Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

Inside ovary:Inside ovary:Structures called Structures called ovulesovules. Meiosis occurs in . Meiosis occurs in these, producing four haploid female spores. these, producing four haploid female spores. Three of these disintegrate.Three of these disintegrate.The fourth spore divides 3x by mitosis The fourth spore divides 3x by mitosis eight eight nuclei in seven cells (one cell has two nuclei nuclei in seven cells (one cell has two nuclei called the called the polar nucleipolar nuclei). Another cell is the ). Another cell is the egg cellegg cell..

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

In the stamens:In the stamens:Anthers undergo meiosis Anthers undergo meiosis four haploid male spores.four haploid male spores.Each spore contains a haploid nucleus that divides by Each spore contains a haploid nucleus that divides by mitosis mitosis two nuclei.two nuclei.Spore wall thickens around each nucleus Spore wall thickens around each nucleus pollen pollen graingrain..Each pollen grain is a male gametophyte containing Each pollen grain is a male gametophyte containing two cells:two cells:

Tube cellTube cell (with one haploid nucleus)(with one haploid nucleus)Sperm cellSperm cell (which divides by mitosis to form two haploid (which divides by mitosis to form two haploid sperm nuclei).sperm nuclei).

Each anther can produce thousands of pollen grains.Each anther can produce thousands of pollen grains.

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)PollinationPollination: occurs with the transfer of pollen from stamens to : occurs with the transfer of pollen from stamens to

carpel (Figs. 22.6 & 22.7, pp. 669 carpel (Figs. 22.6 & 22.7, pp. 669 -- 71).71).Either between flowers of the same plant, or between plants of Either between flowers of the same plant, or between plants of same species.same species.Sticky stigma at top of carpel can trap pollen.Sticky stigma at top of carpel can trap pollen.When pollen lands on stigma, it germinates and the tube cell When pollen lands on stigma, it germinates and the tube cell develops into pollen tube, extending down style toward base of develops into pollen tube, extending down style toward base of ovule in ovary.ovule in ovary.Sperm nuclei are carried to ovule via pollen tube.Sperm nuclei are carried to ovule via pollen tube.One sperm nucleus unites with egg: One sperm nucleus unites with egg: fertilizationfertilization..The other sperm nucleus unites with polar nuclei, forming the The other sperm nucleus unites with polar nuclei, forming the triploidtriploid endospermendosperm, a nutrient, a nutrient--rich structure that nourishes the rich structure that nourishes the developing embryo inside the developing embryo inside the seedseed, which consists of the , which consists of the embryo plant, the endosperm and a protective coating ( p. 670).embryo plant, the endosperm and a protective coating ( p. 670).

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

Similarities between life cycles of mosses and Similarities between life cycles of mosses and flowering plantsflowering plants::Meiosis occurs just before spore formation.Meiosis occurs just before spore formation.Alternation of generations between Alternation of generations between sporophytesporophyteand gametophyte generations.and gametophyte generations.

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

DifferencesDifferences::Flowering plants donFlowering plants don’’t require great amounts of t require great amounts of water for fertilization.water for fertilization.Gametophytes of flowering plants are smaller Gametophytes of flowering plants are smaller than those of mosses.than those of mosses.Gametophyte that produces the egg and the Gametophyte that produces the egg and the spore that produces the gametophyte remain spore that produces the gametophyte remain attached to attached to sporophytesporophyte plant.plant.Embryo (young Embryo (young sporophytesporophyte) grows for short ) grows for short time, then becomes dormant (enclosed in time, then becomes dormant (enclosed in protective seed).protective seed).

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

Land plants illustrate trend toward Land plants illustrate trend toward increasing increasing specialization of the specialization of the sporophytesporophyte and and decreasing specialization of the gametophytedecreasing specialization of the gametophyte. . ((Fig. 22.7, p. 671Fig. 22.7, p. 671))

Flowering Plants (Angiosperms)Flowering Plants (Angiosperms)

In summaryIn summary, flowering plants are well adapted to , flowering plants are well adapted to terrestrial existence by:terrestrial existence by:Vascular tissueVascular tissueRoot systemsRoot systemsCuticleCuticleSperm carried in pollenSperm carried in pollenSpores protected on Spores protected on sporophytessporophytesEmbryos protected in seedsEmbryos protected in seeds

Many Flowering Plants Have Special Many Flowering Plants Have Special PollinatorsPollinators

Flowering plants/angiospermsFlowering plants/angiosperms ((phylumphylumAnthophytaAnthophyta):):FlowerFlower = reproductive structure of the plant.= reproductive structure of the plant.PollinatorsPollinators: insects, birds, bats, other animals.: insects, birds, bats, other animals.Wind can also transport pollen.Wind can also transport pollen.

