plant apbio
TRANSCRIPT
Chapter 21Chapter 21
TheThePlant KingdomPlant Kingdom
Chapter 21 2 Key Features of PlantsKey Features of Plants
Multicellularity Multicellularity Ability to photosynthesize (most)Ability to photosynthesize (most)Exhibit Exhibit alternation of generationsalternation of generations (a (a multicellular diploid generation multicellular diploid generation alternates with a multicellular haploid alternates with a multicellular haploid generation)generation)
Chapter 21 3 Alternation of GenerationsAlternation of Generations
Diploid Diploid sporophytesporophyte plant produces plant produces haploid spores through meiosishaploid spores through meiosis
Spores divide by mitosis and develop Spores divide by mitosis and develop into haploid gametophyte plantsinto haploid gametophyte plants
Haploid Haploid gametophyte gametophyte plant produces plant produces haploid gametes through mitosishaploid gametes through mitosis
Gametes fuse to form diploid Gametes fuse to form diploid zygoteszygotes, , which divide by mitosis and develop which divide by mitosis and develop into diploid sporophytesinto diploid sporophytes
Chapter 21 4
HaploidHaploidDiploidDiploid
GametophytesGametophytesform by meiosisform by meiosis
Spores formSpores formby meiosisby meiosis
nnnnnn
Alternation of GenerationsAlternation of Generationsin Plantsin Plants
SporeSporeMotherMother
CellCell
EggEgg
SpermSpermGametes meetGametes meet& fuse to form& fuse to formzygotezygote
ZygoteZygote
EmbryoEmbryoSporo-Sporo-phytephyte
22nn
SporesSporesnn
Gameto-Gameto-phytephyte
22nn
nnnn
22nn
22nn
22nn
Chapter 21 5
Evolution of PlantsEvolution of Plants
The evolutionary origin of plantsThe evolutionary origin of plants• Division Rhodophyta—red algaeDivision Rhodophyta—red algae
• Division Phaeophyta—brown algaeDivision Phaeophyta—brown algae
• Division Chlorophyta—green algae and the Division Chlorophyta—green algae and the origin of land plantsorigin of land plants
Chapter 21 6 Green AlgaeGreen Algae
Several lines of evidence support the Several lines of evidence support the hypothesis that green algae gave rise to hypothesis that green algae gave rise to plantsplants
DNA comparisons show that green algae DNA comparisons show that green algae are plants’ closest living relativesare plants’ closest living relatives
Both use the same type of chlorophyll and Both use the same type of chlorophyll and accessory pigments in photosynthesisaccessory pigments in photosynthesis
Both store food as starchBoth store food as starchBoth have cell walls made of celluloseBoth have cell walls made of cellulose
Chapter 21 7 Fresh Water AncestorsFresh Water Ancestors
Most green algae live in fresh water, Most green algae live in fresh water, suggesting that early plants evolved in suggesting that early plants evolved in freshwater habitatsfreshwater habitats
Early green algae must have evolved Early green algae must have evolved characteristics to withstand the challenges characteristics to withstand the challenges of fresh water habitats, e.g. temperature of fresh water habitats, e.g. temperature extremes, periods of drynessextremes, periods of dryness
These adaptations provided a foundation for These adaptations provided a foundation for descendants to evolve traits for life on landdescendants to evolve traits for life on land
Chapter 21 8
The Evolution of Land PlantsThe Evolution of Land PlantsRoots and rootlike structures (anchor & absorb)Roots and rootlike structures (anchor & absorb)Vascular tissue for transport of water & nutrientsVascular tissue for transport of water & nutrientsStiffening substance (lignin) for supportStiffening substance (lignin) for supportWaxy covering (cuticle) limits evaporationWaxy covering (cuticle) limits evaporationStomatal poresStomatal pores• Mediate gas exchangeMediate gas exchange• Regulate water vapor lossRegulate water vapor loss
