the plant kingdom: flowering plants chapter 25. learning objective 1 summarize the features that...
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LEARNING OBJECTIVE 1LEARNING OBJECTIVE 1
• Summarize the features that Summarize the features that distinguish distinguish flowering plantsflowering plants from from gymnospermsgymnosperms
KEY TERMSKEY TERMS
• ANGIOSPERM ANGIOSPERM • Traditional name for flowering plantsTraditional name for flowering plants• A large, diverse phylum of plants that form A large, diverse phylum of plants that form
flowers for sexual reproduction and produce flowers for sexual reproduction and produce seeds enclosed in fruitsseeds enclosed in fruits
Flowering PlantsFlowering Plants
• Like gymnosperms:Like gymnosperms:• Flowering plants have vascular tissues and Flowering plants have vascular tissues and
produce seeds produce seeds
• Unlike gymnosperms:Unlike gymnosperms:• OvulesOvules of flowering plants are enclosed within of flowering plants are enclosed within
an an ovaryovary
KEY TERMSKEY TERMS
• OVULE OVULE • Structure in the ovary that contains a female Structure in the ovary that contains a female
gametophyte and develops into a seed after gametophyte and develops into a seed after fertilization fertilization
• OVARY OVARY • Base of a carpel or fused carpels that Base of a carpel or fused carpels that
contains ovules and develops into a fruit after contains ovules and develops into a fruit after fertilizationfertilization
LEARNING OBJECTIVE 2LEARNING OBJECTIVE 2
• Describe the ecological and economic Describe the ecological and economic significance of the flowering plantssignificance of the flowering plants
Ecology and EconomyEcology and Economy
• Our survival as a species depends on Our survival as a species depends on flowering plants flowering plants • Major food cropsMajor food crops
• Products Products • Cork, rubber, tobacco, coffee, chocolate, Cork, rubber, tobacco, coffee, chocolate,
aromatic oils for perfumes aromatic oils for perfumes • Valuable lumberValuable lumber• Fibers and medicinesFibers and medicines
Economic BotanyEconomic Botany
• Subdiscipline of botany that deals with Subdiscipline of botany that deals with plants of economic importanceplants of economic importance• Most of these are flowering plantsMost of these are flowering plants
LEARNING OBJECTIVE 3LEARNING OBJECTIVE 3
• Distinguish between Distinguish between monocotsmonocots and and eudicotseudicots, the two largest classes of , the two largest classes of flowering plantsflowering plants
• Give specific examples of each classGive specific examples of each class
KEY TERMSKEY TERMS
• COTYLEDON COTYLEDON • The seed leaf of a plant embryo, which may The seed leaf of a plant embryo, which may
contain food stored for germinationcontain food stored for germination
KEY TERMSKEY TERMS
• MONOCOTMONOCOT • One of two main classes of flowering plants; One of two main classes of flowering plants;
monocot seeds contain a single monocot seeds contain a single cotyledoncotyledon • Monocots have floral parts in threes Monocots have floral parts in threes • Monocots include grasses, orchids, irises, Monocots include grasses, orchids, irises,
onions, lilies, palmsonions, lilies, palms
KEY TERMSKEY TERMS
• EUDICOT EUDICOT • One of two main classes of flowering plants; One of two main classes of flowering plants;
eudicot seeds contain two eudicot seeds contain two cotyledonscotyledons • Eudicots have floral parts in fours or fivesEudicots have floral parts in fours or fives• Eudicots include oaks, roses, mustards, cacti, Eudicots include oaks, roses, mustards, cacti,
blueberries, sunflowersblueberries, sunflowers
(a) Monocots, such as this nodding trillium(Trillium cernuum), have their floral parts in threes.Note the three green sepals, three white petals, sixstamens, and three stigmas (the compound pistilconsists of three fused carpels).
Stigmas ofpistil
Anther ofstamen
Sepal
Petal
Fig. 25-2a, p. 488
(b) Most eudicots such as this Tacitusbellus have floral parts in fours or fives.Note the five petals, 10 stamens, and fiveseparate pistils. Five sepals are also presentbut barely visible against the background.
