Seed Plants

Seed PlantsGymnosperms &Angiosperms1

Quick Defs Vascular xylem and phloem– Xylem Brings water/nutrients fromroots to the plant.– Phloem Brings sugars down from theleaves2

Evolution Of Land PlantsREMEMBER: Terrestrial plants evolved from agreen algal ancestor The earliest land plants werenonvascular, spore producers(bryophytes) Ferns were the 1st vascular, sporeproducing plants Gymnosperms & angiosperms werethe 1st vascular, seed plants3

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Characteristics of Seed Plants MulticellularAutotrophicReproduce by SeedsVascular tissue fortransport Heterosporous –make femalemegaspores & malemicrospores5Dandelion dispersing seeds

Reasons for Success on Land Waxy cuticle Stomata with guard cells to open &close Seeds protect developing embryo &contain food6

Seeds Seeds contain a young,developing plant embryo Seeds are covered with aprotective seed coat (testa)7

Seed Dispersal Seeds must bescattered (dispersed)away from the parentplant Testa (seed coats)may last thousands ofyears Seeds eaten byanimals aren’t digestedbut pass out withwastes8

Seed Dispersal Seeds may have adaptations such asstickers, hooks, or fuzz to adhereto animals9

Seed Dispersal Both water andwind can scatterseedsWindDispersalWater Dispersal10

Seed Dispersal Methods11

Gymnosperms andAngiosperms Gymnosperm– Intro and evolution– Life cycle andreproduction– Uses and significance Angiosperms:Flowering plants– Intro and evolution– Life cycle andreproduction– Uses and significance– Monocots vs. dicots12

GYMNOSPERMS Introduction – Gymnosperm means “nakedseed” (From the Greek: gymnos naked;sperm seed) More advanced than ferns – do not havespores, they have seeds. The seeds of the gymnosperms lack aprotective enclosure (unlike floweringplants which have flowers and fruit). Examples of gymnosperms: Conifers (pine trees), cycads,13ginkgo biloba

Conifers Conifers adapted to temperate to coldregions Narrow leaves (needles) help to conservewater Covered by resins – for protection frompredators, fire, etc.14

Other gymnosperms Cycads – short shrubs,native to tropical regions(look like palms) Ginkgo biloba –a “living fossil”,male and female tree,used as a medicinal plant15

Significance of gymnosperms Ecological importance:Provide food and habitat for wildlifeForests prevent soil erosionReduce greenhouse-effect gassesEconomic and commercial importance:Lumber for wood, paper, etc.Resins – wood, furniture, etc.Ornamental plants (trees, landscaping)Food – pine nuts (pesto, etc.)16

ANGIOSPERMS Angiosperm means “covered seed”Have flowersHave fruits with seedsLive everywhere – dominant plants in theworld 260,000 species (88% of Plant Kingdom) Angiosperms are the most successful andadvanced plants on earth17

Evolution of Angiosperms Advancements over gymnosperms: Angiosperms have flowers – many usepollinators Fruits and seeds – adapted for dispersal18

Monocot vs. dicot Angiosperms are divided into monocotsand dicots As the zygote grows into the embryo,the first leaves of the young sporophytedevelop and are called as cotyledons(seed leaves) Monocots have one cotyledon (corn, lily,etc). Dicots have two cotyledons (bean, oak,19etc).

Monocot vs. dicot Number of cotyledons: one vs. two20

Monocot vs. dicot Leaf venation pattern: Monocot is parallel Dicot is net pattern21

Monocot vs. dicot root Monocot: Fibrous root Dicot: Tap root22

Reproduction of Angiosperms:* Pollination Pollen falls on a stigma when wind, bees, orbats carry it. (Sugar-rich nectar in the flower attracts beesor bats.)* Fertilization sperm & egg join together in the flower’sovule.- The zygote develops into the embryo part of theseed.- The ovary around the seed develops into a fruit.(Apples, cherries, tomatoes, squash, etc. are all fruit.)* Dispersal – animals eat the fruit and the seeds come outthe other end.23

Life Spans of Angiosperms:* Annuals complete a life cycle in one year.(pansies, wheat, tomatoes, cucumbers, etc)* Biennials complete life cycle in two years.(Second year they produce flowers and seeds.)(Parsley, celery, etc)* Perennials live for more than two years(Oak tree, honeysuckles, etc)(Roots and stems survive the winter)24

Modified from cmassengale25

3 Evolution Of Land Plants REMEMBER: Terrestrial plants evolved from a green algal ancestor The earliest land plants were nonvascular, spore producers (bryophytes) Ferns were the 1st vascular, spore producing plants Gymnosperms & angios