Evolutionary adaptations in plant reproductionEvolutionary adaptations in plant reproduction• Early algae relied on water currents for fertilizationEarly algae relied on water currents for fertilization• Dry land adaptation include the generation of Dry land adaptation include the generation of
pollen, seeds, flowers, and fruit…pollen, seeds, flowers, and fruit…• Adaptations in the alternation of generations…Adaptations in the alternation of generations…
Chapter 21 9 Reproduction Without WaterReproduction Without Water
PollenPollen• A reduced male gametophyte that allows wind A reduced male gametophyte that allows wind
(instead of water) to carry sperm to eggs(instead of water) to carry sperm to eggs
SeedsSeeds• Nourish, protect, and help disperse developing Nourish, protect, and help disperse developing
embryosembryos
FlowersFlowers• Attract pollinators Attract pollinators
FruitsFruits• Attract animals to disperse seedsAttract animals to disperse seeds
Chapter 21 10 Major Groups of PlantsMajor Groups of Plants
BryophytesBryophytes ( (nonvascular plantsnonvascular plants))• Lack well-developed structures for Lack well-developed structures for
conducting water and nutrientsconducting water and nutrients
Tracheophytes Tracheophytes ((Vascular plantsVascular plants ) )• Have a complex vascular systemHave a complex vascular system
Chapter 21 11
Evolutionary Evolutionary TreeTreeof Major of Major Plant Plant GroupsGroups
AncestralAncestralAlgaeAlgae
AncestralAncestralAlgaeAlgae
Liver-Liver-wortsworts MossesMosses
BryophytesBryophytes
True vascular tissueTrue vascular tissue& lignin appear& lignin appear
FernsFerns Gymno-Gymno-spermssperms
Seeds andSeeds andpollen appearpollen appear
Flowers &Flowers &Fruits appearFruits appear
Seed PlantsSeed Plants
Angio-Angio-spermssperms
TracheophytesTracheophytes
Chapter 21 12
The BryophytesThe Bryophytes
Nonvascular plantsNonvascular plants
No true roots, leaves, and stemsNo true roots, leaves, and stems
Still require a moist environmentStill require a moist environment
Anchoring rhizoids absorb water & nutrientsAnchoring rhizoids absorb water & nutrients
Reproductive structures protect gametesReproductive structures protect gametes
Still depend on water for fertilizationStill depend on water for fertilization
Dominant gametophyte generationDominant gametophyte generation
Chapter 21 13
Liverworts & MossesLiverworts & MossesLiverwortsLiverwortsFemaleFemale
GametophyteGametophyteArchegoniumArchegonium
(a)(a)(a)(a) (b)(b)(b)(b)
MossesMosses
FemaleFemaleGametophytesGametophytes
SporophytesSporophytes
Chapter 21 14 The Bryophytes: ReproductionThe Bryophytes: Reproduction
Gametes develop within protected Gametes develop within protected structures on gametophytestructures on gametophyte• ArchegoniaArchegonia (singular, archegonium) (singular, archegonium)
produce eggsproduce eggs• AntheridiaAntheridia (singular, antheridium) (singular, antheridium)
produce spermproduce sperm• Archegonia and antheridia may be Archegonia and antheridia may be
located on the same plant or on different located on the same plant or on different plantsplants
Chapter 21 15
Life Life Cycle Cycle
of a of a Moss Moss
(a)(a)
Zygote develops intoZygote develops intosporophyte withinsporophyte withingametophytegametophyte
SporophyteSporophyteCapsule Capsule
Fertilization Fertilization
Mei
osis
M
eios
is
Haploid spores liberatedHaploid spores liberatedfrom sporophyte capsulefrom sporophyte capsule
OldOldGametophyteGametophyte
Spores disperseSpores disperseand germinateand germinate
HaploidHaploid11nn
DiploidDiploid22nn
Chapter 21 16
Life Life Cycle Cycle
of a of a Moss Moss
(b)(b)HaploidHaploid
11nn
DiploidDiploid22nn
Spore germinatesSpore germinatesinto gametophyteinto gametophyte
LeafyLeafyGametophyteGametophyte
ArchegoniumArchegoniumproduces eggproduces egg
AntheridiumAntheridiumproduces spermproduces sperm
Sperm swimSperm swimto eggto egg
FertilizationFertilization
Chapter 21 17 The Vascular PlantsThe Vascular Plants
Have roots, stems, and leavesHave roots, stems, and leavesHave Have vesselsvessels impregnated with the impregnated with the stiffening agent ligninstiffening agent lignin
