chapter 8 - plants
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Chapter 8 - Plants. Ms. Van Sciver’s Grade 7. Plants. Autotrophs – make their own food Multicellular Eukaryotes – have a nucleus Cells surrounded by cell walls. . Plant Origins. Land Adaptations. Support Rigid cell walls Vascular tissue Reproduction Gametophyte – - PowerPoint PPT PresentationTRANSCRIPT
Ms. Van Sciver’s Grade 7
Chapter 8 - Plants
Autotrophs – make their own foodMulticellularEukaryotes – have a nucleusCells surrounded by cell walls.
Plants
Plant Origins
Obtaining Water•Non vascular – must contact water•Vascular – tubes for water transport
Retaining Water•CuticleTransporting Materials•Non-vascular – diffusion/osmosis•Vascular – tubelike tissue
Land AdaptationsSupport• Rigid cell walls• Vascular tissueReproduction•Gametophyte –•Reproductive cells
• Sporophyte –• Spores
•Zygote – fertilized egg
Plant Life Cycle
Low GrowingMaterials transport from cell to cellLive in damp shady placesThin cell walls
Seedless PlantsNon-Vascular - Bryophytes
Bryophyte Life Cycle
Non-Vascular - MossesMore than 10,000 speciesGametophyte – green- fuzzy appearing tiny leave like parts Root like structures –
rhizoid
Sporophytestalkcapsule contains
spores
Non-Vascular - LiverwortsMore than 8,000 speciesFound – moist rocks along streams Gametophyte – “liver” shapedSporophytes – too small to see in umbrella shaped stalk
Fewer than 100 speciesFound in moist soilSporophytes – slender, horn shaped
Non-Vascular - Hornworts
• Ferns• Horsetails• Club Mosses• True Vascular
Tissue• Release Spores• Need water for
reproduction
Seedless Plants – Vascular
• More than 12,000 species
• True Roots, stems, leaves
• Sporophyte• Leaves – Fronds• Spore cases• Gametophytes• Tiny• Grow low to
ground
Ferns
Fern Life Cycle
• Few Species alive now
• Needle Like Branches
• grow in circle around joints
• Small leaves • grow flat against
stem• Stem contains Silica
Horsetails
• Only a few hundred species
• Resembles branch of a pine tree• Ground pine• Grows in spiral around
stem
Club Mosses
• Have Vascular Tissue• Xylem – carries water and minerals• Phloem – carries food (sugars)• Use Pollen and Seeds to reproduce• Pollen – male reproductive cell• Seeds – embryo, food supply, seed coat
Gymnosperms• Seeds not protected by fruit
Angiosperms• Produce Flowers• Seeds protected by fruit
Seed Plants
Seed StructureMonocot – one cotyledon (seed leaf)Dicot – 2 cotyledons
• Seeds must be dispersed to prevent competition
• Water• Sunlight• Minerals• Dispersed by• Wind• Water• Animals
Seed Dispersal
Needs- correct moisture, correct temperature, correct time – some seeds are dormant first
Germination
• Tip Covered by a root cap• Protects root during growth• New cells develop behind
root cap• Root hairs• Tiny• Absorb water, minerals• Anchor plant in soil
Roots
• Xylem• Phloem• Fibrous Roots -
spreading• Taproot - deep
Xylem – carries mineral, waterPhloem – carries foodSupporting Cells
Stems
HerbaceousSoftNo wood
Woody StemsOuter bark – CorkLiving PhloemCambiumLiving XylemSapwoodHardwoodAnnual Rings
Conduct Photosynthesis
Lose water from stomates during transpiration
Guard cells control amount of water lost
Leaves
Gymnosperms Ginkgo
ConiferLargest groupCone bearing
Cycadtropical
GnetophyteDeserts, tropical rain forestsCan live 1,000 yrs.
Seed Not Protected by a fruitNeedle like or scale like leavesDeep roots system
Gymnosperm Reproduction
Pollination pollen - male parts
Fertilization sperm reaches ovule
Seed development
Seed Dispersal
Produce FlowersSeeds are protected by fruits
Angiosperms
Live almost everywhere
Flower Parts
Angiosperm Life Cycle
Dicots vs. Monocots
A plant grows toward a stimulus – positiveA plant grows away from a stimulus – negativeTouch – ThigmotropismLight – PhototropismGravity – Gravitropism or Geotropism
Hormones – Auxin – causes cells to lengthen on side away from light. Plant bends toward light.
Tropisms
• Photoperiodism – response to length of day vs. night.• Critical Night Length • Short Day Plants – Bloom when daylight is shorter
autumn
Seasonal Changes
• Long Day plants – Bloom when daylight is longer – spring and summer
• Day Neutral – No effect
Perennials• Flower every year• Most have woody steam• some have herbaceous stems• leaves and stems die each winter, but
new are produced in spring.
Life Spans of Angiosperms• Annuals
Complete cycle in one growing season
herbaceous stems• Biennials
Year one – stems, leaves
Year Two – flowers, fruits, seeds