Angiosperms The most advanced plant group Jaime Crosby, CHS

General Characteristics of Flowering Plants Largest and most diverse division of plants with over 250,000 species –Can live in all biomes from desert to frigid areas Definition: Seed in a vessel –The vessel is the carpel, the flower part that becomes the fruit –Thus the seed is no longer naked, but protected by a fruit Anything with a seed is a fruit Fruits: peppers, tomatoes, pumpkin, apples

Classification: 2 large classes Monocots –Leaves/petals in 3’s, one cotyledon (seed leaf), parallel leaf veins, monkey faces, no wood rings Dicots –Leaves/petals in 4’s or 5’s, two cotyledons, branched veins, ring of vascular bundles, possible tree rings

Views on origination Contemporary: believe angiosperms evolved independently from seed ferns, and the flower is a modified stem with modified leaf petals Traditional: believe angiosperms evolved from conifers and the flower is a modified cone

Life cycle of angiosperms… TREMENDOUS EVOLUTIONARY ADVANCEMENT… Structure of typical flower:

Sepals enclose flower bud before opening –All sepals = calyx Petals attract insects and act as a landing pad –All petals = corolla

Stamen = anther + filament –Inside the anther are the microsporangia in which pollen is produced

Pistil = Stigma + Style + Ovary –Female megagametophyte (ovule) is produced here, fertilization occurs here, fruit develops here

Pollination Self or cross pollination –Most flowers produce sperm/eggs at opposite times to avoid self- pollination Pollen grain lands on flower, form pollen tube toward ovary –Pollination by wind, water, insects, birds and animals

Double Fertilization: Each pollen grain contains 2 sperm; one sperm fuses with egg to form zygote, the other fuses with 2 polar nuclei to produce a triploid (3N) endosperm –Endosperm = food for the embryo in the seed

After fertilization, the seed forms, and the ovary wall thickens and becomes the fruit

The seed becomes dormant until conditions are right for germination The seed absorbs water and the embryo grows a primary root and a cotyledon which will become the shoot

2 Vocab words about Angiosperms Parthenocarpy: fruits from unfertilized eggs like seedless watermelon, etc. Co-evolution: When 2 organisms evolve structures in response to each other –Hummingbirds and trumpet vines –Barbs, sweet fruits, etc. Velcro

Pollination ecology… Vectors –Bees use flower nectar as primary nourishment Prefer blue and yellow flowers with honey guides which lead bees in Ultraviolet patterns on flowers visible to bees

Flies –Dull red/brown colors –Foul “carrion” odors Moths/Butterflies –White or yellow colors –Sweet fragrances Beetles –Flowers generally white or dull color –Strong yeasty, spicy or fruity odors

Birds –Flowers with bright red or yellow inflorescences that produce copious amounts of nectar –Tubular Bats –Tropical flowers that open at night with ball-like flowers

Orchid Adaptations to welcome bees Pollinia sacs contain pollen –Stick to back/neck Petals modified to resemble female bees –Males try to mate

Angiosperm Bingo CotyledonTriploidFruit ContemporaryTraditional MonocotDicotDispersal ParthenocarpyPetals SepalsPollen tube GerminationDouble Fert. PollinationYeasty, spicy CarrionYellow, blue, white, sweet PistilStigmaStyle OvaryStamenAnther FilamentCorollaCalyx 250,000VelcroIntegument EndospermCo-evolution