ap bio lecture ch24 evolution and diversity of life
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Evolution and Diversity of
Plants
Chapter 24
Evolution and Evolution and Diversity of Diversity of
PlantsPlants2
OutlineOutline
Evolutionary History Evolutionary History
Alternation of GenerationsAlternation of Generations
Nonvascular PlantsNonvascular Plants
Vascular PlantsVascular Plants
SeedlessSeedless
SeedSeed
AngiospermsAngiosperms
Monocots and EudicotsMonocots and Eudicots
FlowersFlowers
Evolution and Evolution and Diversity of Diversity of
PlantsPlants3
Evolutionary History of PlantsEvolutionary History of PlantsMore than 98% of all biomass is plantsMore than 98% of all biomass is plants
Multicellular photosynthetic eukaryotesMulticellular photosynthetic eukaryotes
280,000 known species280,000 known species
Thought to have evolved from freshwater Thought to have evolved from freshwater algae over 500 myaalgae over 500 mya
Evolution of plants marked by four Evolution of plants marked by four evolutionary events associated with four evolutionary events associated with four major groups of plantsmajor groups of plants
Nonvascular PlantsNonvascular Plants
Advent of nourishment of a multicellular embryo Advent of nourishment of a multicellular embryo within the body of the female plantwithin the body of the female plant
4Representatives of the
Four Major Groups of Plants
Evolution and Evolution and Diversity of Diversity of
PlantsPlants5
Evolutionary History of PlantsEvolutionary History of Plants
Seedless vascular plants Seedless vascular plants
Advent of vascular tissueAdvent of vascular tissue
Gymnosperms and angiospermsGymnosperms and angiosperms
Produce seedsProduce seeds
Flowering PlantsFlowering Plants
Attract pollinators that give rise to Attract pollinators that give rise to fruitsfruits
6 Evolutionary History of Plants
Evolution and Evolution and Diversity of Diversity of
PlantsPlants7
Alternation of GenerationsAlternation of GenerationsLife cycle involves alternation of generationsLife cycle involves alternation of generations
Multicellular 1n individuals (gametophytes) Multicellular 1n individuals (gametophytes) produce multicellular 2n individuals (sporophytes)produce multicellular 2n individuals (sporophytes)
Multicellular 2n individuals (sporophytes) produce Multicellular 2n individuals (sporophytes) produce multicellular 1n individuals (gametophytes)multicellular 1n individuals (gametophytes)
Sporophyte (2n):Sporophyte (2n): Multicellular individual that produces spores by Multicellular individual that produces spores by meiosismeiosis
Spore is haploid cell that will become the Spore is haploid cell that will become the gametophytegametophyte
Gametophyte (1n):Gametophyte (1n): Multicellular individual that produces gametesMulticellular individual that produces gametes Gametes fuse in fertilization to form zygoteGametes fuse in fertilization to form zygote Zygote is a diploid cell that will become the Zygote is a diploid cell that will become the sporophytesporophyte
8 Alternation of Generations
Evolution and Evolution and Diversity of Diversity of
PlantsPlants9
Alternation of GenerationsAlternation of Generations
Appearance of generations varies widelyAppearance of generations varies widely
In ferns, female portions are archegonia In ferns, female portions are archegonia and are fertilized by flagellated spermand are fertilized by flagellated sperm
In angiosperm, female gametophyte In angiosperm, female gametophyte (embryo sac), consists of an ovule(embryo sac), consists of an ovule
Following fertilization, ovule becomes Following fertilization, ovule becomes seedseed
In seed plants, pollen grains are mature In seed plants, pollen grains are mature sperm-bearing male gametophytessperm-bearing male gametophytes
10 Reduction in the Size of the Gametophyte
Evolution and Evolution and Diversity of Diversity of
PlantsPlants11
Other Terrestrial AdaptationsOther Terrestrial Adaptations
Vascular tissue transports water and Vascular tissue transports water and nutrients to the body of the plantnutrients to the body of the plant
Cuticle provides an effective barrier to Cuticle provides an effective barrier to water losswater loss
Stomata bordered by guard cells that Stomata bordered by guard cells that regulate opening, and thus water regulate opening, and thus water lossloss
12 Protection of Eggs and Embryos
13 Leaves of Vascular Plants
Evolution and Evolution and Diversity of Diversity of
PlantsPlants14
Nonvascular PlantsNonvascular Plants
Nonvascular plants (bryophytes) Nonvascular plants (bryophytes)
Lack specialized means of transporting Lack specialized means of transporting water and organic nutrientswater and organic nutrients