Sporophyte generation is dominantSporophyte generation is dominantInclude the seedless vascular plants Include the seedless vascular plants and the seed plantsand the seed plants
Chapter 21 18
Division Tracheophyta:Division Tracheophyta:Vascular PlantsVascular Plants
Adapted to life in drier conditionsAdapted to life in drier conditions• Had to generate body supportHad to generate body support
• Vessels to conduct water and nutrientsVessels to conduct water and nutrients
• A stiffening substance called ligninA stiffening substance called lignin
Seedless plants: club mosses, horsetails, Seedless plants: club mosses, horsetails, and fernsand ferns• Sporophyte generation more dominantSporophyte generation more dominant
• Fertilization still relies on waterFertilization still relies on water
Chapter 21 19
Life Cycle Life Cycle of Ferns (a)of Ferns (a)
HaploidHaploid11nn
DiploidDiploid22nn
GametophyteGametophyte
Sporophyte developsSporophyte developsfrom gametophytefrom gametophyte
RootRoot
StemStem
SporophyteSporophyte
Masses ofMasses ofSporangiaSporangia
MeiosisMeiosis
Haploid spores liberatedHaploid spores liberatedfrom sporangiumfrom sporangium
SporangiumSporangium
Chapter 21 20
Life Cycle of Ferns (b)Life Cycle of Ferns (b)
HaploidHaploid11nn
DiploidDiploid22nn
Haploid spores liberatedHaploid spores liberatedfrom sporangiumfrom sporangium
Spores disperseSpores disperse& germinate& germinate
GametophyteGametophyte
ArchegoniumArchegoniumproduces eggproduces egg
AntheridiumAntheridiumproduces spermproduces sperm
Sperm swimSperm swimto eggto egg
FertilizationFertilization
Chapter 21 21
Seedless PlantsSeedless Plants
Club MossesClub MossesClub MossesClub Mosses
HorsetailsHorsetailsHorsetailsHorsetails
FernsFernsFernsFerns
Chapter 21 22
Seed Plants:Seed Plants:GeneralGeneral
Dominance of the sporophyte generationDominance of the sporophyte generation
Reproductive adaptationsReproductive adaptations• Pollen Pollen
– Wind and pollinators for fertilizationWind and pollinators for fertilization– Water not required for fertilizationWater not required for fertilization
• SeedsSeeds– Stores food for embryoStores food for embryo– Embryo protection for unfavorable environmentsEmbryo protection for unfavorable environments
Chapter 21 23
SeedsSeeds
(a) Gymnosperm(a) Gymnosperm (d) Water Dispersal(d) Water Dispersal
(c) Wind Dispersal(c) Wind Dispersal
Stored FoodStored FoodStored FoodStored Food
EmbryoEmbryoEmbryoEmbryo
Seed CoatSeed CoatSeed CoatSeed Coat (b) Angiosperm(b) Angiosperm
Chapter 21 24
Seed Plants:Seed Plants:GymnospermsGymnosperms
Nonflowering seed plantsNonflowering seed plantsProduce "naked seeds"Produce "naked seeds"Three divisions:Three divisions:• ConiferophytaConiferophyta• CycadophytaCycadophyta• GinkgophytaGinkgophyta
Conifers are adapted to dry, cold conditionsConifers are adapted to dry, cold conditions• Thin, waterproof needles to decrease evaporationThin, waterproof needles to decrease evaporation• Evergreen; year-round photosynthesisEvergreen; year-round photosynthesis• Produce an "antifreeze" substance in sapProduce an "antifreeze" substance in sap
Chapter 21 25
Two UncommonTwo UncommonGymnospermsGymnosperms
(a) Gingko(a) Gingko
(b) A Cycad – either (b) A Cycad – either male or femalemale or female
Chapter 21 26 Gymnosperms: ConifersGymnosperms: Conifers
Adapted to dry, cold conditions:Adapted to dry, cold conditions:• Retain green leaves throughout the year Retain green leaves throughout the year
(evergreen)(evergreen)• Thin, needle-like leaves covered with Thin, needle-like leaves covered with
waterproofing material to reduce waterproofing material to reduce evaporationevaporation• Produce an Produce an ““antifreeze” in sapantifreeze” in sap
Chapter 21 27
Life Life Cycle of Cycle of the Pine the Pine (a) (a)
HaploidHaploid11nn
DiploidDiploid22nn
MatureMatureSporophyteSporophyte
MatureMatureSporophyteSporophyte
SeedlingsSeedlings(Sporophyte)(Sporophyte)SeedlingsSeedlings
(Sporophyte)(Sporophyte)
MaleMaleConeConeMaleMale