Many Flowering Plants Have Special Many Flowering Plants Have Special PollinatorsPollinators

CrossCross--pollinationpollination: : pollen from one plant is pollen from one plant is transferred to carpel of another plant.transferred to carpel of another plant.SelfSelf--pollinationpollination: : pollen from flower falls on pollen from flower falls on stigma of same flower.stigma of same flower.

Many plants have evolved devices to prevent this Many plants have evolved devices to prevent this from occurring.from occurring.

Many Flowering Plants Have Special Many Flowering Plants Have Special PollinatorsPollinators

Sepals and petals = Sepals and petals = ““sterile seriessterile series,,”” as they do as they do not directly participate in reproduction.not directly participate in reproduction.

Act as protection for developing reproductive Act as protection for developing reproductive structuresstructuresFunction as pollinator attractantsFunction as pollinator attractants

Stamens and pistils (Stamens and pistils (carpelscarpels) = ) = ““fertile seriesfertile series””

Many Flowering Plants Have Special Many Flowering Plants Have Special PollinatorsPollinators

Variety of flower structure is related to various Variety of flower structure is related to various means by which pollination occurs.means by which pollination occurs.

Insect pollinationInsect pollination: flower large and brightly : flower large and brightly colored, possessing small colored, possessing small nectarnectar (sugar solution) (sugar solution) glands (glands (nectarynectary).).Wind pollinationWind pollination: flower has small sepals and : flower has small sepals and petals, or none at all; flower positioned high on petals, or none at all; flower positioned high on plant; produce a lot of pollen; plant; produce a lot of pollen; carpelscarpels with long, with long, feathery structures with sticky fluid at tips for feathery structures with sticky fluid at tips for catching pollen.catching pollen.

Many Flowering Plants Have Special Many Flowering Plants Have Special PollinatorsPollinators

CoevolutionCoevolution: mutual evolutionary influence between two species, : mutual evolutionary influence between two species, e.g. flowers and insects, or flowers and hummingbirds.e.g. flowers and insects, or flowers and hummingbirds.Hummers do not have wellHummers do not have well--developed sense of smell, but can developed sense of smell, but can see color red very well.see color red very well.Flowers pollinated by hummers are typically red, with abundant Flowers pollinated by hummers are typically red, with abundant nectar at base of long tube formed by petals.nectar at base of long tube formed by petals.

Makes it difficult for other species to rob nectar from flower.Makes it difficult for other species to rob nectar from flower.Hummers, with long beaks and tongues, can reach nectar.Hummers, with long beaks and tongues, can reach nectar.

Hummingbird head is dusted with pollen when it visits flower Hummingbird head is dusted with pollen when it visits flower for nectar.for nectar.When bird visits female flower, the carpel is positioned so When bird visits female flower, the carpel is positioned so pollen is scraped onto carpel from hummerpollen is scraped onto carpel from hummer’’s head.s head.Both species benefit.Both species benefit.

Flowering Plants Produce Fruits with Flowering Plants Produce Fruits with SeedsSeeds

After pollination and fertilization, seed begins After pollination and fertilization, seed begins to develop.to develop.Depending on plant, may be many seeds from Depending on plant, may be many seeds from one flower (one flower (compound ovarycompound ovary).).Plant embryo is protected within seed; seed is Plant embryo is protected within seed; seed is protected within fruit.protected within fruit.

Flowering Plants Produce Fruits with Flowering Plants Produce Fruits with SeedsSeeds

Inside the seedInside the seed::CotyledonsCotyledons: modified leaves; : modified leaves; ““seed leavesseed leaves””(either one or two) that are part of the (either one or two) that are part of the developing embryo.developing embryo.EndospermEndosperm: food supply for developing : food supply for developing embryo.embryo.Cells that will form the root.Cells that will form the root.

Flowering Plants Produce Fruits with Flowering Plants Produce Fruits with SeedsSeeds

Examples of seedsExamples of seeds::Beans and peasBeans and peas

Examples of fruitExamples of fruit::Apples and oranges (both of which have many Apples and oranges (both of which have many seeds)seeds)TypicallyTypically, the fruit will decay or be eaten by , the fruit will decay or be eaten by some animal, which will deposit the seeds some animal, which will deposit the seeds elsewhere to germinate.elsewhere to germinate.

Flowering Plants Are the Most Diverse Flowering Plants Are the Most Diverse Group of Land PlantsGroup of Land Plants

Plants vary in size and in the life spans of their Plants vary in size and in the life spans of their shootsshoots(above(above--ground parts).ground parts).TreesTrees: leaves are high above ground to receive : leaves are high above ground to receive abundant sunlight.abundant sunlight.