Do not have true roots, stems, and Do not have true roots, stems, and leavesleaves
Gametophyte is dominant generationGametophyte is dominant generation
Produces eggs in archegoniaProduces eggs in archegonia
Produces flagellated sperm in antheridiaProduces flagellated sperm in antheridia
Sperm swim to egg in film of water to Sperm swim to egg in film of water to make zygotemake zygote
Evolution and Evolution and Diversity of Diversity of
PlantsPlants15
Nonvascular PlantsNonvascular PlantsHornworts (phlym Anthocerophyta) have Hornworts (phlym Anthocerophyta) have small sporophytes that carry on small sporophytes that carry on photosynthesisphotosynthesis
Liverworts (phylum Hepatophyta) have Liverworts (phylum Hepatophyta) have either flattened thallus or leafy either flattened thallus or leafy appearanceappearance
Mosses (phylum Bryophyta) usually have Mosses (phylum Bryophyta) usually have a leafy shoot, although some are a leafy shoot, although some are secondarily flattenedsecondarily flattened
Can reproduce asexually by fragmentationCan reproduce asexually by fragmentation
Dependent sporophyte consists of foot, Dependent sporophyte consists of foot, stalk, and sporangiumstalk, and sporangium
16Hornwort
17Liverwort, Marchantia
18Moss (Polytrichum) Life Cycle
Evolution and Evolution and Diversity of Diversity of
PlantsPlants19
Vascular PlantsVascular Plants
Xylem conducts water and dissolved Xylem conducts water and dissolved minerals up from rootsminerals up from roots
Phloem conducts sucrose and other Phloem conducts sucrose and other organic compounds throughout the plantorganic compounds throughout the plant
Lignin strengthens walls of conducting Lignin strengthens walls of conducting cells in xylemcells in xylem
Most seedless vascular plants are Most seedless vascular plants are homosporoushomosporousWindblown spores are dispersal agentsWindblown spores are dispersal agents
All seed plants are heterosporous and All seed plants are heterosporous and have male and female gametophyteshave male and female gametophytesSeeds disperse offspringSeeds disperse offspring
20Cooksonian Fossil
21Vascular Tissue
Evolution and Evolution and Diversity of Diversity of
PlantsPlants22
Seedless Vascular PlantsSeedless Vascular Plants
Club Mosses (phylum Lycophyta)Club Mosses (phylum Lycophyta)
Typically, branching rhizome sends up Typically, branching rhizome sends up short aerial stemsshort aerial stems
Leaves are microphylls (have only one Leaves are microphylls (have only one strand of vascular tissue)strand of vascular tissue)
Sporangia occur on surfaces of Sporangia occur on surfaces of sporophyllssporophylls
Grouped into club-shaped strobiliGrouped into club-shaped strobili
23 Club Moss, Lycopodium
Evolution and Evolution and Diversity of Diversity of
PlantsPlants24
Seedless Vascular PlantsSeedless Vascular Plants
Ferns and AlliesFerns and Allies
Horsetails (phylum Sphenophyta) Horsetails (phylum Sphenophyta)
Rhizome produces tall aerial stemsRhizome produces tall aerial stems
Contains whorls of slender, green Contains whorls of slender, green branchesbranches
Small, scalelike leaves also form whorls Small, scalelike leaves also form whorls at the jointsat the joints
25 Horsetail, Equisetum
Evolution and Evolution and Diversity of Diversity of
PlantsPlants26
FernsFerns
Whisk Ferns (phylum Psilotophyta)Whisk Ferns (phylum Psilotophyta)Branched rhizome has rhizoidsBranched rhizome has rhizoids
Mutualistic mycorrhizal fungus helps Mutualistic mycorrhizal fungus helps gather nutrientsgather nutrients
Ferns (phylum Pterophyta)Ferns (phylum Pterophyta)Large conspicuous frondsLarge conspicuous fronds
Divided into leafletsDivided into leaflets
Dominant sporophyte produces Dominant sporophyte produces windblown sporeswindblown spores
27 Whisk fern, Psilotum
28Diversity of ferns
29Fern Life Cycle
Evolution and Evolution and Diversity of Diversity of
PlantsPlants30
Seed PlantsSeed Plants
Seed plants are the most plentiful Seed plants are the most plentiful plants in the biosphereplants in the biosphere
Seed coat and stored food allow an Seed coat and stored food allow an embryo to survive harsh conditions embryo to survive harsh conditions during long period of dormancyduring long period of dormancy
HeterosporousHeterosporous
Drought-resistant pollen grainsDrought-resistant pollen grains
Ovule develops into seedOvule develops into seed
31Seed Plants
Evolution and Evolution and Diversity of Diversity of
PlantsPlants32
GymnospermsGymnosperms
Gymnosperms have ovules and seeds Gymnosperms have ovules and seeds exposed on the surface of exposed on the surface of sporophyllssporophylls
ConfiersConfiers
CycadsCycads
GinkgoesGinkgoes
GnetophytesGnetophytes
Evolution and Evolution and Diversity of Diversity of