ConeCone
MaleMaleScaleScale
MaleMaleScaleScale
MEIOSISMEIOSIS
MEIOSISMEIOSIS
Male gametophytesMale gametophytes(pollen) liberated(pollen) liberated
FemaleFemaleConeCone
FemaleFemaleConeCone
FemaleFemaleScaleScale
FemaleFemaleScaleScale
OvuleOvuleOvuleOvule
Spore-formingSpore-formingCellCell
Spore-formingSpore-formingCellCell
MEIOSISMEIOSIS
MEIOSISMEIOSIS
Chapter 21 28
Life Cycle of the Pine (b)Life Cycle of the Pine (b)
HaploidHaploid11nn
DiploidDiploid22nn
MEIOSISMEIOSIS
MEIOSISMEIOSIS
Pollen liberated;Pollen liberated;Dispersed by windDispersed by wind
MEIOSISMEIOSIS
MEIOSISMEIOSIS
SeedlingsSeedlings(Sporophyte)(Sporophyte)SeedlingsSeedlings
(Sporophyte)(Sporophyte)
Egg CellEgg CellEgg CellEgg Cell
FemaleFemaleGametophyteGametophyte
FemaleFemaleGametophyteGametophyte
Pollen lands onPollen lands onfemale scalefemale scale
PollenPollenTubeTube
PollenPollenTubeTube
FERTILIZATIONFERTILIZATIONFERTILIZATIONFERTILIZATION
SeedSeedSeedSeed
EmbryoEmbryoEmbryoEmbryo
Chapter 21 29
Seed Plants:Seed Plants:AngiospermsAngiosperms
Flowering seed plantsFlowering seed plantsThe dominant plant form on EarthThe dominant plant form on EarthMajor evolutionary adaptationsMajor evolutionary adaptations• Flowers to attract pollinatorsFlowers to attract pollinators• Fruit to protect seeds and developing Fruit to protect seeds and developing
embryoembryo• Broad leavesBroad leaves
– Increase photosynthesis during the growing Increase photosynthesis during the growing seasonseason
– Shed during periods of cold and droughtShed during periods of cold and drought
Chapter 21 30
Monocot vs DicotMonocot vs Dicot
Class Monocotyledoneae (monocots): Class Monocotyledoneae (monocots): grasses, grains, corngrasses, grains, corn
1 cotyledon1 cotyledonleave veins in parallel linesleave veins in parallel linesFlower parts, in multiple of 3Flower parts, in multiple of 3scattered vascular bundlesscattered vascular bundles
Class Dicotyledoneae (dicots): hardwood Class Dicotyledoneae (dicots): hardwood trees, shrubs, and herbstrees, shrubs, and herbs
2 cotyledons, web-like veins, flower 2 cotyledons, web-like veins, flower petals in 4/5s, ringed vascular bundlespetals in 4/5s, ringed vascular bundles
Chapter 21 31
Chapter 21 32 FlowersFlowers
FlowersFlowers are reproductive structures in which are reproductive structures in which both male and female gametophytes are both male and female gametophytes are formedformed
Believed to have evolved when gymnosperm Believed to have evolved when gymnosperm ancestors formed an association with animalsancestors formed an association with animals• Animals benefited by eating some of the protein-Animals benefited by eating some of the protein-
rich pollenrich pollen• Plants benefited by using animals as pollinatorsPlants benefited by using animals as pollinators
Most flowers are showy and attract animal Most flowers are showy and attract animal pollinators (e.g. insects)pollinators (e.g. insects)
Chapter 21 33
Life Cycle of aLife Cycle of aFlowering Plant (a)Flowering Plant (a)
FruitFruitFruitFruit
SeedSeedSeedSeed
FoodFoodFoodFoodEmbryoEmbryoEmbryoEmbryo
Seed CoatSeed CoatSeed CoatSeed Coat
SeedlingSeedlingSeedlingSeedling FlowerFlowerFlowerFlowerAntherAntherAntherAnther
MEIOSISMEIOSISMEIOSISMEIOSIS
OvaryOvaryOvaryOvary
OvuleOvuleOvuleOvule
Spore-formingSpore-formingCellCell
Spore-formingSpore-formingCellCell
HaploidHaploid11nn
DiploidDiploid22nn
Chapter 21 34
Life Cycle of a Flowering Plant (b)Life Cycle of a Flowering Plant (b)
FruitFruitFruitFruit
MEIOSISMEIOSISMEIOSISMEIOSIS
MEIOSISMEIOSIS
MEIOSISMEIOSIS
SporeSporeSporeSpore
FemaleFemaleGametophyteGametophyte
FemaleFemaleGametophyteGametophyte
Egg CellEgg CellEgg CellEgg Cell
Pollen (malePollen (malegametophyte)gametophyte)Pollen (malePollen (male
gametophyte)gametophyte)
StigmaStigmaStigmaStigma
PollenPollenTubeTube
PollenPollenTubeTube
SpermSpermNucleiNuclei
SpermSpermNucleiNuclei
FERTILIZATION
FERTILIZATION
FERTILIZATION
FERTILIZATION
HaploidHaploid11nn
DiploidDiploid22nn
