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Kingdom: Plants Photosynthetic Eukaryotes Kingdom Bacteria Kingdom Archaeabacteria 2006-2007 Common ancestor Domaine Eukaryote Plants • General characteristics • eukaryotes • autotrophs, photosynthetic • cell wall • cellulose • not mobile Transition from water to land Challenges to overcome Water conservation Internal Transport Reproduction without water Support Preventing water loss • Cuticle - waxy layer • Lipids do not dissolve in water • the cuticle creates a barrier that helps prevent the water in the plant’s tissues from evaporating into the atmosphere Plant Diversity Mosses no water transport system (pipes) Ferns water transport, no seeds Conifers pollen & seeds Flowering plants flowers & fruit seed plants water transport system colonization of land Overcoming challenges = Adaptations • Symbiosis • Tissues • Roots/stems/leaves • Horomones Seeds! • Reproduction Symbiosis • Mutualistic associations played a key role in the initial occupation of organisms on land • Mycorrihzae (fungi + plant) • • • • First plants = no roots Fungi absorbed minerals from rocks Plants now have access to minerals Fungi get free food • Commensalism • Parasitic Plant Tissue • All vascular plants have tissues • 3 types • Dermal tissue: covers plant’s entire body; serves to protect • Ground tissue: performs photosynthesis, stores water and carbohydrates, surrounds and supports the transport tissues • Vascular tissue: conducts water, minerals, nutrients and carbohydrates made by photosynthesis Vascular Tissue (vascular bundles) • Function – transport • Composed of xylem and phloem • Xylem: made of dead cells; transports water and minerals from the roots up to the leaves • Phloem: transports nutrients and carbohydrates to other parts of the plant Roots • Anchor plant in place • Absorb water/dissolved minerals from environment • Store excess food • Root hairs • Increase absorptive surface area Leaves • Composed of mesophyll tissue and veins (vascular tissue in bundles) • Leaves vary greatly in size and shape • Function of leaves • Photosythesis/energy production • Gas exchange • transpiration Leaf – external anatomy Leaf – internal anatomy • Main organs of photosynthesis in plants Vein Cuticle Epidermis Xylem & Phloem Mesophyll Epidermis Stoma Guard Cells Leaf Structures • Cuticle – waxy covering; prevents water loss through evaporation • Mesophyll – majority of leaf; contains vascular tissue; photosynthesis • Palisade • Spongy • Stomata (stoma) – tiny openings on underside of leaf; gas exchange • Guard cells – control opening and closing of stomata Leaves and Transpiration • Transpiration – water loss through evaporation Stems (shoots) • Function – support & house vascular tissue • Above ground • Main axis of plant • Structural adaptation allow plants to overcome obstacle of gravity • Connection between roots and leaves XIII. Reproduction • Seedless • Spores • Dependent on water for reproduction • Seed bearing • Seeds • Not dependent on water for reproduction Interdependence within plants • Plant systems are dependent on each other • If one fails, the rest will fail • Roots depend on sugars synthesized by photosynthetic leaves • Stems depend on water/minerals absorbed from soil by roots & sugars synthesized by leaves • Leaves depend on water/minerals absorbed by roots & support/transport of stem
