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plant diversity

Explore the significance of plant diversity and the impact of endemic species on our planet's health. Discover how habitat destruction, human population growth, agricultural activity, and industry and mining contribute to the loss of biodiversity. Learn about the origin and evolution of plants, including bryophytes, pteridophytes, gymnosperms, and angiosperms. Understand the ecological, aesthetic, medicinal, and economic value of different plant species.

stephanieweaver
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plant diversity

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  1. plant diversity

  2. ENDEMIC: when a species is only found in ONE specific area or habitat in the world • SA = 5th -richest country in Africa • SA = 24th-richest in the world • 3 Hotspots: 1. SUCCULENT KAROO • FYNBOS • MAPUTALAND-PONDOLAND-ALBANY

  3. Species and ecosystem diversity ensures the health of our planet. • Loss of biodiversity leads to unstable ecosystems • Also the loss of clean water, fresh air , food and medicines. • HUMAN ACTIVITIES contribute to loss of species 100 to 1000 times faster than before • Worldwide = we’re losing 70 species a day.

  4. HABITAT DESTRUCTION • Cutting down indigenous forests • Filling in wetlands • Damming up rivers • Clearing land for new settlements • When species lose habitats ….. • They are deprived of food and shelter • Isolated from others – leads to in breeding (loss of genetic diversity)

  5. HUMAN POPULATION GROWTH • Increased demand on energy, food, minerals • Using more land, water, trees, fossil fuels. Minerals, plants and animals • Increased usage – devastating effects on biodiversity • Climate change (global warming)

  6. AGRICULTURAL ACTIVITY • Indigenous, natural vegetation is cleared for cultivation and afforestation • Wetlands are filled to create more land for farming • Overgrazing destroys natural vegetation • Results in soil erosion

  7. INDUSTRY AND MINING • Industries pollute water, air and soil • Destroy natural habitats • Timber industry – loss of habitat for wildlife • Trade in wildlife- rhino horn, buchu • Invasive species (black wattle)

  8. Food and medicine for everyone • Aesthetic value • Tourism potential

  9. Bryophytes (e.g. Mosses) ORIGIN OF PLANTS Pteridophytes (e.g. Ferns, horsetails) EARLY VASCULAR PLANTS Gymnosperms (e.g. Conifers, Cycads) FIRST SEED PLANTS RADIATION OF FLOWERING PLANTS Angiosperms

  10. Presence/absence of Vascular Tissue • Presence of true roots; leaves • Spores/ seeds for reproduction • Fruit • Dependency on water for reproduction

  11. * Bryophyta(BRYOPHYTES) * Pterophyta(PTERIDOPHYTES) * SPERMATOPHYTAwith 2 groups (SPERMATOPHYTES- 2 Groups) – seed bearing 1. GYMNOSPERMS – naked seeds 2. ANGIOSPERMS- seeds enclosed in a fruit

  12. Habitat - shady places - moist * Structure - small -1 tot 5 cm - no true roots, stems leaves or vascular tissue

  13. Not well adapted for life on land • Cuticle either absent/delicate • Entire surface of plant can absorb or lose water • Thallus (primitive roots, stems and leaves) • Conducting and strengthening tissue poorly developed

  14. Peat moss (Sphagnum)

  15. Life cycle of moss plant (no detail required but must be able to identify major structures)

  16. (no detail required

  17. Pioneer plant – first to grow in new area • Plays an important role in Plant succession • E.g. mosses trap dust and organic material- organic material rots – produces acids – acids break down rock to form soil particles – seed of large tree falls on mossy carpet - germinates • Bind soil, prevent erosion • Soil richer in organic matter • Economic value – source of peat (marshland with carbonized plant material)

  18. Habitat : - Moist , shady * Structure: - Sporophyte – roots, stem (rhizome), compound leaves

  19. 2nd step in evolution • Have conducting tissue (xylem and phloem) – (strengthening and vascular) • True roots – anchor in soil + absorb water and mineral salts • Leaves and stems are differentiated (strength and support) • Parts above ground = cuticle (to reduce loss of water) • Leaves have stomata for gaseous exchange

  20. risoiede

  21. (no detail required but must be able to identify major structures)

  22. Ecological– role in plant succession, replace mosses • aesthetic – gardens, floral arrangements • Medicinal – as tea, prevent cough outbursts sap of leaf as enema (injection of liquid in rectum abscesses • Economical - tropical tree fern as building material

  23. 400 MYA • Most land plants grew in swamps (WHY?) • Depended on moist environment for reproduction • 3rd stage in evolution = breakthrough to survive in drier areas WHY? DEVELOPMENT OF SEEDS

  24. Gymnosperms (250-140 Mya) • Gametes in cones • True roots, stems and leaves • Better developed conducting and strengthening tissue • Female cones produce ovules • Male cones – produce pollen (independent of water – wind) • Seeds are naked - not protected inside a fruit • 700 spesies Angiosperms(120 Mya) • Gametes carried in flowers • True roots, stems and leaves • Better developed conducting and strengthening tissue • Produce ovules within an ovary • Mono-/ dicotolydenous • 235 000 species

  25. Habitat different types – cold , windy , dry, sandy Sporophyte – large tree, well-developed taproot system( to obtain water, anchor) Leaves - waxy layer (prevent water loss)

  26. (no detail required but must be able to identify major structures)

  27. Female Cones

  28. Evergreen – for Photosynthesis • Wood pulp + paper • Timber wood for building industry • Wood for furniture • Plantations – 53,3% surface • Resin – for varnish • Turpentine – from pine wood

  29. Building industry e.g. floor boards, roof beams • Famous antiques • Ripe fruits eaten by bats, bush pigs, birds • Birds roost in dense crown

  30. Largest group of plants (235 000 species) Habitat : - mesophytes: average amount water (most) - hydrophytes : in water - xerophytes (eg. succulents) : very dry and arid areas

  31. Sporophytes (flowering plants) have true roots, stems, leaves, flowers, fruits, seeds • Well-developed vascular system • Taproot system (store food) e.g. Beetroot • Stems (underground, store food) e.g potatoes

  32. (no detail required in any of the following diagrams but must be able to identify major structures)

  33. meeldraad stamper

  34. ginesium ovarium ovulum megaspoor mikrospoor stuifmeelkorrel Verdeel 3 keer deur mitose poolkerne Eiersel/ovum

  35. Agricultural – major food source e.g. wheat, rice, maize, potatoes • Biofuels • Economic – building material eg Eucalyptus • Cultural - thatching reeds (restios) • Aesthetic – attract tourists • Medicinal – acetyl-salicylic acid from willow bark to treat leukaemia, • Quinine from bark of cinchona tree -malaria

  36. BRYOPHYTES • No vascular tissue • No true leaves and roots • Spores • Depend on water for fertilisation PTERIDOPHYTES Vascular tissue True leaves and roots Spores Depend on water for fertilisation GYMNOSPERMS Vascular tissue True leaves and roots Seeds Fertilisation independent of water ANGIOSPERMS Vascular tissue True leaves and roots Seeds Fertilisation independent of water

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