Can store large amounts of food reserves in trunk and roots.Can store large amounts of food reserves in trunk and roots.Allows them to survive through bad years.Allows them to survive through bad years.Long life spans.Long life spans.

Flowering PlantsFlowering Plants

Most flowering plants are not trees.Most flowering plants are not trees.May be woody shrubs, e.g. roses and raspberriesMay be woody shrubs, e.g. roses and raspberriesMay be woody vines, e.g. grapes and othersMay be woody vines, e.g. grapes and others

Most are Most are herbaceousherbaceous plants: nonplants: non--woody (woody (Fig. 20.17, Fig. 20.17, p. 627p. 627))

Flowering PlantsFlowering Plants

Flowering plants are divided into two classes (Flowering plants are divided into two classes (Fig. 20.16, Fig. 20.16, p. 626p. 626):):

1.1. MonocotsMonocots2.2. DicotsDicots

13.11 Flowering Plants13.11 Flowering PlantsMonocots (monocotyledons)Monocots (monocotyledons)::

Fig. 20.16, p. 626Fig. 20.16, p. 626Embryo contains a single Embryo contains a single cotyledoncotyledon (seed(seed--leaf)leaf)Floral parts in multiples of three (3)Floral parts in multiples of three (3)Leaves with parallel veinsLeaves with parallel veinsIncludes grasses and grains such as wheat, rice and Includes grasses and grains such as wheat, rice and corn (all of which are major food plants of the corn (all of which are major food plants of the world)world)

13.11 Flowering Plants13.11 Flowering Plants

13.11 Flowering Plants13.11 Flowering PlantsDicotsDicots ((dicotyledonsdicotyledons))::

Embryo contains two cotyledonsEmbryo contains two cotyledonsLarger class than monocotsLarger class than monocotsFloral parts in multiples of four or five (4 or 5)Floral parts in multiples of four or five (4 or 5)Leaves with branching veinsLeaves with branching veinsIncludes most fruits and vegetables, e.g. Includes most fruits and vegetables, e.g. carrots, lettuce, apples and grapes, as well as carrots, lettuce, apples and grapes, as well as hardwood treeshardwood trees

13.11 Flowering Plants13.11 Flowering Plants

PhotosynthesisPhotosynthesis

PhotosynthesisPhotosynthesis

PhotosynthesisPhotosynthesis

Occurs in the Occurs in the chloroplastschloroplasts of plants.of plants.

PhotosynthesisPhotosynthesis

Energy source used by Energy source used by photoautotrophsphotoautotrophs can never be can never be exhausted.exhausted.LightLight = vibrating electric and magnetic field; acts = vibrating electric and magnetic field; acts like a wave.like a wave.

WavelengthWavelength ((λλ) determines the light) determines the light’’s color and energys color and energyShorter Shorter λλ: greater energy: greater energyLonger Longer λλ: less energy: less energy

Visible lightVisible light = just one narrow section of the = just one narrow section of the electromagnetic (EM) spectrumelectromagnetic (EM) spectrumUV lightUV light: higher energy than visible range of light; : higher energy than visible range of light; few organisms have evolved to use this range of light few organisms have evolved to use this range of light for energy without being harmed by it.for energy without being harmed by it.

Electromagnetic SpectrumElectromagnetic Spectrum

PhotosynthesisPhotosynthesis

Photoautotrophic cells have evolved an ability Photoautotrophic cells have evolved an ability to capture some of the energy from the visible to capture some of the energy from the visible light spectrum via lightlight spectrum via light--absorbing substances absorbing substances called called pigmentspigments..

PhotosynthesisPhotosynthesis

ChlorophyllChlorophyll: the green pigment found in the : the green pigment found in the thylakoidsthylakoids which absorbs light.which absorbs light.

PhotosynthesisPhotosynthesisTwo types of chlorophyll: Two types of chlorophyll: aa and and bb..

They both absorb light in the violet/blue and orange/red They both absorb light in the violet/blue and orange/red ranges.ranges.Reflect green lightReflect green light

PhotosynthesisPhotosynthesisIn fall, as chlorophyll In fall, as chlorophyll content in leaves content in leaves declines, other, declines, other, accessory pigments accessory pigments become increasingly become increasingly visible.visible.Some photosynthetic Some photosynthetic bacteria contain bacteria contain rhodopsinrhodopsin, a light, a light--absorbing protein, absorbing protein, instead of chlorophyll.instead of chlorophyll.

PhotosynthesisPhotosynthesisTwo groups of reactions by which photosynthesis takes place:Two groups of reactions by which photosynthesis takes place:

Section 4.3, pp. 108 Section 4.3, pp. 108 -- 1121121.1. Light reactionsLight reactions: during which light: during which light--absorbing pigments in absorbing pigments in

the the thylakoidsthylakoids absorb light and convert it to chemical energy absorb light and convert it to chemical energy carried by shortcarried by short--lived, energylived, energy--rich molecules.rich molecules.

