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PLANTS. Plants: Grouped by characteristics. Nonvascular Simple; most grow in moist places No vascular tissues. No way to move around water and nutrients Need to live close to water Mosses, liverworts, ferns Evolved first Vascular Have Vascular tissues: roots, stems and leaves
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Plants: Grouped by characteristics • Nonvascular • Simple; most grow in moist places • No vascular tissues. • No way to move around water and nutrients • Need to live close to water • Mosses, liverworts, ferns • Evolved first • Vascular • Have Vascular tissues: roots, stems and leaves • Allows them to grow large and in many different environments • Includes trees, flowering plants, crops, etc….
Non vascular = Bryophytes • Only nonvascular plants (mosses, liverworts) • no ability to internally transport water and materials • requires moist environment • live in colonies, has rhizoids to anchor it • important in soil formation
Vascular Plants - Tissues Plants have 3 tissue systems: • Ground tissue • Photosynthesis, food storage, regeneration, support, protection • Vascular tissue (xylem and phloem) • Movement of materials • Dermal tissue (exterior) • Protection and prevention of water loss
Plants: Stems • Function of stems • Support, transport of water & food • Green • Woody • Transport of materials • xylem - conducts water and minerals • phloem - conducts food
Growth • Plant growth occurs at specialized areas called meristems (meristematic tissue) • Primary growth = growth in length • Secondary growth = growth in girth
Leaf function • Photosynthesis - more later • Transpiration - 99% of water absorbed by plant is lost by transpiration • Stomata are tiny holes on the bottom of the leaf that let gases and water in and out • Opening controlled by guard cells
Photosynthesis • Uses carbon dioxide, water, and sunlight - reactants • Releases oxygen and makes sugar, oxygen is released - product chlorophyll – the green substance found in plants that traps energy from the sun and gives plants their green color chloroplasts -where photoysynthesis happens
Plant Evolution • First = Bryophytes - no roots, leaves or stems, no vascular system, simple reproduction relying on water. Second = Ferns - first vascular system • Reproduce using spores
Gymnosperms • Vascular, seed bearing, flowerless plants • means “naked seed” • largest division is conifers • leaves are called needles • Pines, cedars, spruces, firs
Angiosperms • Flowering, vascular plants • Most successful plants: deciduous trees • Magnolias, roses, apple trees • Plant Parts • Pistil – part of a flower that makes the eggs that grow into seeds • Stamen – part of a flower that makes pollen • Pollen– tiny grains that make seeds when combined with a flower’s egg monocot seed – a seed that has one seed leaf and stored food outside the seed leaf dicot seed – a seed that has two seed leaves that contain stored food
Plant Adaptations • Specialized tissues – vascular tissues • Cuticles • Waxy coating on surfaces • resists drying out • stomata exist to allow necessary gas exchange • Alternation of generations • Plants live part of their life in a haploid stage and part in a diploid stage • haploid portion = gametophyte • diploid portion = sporophyte • Co-evolution with pollinators