the plant kingdom. key characteristics of plants multicellular cell specialization photosynthetic...
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The Plant Kingdom
Key Characteristics of PlantsMulticellularCell specializationPhotosynthetic autotrophsSessileAlternation of GenerationsSporophytegametophyte
Green algae gave rise to plantsBoth use the same type of chlorophyll and assessory pigmentsDNA analysis shows commonalityBoth store food as starch and have cell walls made of cellulose.
Evolutionary Relationship Between Plants and Green Algae
Adaptation to Land
Lost supportive buoyancy of waterNo longer surrounded by water and nutrients.Variation in climateRoots or rootlike structuresCuticleStomataEventually..Vascular tissuelignin
Requirements for Plants to Survive on Land
Without water, strategies for dipersal of sex cells needed to be developed
Sex cells and zygote needed a means of dispersal that was independent of water.Protective structures were required to protect the developing embryos.The above were achieved with the origin of the seed plants.
CharacteristicsNonvascularLack true roots, leaves and stemsRootlike structure s are called rhizoidsRely on diffusion and poorly developed conducting tissues to distribute water and nutrients.Enclosed reproductive structuresArchegoniaAntheridia
Characteristics of Nonvascular Plants
Reproductive cycle for Bryophytes
Types of Nonvascular Plants
Vascular Plants(tracheophytes)Conducting vessels also provide support.XylemPhloem
Seedless Vascular Plants(reproduce via spores)
Types of Seedless Vascular Plants
PSILOPHTAwhisk fernsEpiphytesRootless and leafless
LYCOPHYTAclub mossesProduces a sporangia bearing strobilus.
SPHENOPHYTAHorsetailsGenus: EquisetumLarge deposits of silica in their leaves.Jointed stems with whorled leaf arrangement.
PTEROPHYTATrue fernsBroad leaves called frondsLeaflets called pinnaeSporangium (sorus pl sori) are formed on the underside of the fronds.Unfolding fronds are called fiddleheads.Spores are dispersed by the wind.
Fern reproductive life cycle
Seed producing plantsMajor adaptationsPollen (male gametophyte)Seeds (embryonic plant)(male and female gametophyte are greatly reduced in size)Two typesGymnosperms (lack flowers)Angiosperms (flowering plants)
Characteristics of Vascular Plants With Seeds
Characteristics of Gymnosperms
CYCADOPHYTACycadsLarge fernlike leavesPlants are either male or female and produce gametes in large strobilus
GinkophytaOnly one species in present day. Ginkgo bilobaAre resistant to air pollutionBear male and female cones on separate plants. Male produces pollen in strobilus-like cones. Female bears seed which develop a fleshy outer covering and resemble orange-yellow cherries. (Stinks!)
CONIFEROPHYTACone-bearing treesMost diverse of the gymnosperms: produce seeds in woody cones. Include pine, fir, spruce, juniper, cedar, redwood, yew, and larch. Form large forests and have adapted to cold and dry habitat (taiga). Protected against water loss by leaves covered with a thick cuticle (cutin) and by covering its trunk and branches with bark.Conifers are evergreensThey do loose their leaves if aged or damaged.Keeping leaves allows photosynthesis to begin at the earliest moment in spring.Found where nutrients are scarce as they eliminate need to grow a whole new set of leaves (Deciduous trees lose their leaves).
Needles and Cones
Types of Gymnosperms
Life Cycle of a pine
Can be found in the deserts or mountains of Asia, Africa and central or South America. 3 genera1. Gnetum : A tropical climbing plant2. Ephedra (Shrub-like plants and found in U. S.)i. Mormon tea Scrubby cone-bearing plant with scale-like leaves.a. Source of ephedrine: used to treat asthma, emphysema, and hayfever. 3. Welwitschia (Desert dweller with large tuberous root)i. Has only 2 leaves and may live 100 yr.
Life Cycle of Conifers
Characteristics of Angiosperms
Types of Angiosperms
Ovule Formation in an Angiosperm
Parts of a Pollen Grain
Pollen Grain Formation