborella trichopoda 2nd oldest group – water lilies 3rd oldest group – star anise Magnoliids Monocotyledones (Monocots) Eudicotyledones (Eudicots) Differences Between Eudicots and Monocots Eudicots Monocots Two cotyledons One cotyledon Flower parts in multiples of four or five Flower parts in multiples of three Leaves with distinct network of veins Leaves with parallel primary veins Vascular cambium and cork cambium present Vascular cambium and cork cambium absent Vascular bundles of stem in ring Vascular bundles of stem scattered Pollen grains with three apertures Pollen grains with one aperture Monocots and Eudicots 15 Generalized Flower Morphology (b) Cutaway view of an Arabidopsis flower. Each flower has four sepals (two are shown), four petals (two are shown), six stamens, and one pistil. Fig. 9-1b, p. 177 Generalized Flower Morphology (Whorls) pistil 18 ❖ Seeds enclosed in carpel that resembles a leaf that has folded over and fused at the margins. ❖ Pistil composed of a single carpel, or two or more united carpels. Seed develops from ovule within carpel and ovary becomes a fruit. Development of the Female Gametophyte Development of the Female Gametophyte Development of the Male Gametophyte Anther with microspores Development of the Male Gametophyte Colorized SEM Angiosperm Pollen Grains Angiosperms – The Flowering Plants Mature male gametophyte = germinated pollen grain with its vegetative nucleus and two sperms within tube cell (a) Development of a male gametophyte (in pol l en grain) (b) Development of a female gametophyte (embryo sac) Microsporangiu (pollen sac) Megasporangium (211) Microsporocyte (2n)......- Integuments (2n) MEIOSIS 1. 4 microspores (n) Megasporocyte (211) Micropyle ,..._,.Survivin g megaspore (n) Generative cell (n) MITOSIS 3 antipodal cell s (11) Male gametophyte rn \-i........ - 2 polar nuclei (n) 1 egg (n) 2 synergids (n) lliiilaii Ragweed pollen grain Female Gametophyte (n) (embryo sac) Eachof4 microspores (n) Angiosperms – The Flowering Plants ❖ Pollination: Transfer of pollen grains from anther to stigma Pollination by insects, wind, water, animals or gravity. Self-pollination VS. Cross-pollination Can lead to fertilization n E Plant Cycles ❖ Plant Cycle = from seed germination to mature plant producing seeds Annual plants - Cycle completed in single season. Biennial plants - Cycle completed in two growing seasons. Perennial plants - Cycle takes several to many growing seasons or plant produces flowers on new growth, while other plant parts persist indefinitely. Short-lived, long-lived Angiosperms: The Flowering Plants: Apomixis ❖ Apomixis – clonal reproduction without fusion of gametes but with the normal structures otherwise being involved – Embryo from diploid nutritive cell or other diploid cell of ovule, instead of from zygote. o Results in a vegetative propagated plant Bryophyllum daigremontianum Vegetative apomixis in Poa bulbosa; bulbils form instead of flowers Angiosperms – The Flowering Plants Parthenocarpy - Fruits develop from ovaries with unfertilized eggs. – Results in seedless fruits (Navel oranges & bananas) Angiosperms Part 2: Flower Specializations Generalized Flower Morphology (Whorls) pistil 38 Angiosperms – The Flowering Plants ❖ ❖ Trends of specialization and classification in flowering plants: Specialized flowering plants: Flower parts fewer and definite in number. Spiral arrangements compressed to whorls Bilaterally symmetrical flowers = irregular Reduction and fusion of parts – Incomplete or imperfect flowers Inferior ovary Orchid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Other Flower Terminology Term Type ofFlower Complete AlI four parts (sepals, petals, stamens, and carpels) present Incomplete Lacks one or more of the four parts Perfect Has both stamens and (a) carpel(s) Imperfect Has stamens or (a) carpel(s), but not both Inflorescence A cluster of flowers Composite Appears to be a single flower but consists of a group of tiny flowers Complete Flower Incomplete Flower Perfect Flowers: Hibiscus Flowers Pistil with swollen Stigma Stamen (anthers in yellow) Imperfect Flowers Squash Flowers Staminate Flower (male) Pistillate Flower (female) Superior versus Inferior Ovaries Hypanthium - a cup-shaped or tubular body formed by the conjoined sepals, petals, and stamens. Hypogynous (superior ovary) Perigynous (superior ovary) Cherry (Prunus sp.) Epigynous (inferior ovary) Zucchini (Cucurbita pepo) Flower Inflorescences – arrangement of flower heads or clusters Copy,,tgM one McGraw-HIii comp anlea, Inc. 1P m1 alon required for reproaucuon or display. simple umbea Composite Rudbeckia sp. Raceme Catkin Alder False So omon's seal Smtlacina ,acemosa ge aniu Pela gonium sp. Tansy Tanacetum vulgare Corymb Water hemlock Cicu asp. Compo nd umbel Fireweed £pilobium angustifolium compou d umbel · chasium d From MooNt, Clark, and Vodopich, , Botany, 2nd edition.c 1H8 The McGraw HmCompanie. All ri h18 reeerved. Inflorescence: Composite Flower – composed of ray and disc flowers in one flower head Asters (Family Asteraceae) Sexual Manipulators and Drug Dealers – UV Spectrum Nectar (maybe) – Drugs o Pheromones and Fragrance « Violence! Pollination Ecology ❖ Pollinators have coevolved with plants. Twenty thousand bee species among current-day pollinators. Bee-pollinated flowers: – – Generally brightly colored, mostly blue or yellow Often have lines or other distinctive markings, which may function as honey guides to lead bees to nectar. o Bees see UV light (humans do not). « Some flower markings visible only in UV light. In ordinary light In UV light Vegas Baby! ❖ UV Spectrum Vegas Baby! ❖ UV Spectrum Vegas Baby! ❖ UV Spectrum Pollination Ecology ❖ Beetle-pollinated flowers: Strong, yeasty, spicy or fruity odor White or dull in color - Beetles do have keen visual senses. Some do not secrete nectar, but furnish pollen or food on petals in special storage cells. Pollination Ecology ❖ Fly-pollinated flowers: Smell like rotten meat Dull red or brown Odiferous Botanical Trickery! ❖ Pelican Plant (Aristolochia grandiflora) Odiferous Botanical Trickery! ❖ Dead Horse Aurum (Helicodiceros muscivorus) Smells of rotting flesh Lay eggs that never get to become a blowfly Thermal Botanical Trickery! ❖ Arum or Corpse Flower (Amorphophallus titanum) Warm blooded?? Thermal Botanical Trickery! ❖ A Brazilian philodendron (Philodendron bipinnatifidum ) Warm blooded??