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Chapter 8 - Plants Ms. Van Sciver’s Grade 7.

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Presentation on theme: "Chapter 8 - Plants Ms. Van Sciver’s Grade 7."— Presentation transcript:

1 Chapter 8 - Plants Ms. Van Sciver’s Grade 7

2 Plants Autotrophs – make their own food Multicellular Eukaryotes – have a nucleus Cells surrounded by cell walls.

3 Plant Origins

4 Land Adaptations Support Rigid cell walls Vascular tissue Reproduction
Gametophyte – Reproductive cells Sporophyte – Spores Zygote – fertilized egg Obtaining Water Non vascular – must contact water Vascular – tubes for water transport Retaining Water Cuticle Transporting Materials Non-vascular – diffusion/osmosis Vascular – tubelike tissue

5 Plant Life Cycle

6 Seedless Plants Non-Vascular - Bryophytes
Low Growing Materials transport from cell to cell Live in damp shady places Thin cell walls

7 Bryophyte Life Cycle

8 Non-Vascular - Mosses More than 10,000 species Gametophyte –
green- fuzzy appearing tiny leave like parts Root like structures – rhizoid Sporophyte stalk capsule contains spores

9 Non-Vascular - Liverworts
More than 8,000 species Found – moist rocks along streams Gametophyte – “liver” shaped Sporophytes – too small to see in umbrella shaped stalk

10 Non-Vascular - Hornworts
Fewer than 100 species Found in moist soil Sporophytes – slender, horn shaped

11 Seedless Plants – Vascular
Ferns Horsetails Club Mosses True Vascular Tissue Release Spores Need water for reproduction

12 Ferns More than 12,000 species True Roots, stems, leaves Sporophyte
Leaves – Fronds Spore cases Gametophytes Tiny Grow low to ground

13 Fern Life Cycle

14 Horsetails Few Species alive now Needle Like Branches Small leaves
grow in circle around joints Small leaves grow flat against stem Stem contains Silica

15 Club Mosses Only a few hundred species Resembles branch of a pine tree
Ground pine Grows in spiral around stem

16 Seed Plants Have Vascular Tissue Use Pollen and Seeds to reproduce
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

17 Seed Structure Monocot – one cotyledon (seed leaf)
Dicot – 2 cotyledons

18 Seed Dispersal Seeds must be dispersed to prevent competition
Water Sunlight Minerals Dispersed by Wind Animals

19 Germination Needs- correct moisture, correct temperature, correct time – some seeds are dormant first

20 Roots 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 Xylem Phloem Fibrous Roots - spreading Taproot - deep

21 Stems Xylem – carries mineral, water Phloem – carries food Supporting Cells Woody Stems Outer bark – Cork Living Phloem Cambium Living Xylem Sapwood Hardwood Annual Rings Herbaceous Soft No wood

22 Leaves Conduct Photosynthesis Lose water from stomates during transpiration Guard cells control amount of water lost

23 Gymnosperms Ginkgo Seed Not Protected by a fruit Needle like or scale like leaves Deep roots system Cycad tropical Conifer Largest group Cone bearing Gnetophyte Deserts, tropical rain forests Can live 1,000 yrs.

24 Gymnosperm Reproduction
Pollination pollen - male parts Fertilization sperm reaches ovule Seed development Seed Dispersal

25 Angiosperms Produce Flowers Seeds are protected by fruits Live almost

26 Flower Parts

27 Angiosperm Life Cycle

28 Dicots vs. Monocots

29 Tropisms A plant grows toward a stimulus – positive A plant grows away from a stimulus – negative Touch – Thigmotropism Light – Phototropism Gravity – Gravitropism or Geotropism Hormones – Auxin – causes cells to lengthen on side away from light. Plant bends toward light.

30 Seasonal Changes Photoperiodism – response to length of day vs. night.
Critical Night Length Short Day Plants – Bloom when daylight is shorter autumn Long Day plants – Bloom when daylight is longer – spring and summer Day Neutral – No effect

31 Life Spans of Angiosperms
Annuals Complete cycle in one growing season herbaceous stems Biennials Year one – stems, leaves Year Two – flowers, fruits, seeds Perennials Flower every year Most have woody steam some have herbaceous stems leaves and stems die each winter, but new are produced in spring.

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