Pistils
Anther ofstamen
Petal
Fig. 25-2b, p. 488
LEARNING OBJECTIVE 4LEARNING OBJECTIVE 4
• Briefly explain the Briefly explain the life cyclelife cycle of a of a flowering plantflowering plant
• Describe Describe double fertilizationdouble fertilization
Life CycleLife Cycle
• Flowering plants undergo an alternation of Flowering plants undergo an alternation of generations:generations:• Sporophyte generation is larger and Sporophyte generation is larger and
nutritionally independentnutritionally independent• Gametophyte generation is reduced to only a Gametophyte generation is reduced to only a
few microscopic cells few microscopic cells
KEY TERMSKEY TERMS
• DOUBLE FERTILIZATIONDOUBLE FERTILIZATION • A process in the flowering plant life cycle in A process in the flowering plant life cycle in
which there are two fertilizations which there are two fertilizations • One results in formation of a zygote One results in formation of a zygote • Second results in formation of Second results in formation of endospermendosperm
KEY TERMSKEY TERMS
• ENDOSPERMENDOSPERM • The 3The 3nn nutritive tissue formed at some point in nutritive tissue formed at some point in
the development of all angiosperm seedsthe development of all angiosperm seeds
Flower of maturesporophyte
Seedling
Fruit
Seed coatSeed
Embryo
Zygote (2n)
Endosperm (3n)
Anther
Megasporangium(ovule)
Megaspore mother cell
Ovary DIPLOID (2n)SPOROPHYTEGENERATION
HAPLOID (n)GAMETOPHYTEGENERATION
MegasporeEggnucleus
Double fertilization
Two spermcells
Pollentube
Polarnuclei
Embryo sac (maturefemale gametophyte)
Developing pollentube of maturemale gametophyte
Pollination
Pollen grain(immature malegametophyte)
Each microsporedevelops into apollen grain
Microspore
Tetrad ofmicrospores
Microspore mothercells withinmicrosporangia
Meiosis
1
24
56
3
8
7
Fig. 25-3, p. 490
LEARNING OBJECTIVE 5LEARNING OBJECTIVE 5
• Discuss some of the evolutionary Discuss some of the evolutionary adaptations of flowering plantsadaptations of flowering plants
Adaptations of Flowering Plants 1Adaptations of Flowering Plants 1
• Reproduce sexually by forming flowersReproduce sexually by forming flowers
• Form seeds within fruits Form seeds within fruits after double after double fertilizationfertilization
Adaptations of Flowering Plants 2 Adaptations of Flowering Plants 2
• Have efficient water-conducting Have efficient water-conducting vessel vessel elementselements in xylem and carbohydrate-in xylem and carbohydrate-conducting conducting sieve-tube elementssieve-tube elements in in phloemphloem
• Have pollen grains transported by wind, Have pollen grains transported by wind, water, insects, other animalswater, insects, other animals
KEY TERMSKEY TERMS
• APOMIXISAPOMIXIS • A type of reproduction in which fruits and A type of reproduction in which fruits and
seeds are formed asexually seeds are formed asexually
LEARNING OBJECTIVE 6LEARNING OBJECTIVE 6
• Trace the evolution of flowering plants Trace the evolution of flowering plants from gymnosperms from gymnosperms
Evolution of Flowering PlantsEvolution of Flowering Plants
• Probably descended from ancient Probably descended from ancient gymnosperms with specialized featuresgymnosperms with specialized features• leaves with broad, expanded blades and leaves with broad, expanded blades and
closed carpelsclosed carpels
• Probably arose only onceProbably arose only once
(a) The carpel resembles a foldedleaf in which the ovules borne onits upper surface are enclosed.
(b) A cross section of thecarpel, cut along the dashedline in (a).
Stigma
Style
Ovary
Ovules
Stigma
Fusedmargin
Carpel
Fig. 25-6, p. 493
(a) The oldest known fossil angiosperm. This fossil ofthe extinct plant Archaefructus shows a carpel-bearingstem. It was discovered in northeastern China and isabout 125 million years old.
(b) The fossilized flower of the extinct plant Archaeanthuslinnenbergeri, which lived about 100 mya. Thescars on the reproductive axis (receptacle) may showwhere stamens, petals, and sepals were originallyattached but abscised (fell off). Many spirally arrangedpistils were still attached at the time this flower wasfossilized.