Chapter 21 35 Fruits Encourage Seed DispersalFruits Encourage Seed Dispersal
FruitsFruits are mature ovaries that contain are mature ovaries that contain developing seedsdeveloping seeds
Various fruit adaptations help disperse Various fruit adaptations help disperse seedsseeds• Edible fruits entice animals to eat them Edible fruits entice animals to eat them
(seeds pass through digestive tract (seeds pass through digestive tract unharmed)unharmed)• Burrs cling to animal furBurrs cling to animal fur•Winged fruits are carried through the airWinged fruits are carried through the air
Chapter 21 36 Broad LeavesBroad Leaves
Broad leaves of angiosperms collect more Broad leaves of angiosperms collect more sunlight for photosynthesis than narrow sunlight for photosynthesis than narrow leaves of gymnospermsleaves of gymnosperms
Temperate angiosperms drop leaves to Temperate angiosperms drop leaves to conserve water when it is in short supply conserve water when it is in short supply (fall, winter)(fall, winter)
Tropical and subtropical angiosperms are Tropical and subtropical angiosperms are evergreenevergreen•May shed leaves during dry seasonMay shed leaves during dry season
Chapter 21 37 Broad LeavesBroad Leaves
Photosynthetic advantage is offset by Photosynthetic advantage is offset by fact that broad, tender leaves are more fact that broad, tender leaves are more appealing to herbivores than tough, appealing to herbivores than tough, waxy needles of coniferswaxy needles of conifers
Angiosperm defenses includeAngiosperm defenses include• Physical defenses (thorns, spines, resins)Physical defenses (thorns, spines, resins)• Chemical defenses (make plant tissue Chemical defenses (make plant tissue
poisonous or distasteful)poisonous or distasteful)
Chapter 21 38 Crucial Ecological RoleCrucial Ecological Role
Through photosynthesis, plants provide Through photosynthesis, plants provide food, directly or indirectly, for all of the food, directly or indirectly, for all of the animals, fungi, and non-photosynthetic animals, fungi, and non-photosynthetic microbes on landmicrobes on land
Plants produce oxygen gas as a Plants produce oxygen gas as a byproduct of photosynthesis, byproduct of photosynthesis, continually replenishing oxygen in the continually replenishing oxygen in the atmosphere atmosphere
Chapter 21 39 Crucial Ecological RoleCrucial Ecological Role
Plants help create and maintain soilPlants help create and maintain soil• Dead plant material is decomposed by Dead plant material is decomposed by
fungi, prokaryotes, and other fungi, prokaryotes, and other decomposersdecomposers• Decomposed plant tissue becomes part Decomposed plant tissue becomes part
of the soil, making it more fertileof the soil, making it more fertile• Roots of living plants help hold soil Roots of living plants help hold soil
together, preventing erosion by wind and together, preventing erosion by wind and water water
Chapter 21 40 Human Necessities and LuxuriesHuman Necessities and Luxuries
Plants provide shelterPlants provide shelter•Wood is used to construct housing Wood is used to construct housing
Plants provide fuelPlants provide fuel•Wood: important fuel for warming and Wood: important fuel for warming and
cooking in many parts of the worldcooking in many parts of the world• Coal: derived from the remains of Coal: derived from the remains of
ancient plants that have been ancient plants that have been transformed by geological processestransformed by geological processes
Chapter 21 41 Human Necessities and LuxuriesHuman Necessities and Luxuries
Plants provide medicinePlants provide medicine•Many medicines and drugs were Many medicines and drugs were
originally found in and extracted from originally found in and extracted from plants, e.g. aspirin, Taxol, morphineplants, e.g. aspirin, Taxol, morphine
Plants provide pleasurePlants provide pleasure• Flowers, gardens, and lawnsFlowers, gardens, and lawns• Coffee, tea, and wineCoffee, tea, and wine
Chapter 21Chapter 21
The EndThe End