PlantsPlants33
ConifersConifers
Conifers, as well as other gymnosperm Conifers, as well as other gymnosperm phyla, bear conesphyla, bear cones
Tough, needlelike leaves of pines Tough, needlelike leaves of pines conserve water with a thick cuticle conserve water with a thick cuticle and recessed stomataand recessed stomata
Considered a “soft” wood because it Considered a “soft” wood because it consists primarily of xylem tissueconsists primarily of xylem tissue
34Pine Life Cycle
Evolution and Evolution and Diversity of Diversity of
PlantsPlants35
CycadsCycads
Cycads (phylum Cycadophyta) Cycads (phylum Cycadophyta)
Large, finely divided leaves that grow Large, finely divided leaves that grow in clusters at the top of the stemin clusters at the top of the stem
Pollen and seed cones on separate Pollen and seed cones on separate plantsplants
Pollinated by insectsPollinated by insects
36Cycad Cones
Figure24.19
Evolution and Evolution and Diversity of Diversity of
PlantsPlants37
GinkgoesGinkgoes
Ginkgoes (phylum Ginkgophyta) Ginkgoes (phylum Ginkgophyta)
DioeciousDioecious
Some trees producing seedsSome trees producing seeds
Others producing pollenOthers producing pollen
One surviving species (One surviving species (Gingko bilobaGingko biloba))
38The Ginkgo Tree
39Ephedra
Figure24.21
40Welwitschia miribilis
Evolution and Evolution and Diversity of Diversity of
PlantsPlants41
GnetophytesGnetophytes
Gnetophytes (phylum Gnetophyta)Gnetophytes (phylum Gnetophyta)
Have similarly structured xylemHave similarly structured xylem
None have archegoniaNone have archegonia
Strobili have similar constructionStrobili have similar construction
Evolution and Evolution and Diversity of Diversity of
PlantsPlants42
AngiospermsAngiosperms
Angiosperms (phylum Anthophyta) Angiosperms (phylum Anthophyta)
An exceptionally large and successful An exceptionally large and successful group of plantsgroup of plants
Ovules are always enclosed within Ovules are always enclosed within diploid tissuesdiploid tissues
Became dominant group of plants in Became dominant group of plants in the late Cretaceous and early the late Cretaceous and early Paleocene periodsPaleocene periods
43Amborella trichopoda
Evolution and Evolution and Diversity of Diversity of
PlantsPlants44
Monocots and EudicotsMonocots and Eudicots
Two classes of flowering plantsTwo classes of flowering plants
Monocotyledones (Monocots)Monocotyledones (Monocots)
One cotyledon in seedOne cotyledon in seed
Eudicotyledones (Dicots)Eudicotyledones (Dicots)
Two cotyledons in seedTwo cotyledons in seed
45Flower Diversity
Evolution and Evolution and Diversity of Diversity of
PlantsPlants46
The FlowerThe Flower
Peduncle (flower stalk) expands at tip Peduncle (flower stalk) expands at tip into a receptacleinto a receptacle
Bears sepals, petals, stamens, and Bears sepals, petals, stamens, and carpels, all attached to receptacle in carpels, all attached to receptacle in whorlswhorls
Calyx (collection of sepals) protect Calyx (collection of sepals) protect flower bud before it opensflower bud before it opens
Corolla (collection of petals)Corolla (collection of petals)
Evolution and Evolution and Diversity of Diversity of
PlantsPlants47
The FlowerThe Flower
Each stamen consists of an anther and Each stamen consists of an anther and a filament (stalk)a filament (stalk)
Carpel has three major regionsCarpel has three major regions
Ovary - Swollen baseOvary - Swollen base
FruitFruit
Style - Elevates stigmaStyle - Elevates stigma
Stigma - Sticky receptor of pollen Stigma - Sticky receptor of pollen grainsgrains
48Generalized Flower
49Flowering plant life cycle
Evolution and Evolution and Diversity of Diversity of
PlantsPlants50
Flowers and DiversificationFlowers and DiversificationWind-pollinated flowers are usually not Wind-pollinated flowers are usually not showyshowy
Bird-pollinated flowers are often colorfulBird-pollinated flowers are often colorful
Night-blooming flowers attract nocturnal Night-blooming flowers attract nocturnal mammals or insectsmammals or insects
Usually white or cream-coloredUsually white or cream-colored
Fruits of flowers protect and aid in Fruits of flowers protect and aid in dispersaldispersal
Utilize wind, gravity, water, and animals Utilize wind, gravity, water, and animals for dispersalfor dispersal
Evolution and Evolution and Diversity of Diversity of
PlantsPlants51
ReviewReview
Evolutionary History Evolutionary History
Alternation of GenerationsAlternation of Generations
Nonvascular PlantsNonvascular Plants
Vascular PlantsVascular Plants
SeedlessSeedless
SeedSeed
AngiospermsAngiosperms
Monocots and EudicotsMonocots and Eudicots
FlowersFlowers
Evolution and Diversity of
Plants
Ending Slide Chapter 24