Ovule
Carpel
Scars onreproductive axis
Pistils
Fig. 25-7, p. 494
Basal Angiosperms Core Angiosperms
Evolution ofvessel elements
Evolution offlowering plants
(a) One hypothesis of relationships among the flowering plants, based on fossil and molecular evidence. Amborella, water lilies, and star anise are living plantswhose ancestors apparently branched off the angiosperm family tree early. These early groups were followed by the magnoliids, the monocot branch, and the eudicots.
Am
bo
rella
Wat
er li
lies
Sta
r an
ise
Mag
no
liid
s
Mo
no
cots
Eu
dic
ots
Fig. 25-8, p. 495
LEARNING OBJECTIVE 7LEARNING OBJECTIVE 7
• Distinguish between Distinguish between basal basal angiospermsangiosperms and and core angiospermscore angiosperms
KEY TERMSKEY TERMS
• BASAL ANGIOSPERMBASAL ANGIOSPERM • One of three groups of angiosperms thought One of three groups of angiosperms thought
to be ancestral to all other flowering plants to be ancestral to all other flowering plants
• CORE ANGIOSPERMCORE ANGIOSPERM • Group including most angiosperm speciesGroup including most angiosperm species• Divided into three subgroups: Divided into three subgroups: magnoliids, magnoliids,
monocots,monocots, and and eudicotseudicots
KEY TERMSKEY TERMS
• MAGNOLIID MAGNOLIID • One of the groups of flowering plantsOne of the groups of flowering plants• Core angiosperms once classified as “dicots,” Core angiosperms once classified as “dicots,”
but molecular evidence indicates they are but molecular evidence indicates they are neither eudicots nor monocotsneither eudicots nor monocots
• Includes species in magnolia, laurel, and Includes species in magnolia, laurel, and black pepper families, several related familiesblack pepper families, several related families
LEARNING OBJECTIVE 8LEARNING OBJECTIVE 8
• Briefly describe the distinguishing Briefly describe the distinguishing characteristics and give an example or characteristics and give an example or two of each of the following flowering two of each of the following flowering plant families: plant families: magnolia, walnut, magnolia, walnut, cactus, mustard, rose, pea, potato, cactus, mustard, rose, pea, potato, pumpkin, sunflower, grass, orchid,pumpkin, sunflower, grass, orchid, and and agaveagave
Flowering Plant Families 1Flowering Plant Families 1
• More than 300 families More than 300 families
• Magnolia familyMagnolia family• Important ornamentals and source of timberImportant ornamentals and source of timber• Examples:Examples: southern magnolia, tuliptree southern magnolia, tuliptree
Flowering Plant Families 2Flowering Plant Families 2
• Walnut familyWalnut family• Provides nuts for food, wood for furniture Provides nuts for food, wood for furniture • Examples:Examples: English walnut, black walnut, pecan English walnut, black walnut, pecan
• Cactus family Cactus family • Important as ornamentalsImportant as ornamentals• Examples:Examples: prickly pear, Christmas cactus prickly pear, Christmas cactus
(a) The pinnately compound leaves and green fruits of black walnut (Juglans nigra) make the tree easy to recognize.
Young tree
Compound leaf
Catkinof maleflowers Fruit
(a drupe)
Fruit with huskremoved to showhard stone
Femaleflowers
Fig. 25-10a, p. 498
(c) Cactus flowers contain numerous sepals, petals, andstamens. The compound pistil consists of two to many fusedcarpels. In this photo of a prickly pear cactus (Opuntiahumifusa), the petals, stamens, and stigma are evident.
Stamens
Petals
Stigma
Fig. 25-11c, p. 499
Flowering Plant Families 3Flowering Plant Families 3
• Mustard familyMustard family• Many important food cropsMany important food crops• Examples:Examples: cabbage, broccoli, cauliflower, cabbage, broccoli, cauliflower,
turnip, mustardturnip, mustard
• Rose familyRose family• Commercially important fruits and ornamentalsCommercially important fruits and ornamentals• Examples:Examples: apple, pear, plum, cherry, apricot, apple, pear, plum, cherry, apricot,
peach, strawberry, raspberry, rosepeach, strawberry, raspberry, rose
(a) A typical mustard flower, showing thefour petals arranged in the shape of a cross.
