KEY CONCEPT Plant life began in the water and became adapted to land. Plant Evolution

Land plants evolved from green algae (450 mya) –B–Both have same type of chlorophyll, store energy as starch, DNA similarities Green algae ancestor –M–Multicellular body –C–Cells w/ channels to communicate –R–Reproduce w/ sperm & egg Early plants –L–Low growth (nonvascular)

True plants evolved through natural selection. –True plants have embryos that develop while attached to female parent. –Ancestral charophyceans lived in areas of shallow water. –Those that could survive longer dry periods were favored. –First true plants probably grew at edges of water.

Land Adaptations stoma Challenge = Retaining Moisture – Early plants grew near waters edge Adaptation: – Cuticle: Waxy coating – Stomata: Pores to allow gas exchange

Land Adaptations Challenge = Transporting Resources Adaptaion: – Vascular system: tissue to transport nutrients Up from the roots (ex: water) Down from the leaves (ex: sugars) – Allows taller growth water glucose

Land Adaptations Challenge = Growing Upright Adaptation: – Large plants need to support own weight – Lignin: hardens cell wall; gives wood strength

Challenge = Reproduction on Land Adaptation: – Pollen: Allow for reproduction without free-standing water. Can be carried by wind/animals. – Seeds: Hard coated storage device for a plant embryo. Protects embryos from drying wind and sunlight. – Embryo then develops when environment is favorable. Land Adaptations

Plant Ecology Mutualistic relationships – Type of symbiosis where both organisms benefit – Ex: Plants (provides living space)/Bacteria (create nutrients) – Ex: Plants (provide food)/Insects (help pollinate) Herbivore interactions – Defense adaptations – Spines, thorns, chemicals

REview 1)What traits do plants and plant-like protista (algae) share? 2)Name 4 adaptations that plants have for life on land. 3)Which plant adaptation allows them to carry nutrients to great heights? 4)Which plant adaptation allows them to retain moisture? 5)What is the purpose of lignin? 6)Explain a symbiotic relationship between plants and other organisms? 7)How do plants protect themselves from predators?