2.2. Calvin cycleCalvin cycle: A series of reactions by which sugars are : A series of reactions by which sugars are synthesized from those energysynthesized from those energy--rich molecules.rich molecules.The products of the light reactions are used in the Calvin The products of the light reactions are used in the Calvin Cycle.Cycle.The reactions of photosynthesis may be summarized by the The reactions of photosynthesis may be summarized by the following chemical equation:following chemical equation:

3 CO3 CO22 + 3 H+ 3 H22O O CC33HH66OO33 + 3 O+ 3 O22..

PhotosynthesisPhotosynthesis

PhotosynthesisPhotosynthesis

Light ReactionsLight Reactions ((Fig. 4.7, p. 109Fig. 4.7, p. 109))Chlorophyll and other pigments absorb light Chlorophyll and other pigments absorb light energy.energy.

PhotosynthesisPhotosynthesisLight ReactionsLight Reactions ((Fig. 4.7, p. 109Fig. 4.7, p. 109))

Water is split into hydrogen and oxygen.Water is split into hydrogen and oxygen.Light energy is converted to chemical energy.Light energy is converted to chemical energy.Product of the light reactions: chemical energy that Product of the light reactions: chemical energy that will power the Calvin cycle.will power the Calvin cycle.

PhotosynthesisPhotosynthesisLight Reactions:Light Reactions:

PhotosynthesisPhotosynthesis

Light reactions in summary:Light reactions in summary:Light forces electrons to flow from water to Light forces electrons to flow from water to NADPNADP++ in the chloroplast. Electrons retain in the chloroplast. Electrons retain this energy in NADPH.this energy in NADPH.Some of the NADPH is used to synthesize Some of the NADPH is used to synthesize ATP.ATP.Thus, light energy is converted to two forms of Thus, light energy is converted to two forms of chemical energy: ATP and NADPH. This chemical energy: ATP and NADPH. This energy will then be used to make sugars from energy will then be used to make sugars from carbon dioxide.carbon dioxide.

PhotosynthesisPhotosynthesis

The Calvin CycleThe Calvin Cycle::Fig. 4.9, p. 111Fig. 4.9, p. 111Completes the process of photosynthesis.Completes the process of photosynthesis.Converts the chemical energy of NADPH and ATP Converts the chemical energy of NADPH and ATP into sugars.into sugars.The various steps by which this occurs are catalyzed The various steps by which this occurs are catalyzed by enzymes.by enzymes.Occurs in the Occurs in the stromastroma of the chloroplast.of the chloroplast.

PhotosynthesisPhotosynthesis

The Calvin The Calvin CycleCycle::

PhotosynthesisPhotosynthesis

PhotosynthesisPhotosynthesis

Ch. 20 OutlineCh. 20 Outline

Plants (Kingdom Plants (Kingdom PlantaePlantae))I.I. NonNon--vascular plantsvascular plants

1.1. Liverworts (phylum Liverworts (phylum HepaticophytaHepaticophyta))2.2. Hornworts (phylum Hornworts (phylum AnthocerotophytaAnthocerotophyta))3.3. True mosses (phylum True mosses (phylum BryophytaBryophyta))

Ch. 20 OutlineCh. 20 OutlineII.II. Vascular plantsVascular plants

1.1. Non seedNon seed--producingproducinga.a. Whiskfern (phylum Whiskfern (phylum PsilophytaPsilophyta))b.b. Club mossesClub mosses (phylum(phylum LycophytaLycophyta))c.c. HorsetailsHorsetails (phylum(phylum SphenophytaSphenophyta))d.d. FernsFerns (phylum (phylum PterophytaPterophyta))

2.2. SeedSeed--producingproducinga.a. Gymnosperms/conifers (naked seeds in cones): includes pines, firGymnosperms/conifers (naked seeds in cones): includes pines, firs, s,

spruces, ginkgos, cycads.spruces, ginkgos, cycads.i.i. Pines, firs, sprucesPines, firs, spruces (phylum(phylum ConiferophytaConiferophyta: : ““conecone--bearingbearing””))ii.ii. Ginkgos (phylumGinkgos (phylum GinkgophytaGinkgophyta))iii.iii. Cycads (phylumCycads (phylum CycadophytaCycadophyta))

b.b. Angiosperms/flowering plants (phylum Angiosperms/flowering plants (phylum AnthophytaAnthophyta: seeds : seeds enclosed in fruit)enclosed in fruit)i.i. MonocotsMonocotsii.ii. DicotsDicots