Petal
Pistil
Sepal
Stamen
Fig. 25-12a, p. 501
Flowering Plant Families 4Flowering Plant Families 4
• Pea familyPea family• Important food cropsImportant food crops• ExamplesExamples: garden pea, chick pea, green : garden pea, chick pea, green
bean, soybean, lima bean, peanut, red clover, bean, soybean, lima bean, peanut, red clover, alfalfaalfalfa
(a) Part of a common bean (Phaseolus vulgaris)plant, showing flowers and developing fruits.
Remnants of sepals(and sometimes petalsand stamens)
Compound leaf(three leaflets)Young
fruit
Pod (fruit)
Seeds
(c) The bean fruit, a legume, is opened to show the seeds.
Remnants ofstigma and style
(b) Close-up of a bean flower, showingits irregular corolla shape.
Keel (twofused petals)
Wing
Banner
Sepal Corolla
Fig. 25-14a-c, p. 503
Flowering Plant Families 5Flowering Plant Families 5
• Potato familyPotato family• Important food crops and chemicals used as Important food crops and chemicals used as
drugsdrugs• Examples:Examples: potato, tomato, green pepper, potato, tomato, green pepper,
eggplant, petunia, deadly nightshade eggplant, petunia, deadly nightshade (belladonna)(belladonna)
Flowering Plant Families 6Flowering Plant Families 6
• Pumpkin familyPumpkin family• Food cropsFood crops• Examples:Examples: pumpkins, melons, squashes, pumpkins, melons, squashes,
cucumbers, cantaloupe, honeydew, cucumbers, cantaloupe, honeydew, muskmelon, cucumber, watermelon muskmelon, cucumber, watermelon
(a) Cutaway view of a female squash flower. Notethe inferior ovary located beneath the point ofattachment of the sepals and petals.
Ovary
Style
Stigma
Petalsfused intobell shape
Fig. 25-16a, p. 505
Flowering Plant Families 7Flowering Plant Families 7
• Sunflower familySunflower family• One of the largest families of flowering plantsOne of the largest families of flowering plants• Examples:Examples: chrysanthemums, marigolds, chrysanthemums, marigolds,
sunflowers, daisies, and some food plants sunflowers, daisies, and some food plants such as lettuce, globe artichokessuch as lettuce, globe artichokes
(d) Bisexual disc floret.
(c) Female ray floret.
Ovary
Corolla
Anther
Stigmas
Disc floret
Ray floret
Fig. 25-17cd, p. 506
Flowering Plant Families 8Flowering Plant Families 8
• Grass familyGrass family• Most important family of flowering plants from Most important family of flowering plants from
the human standpointthe human standpoint• Examples:Examples: rice, wheat, corn, oats, barley, rye, rice, wheat, corn, oats, barley, rye,
sugarcane, bamboo sugarcane, bamboo
(a) The growth habit of a representative grass plant. Grass flowers, whichare wind pollinated, are highly modified. Note, for example, the long,feathery stigmas, adapted to efficiently catch wind-borne pollen.
Fibrous rootsystem
StolonRhizome
Sheath
Blade
Inflorescence
Lemma
Reduced petals
Ovary
Featherystigma
Filament
Palea
Anther
Fig. 25-18a, p. 507
Flowering Plant Families 9Flowering Plant Families 9
• Orchid familyOrchid family• One of the largest families of flowering plants; One of the largest families of flowering plants;
contains a greater variety of flowers than any contains a greater variety of flowers than any other familyother family
• Example:Example: the vanilla orchid the vanilla orchid
• Agave familyAgave family• Best known for ornamentalsBest known for ornamentals• Examples:Examples: century plant, sisal hemp, century plant, sisal hemp,
bowstring hempbowstring hemp
(a) The moth orchid (Phalaenopsis hybrid)has photosynthetic aerial roots.
Aerial roots
Fig. 25-19a, p. 509
(b) A Cymbidium hybrid has pseudobulbsthat function as storage organs.
Pseudobulbs
Fig. 25-19b, p. 509
(c) Orchid flowers, such as Dendrobium, aredistinctive in that the third petal forms a lip.
Lip (modifiedpetal)
Sepal
Petal
Fig. 25-19c, p. 509