Plant Evolution • Evolved from green algae (450 mya) • Both have same type of chlorophyll, store energy as starch, DNA similarities • Green algae ancestor • Multicellular body • Cells w/ channels to communicate • Reproduce w/ sperm & egg • Early plants • Low growth (nonvascular)
Land Adaptations cuticle • Challenge: Retain Moisture • Early plants grew near water’s edge • Those that could survive longer dry periods were favored through natural selection • Adaptations: • Cuticle: waxy coating • Stomata: pores to allow gas exchange
Land Adaptations glucose • Challenge: Transporting Resources • Adaptation: • Vascular system: tissue to transport nutrients • Up from the roots (ex: water) • Down from the leaves (ex: sugars) • Allows for taller growth water
Land Adaptations • Challenge: Growing upright • Large plants need to support own weight • Adaptation: • Lignin: hardens cell wall; gives wood strength Mortar Lignin
Land Adaptations • Challenge: Reproduction on land • Adaptations: • Pollen: carried by wind/animals • Seeds: hard coat protects embryo inside
Plant Ecology • Mutualistic relationships • Type of symbiosis where both organisms benefit • Ex: Plants (provides living space)/Bacteria (create nutrients) • Ex: Plants (provide food)/Animal (help pollinate) • Herbivore interactions • Defense adaptations • Spines, thorns, chemicals
Review • What traits do plants and plant-like protista (algae) share? • Name 4 adaptations that plants have for life on land. • Which plant adaptation allows them to carry nutrients to great heights? • Which plant adaptation allows them to retain moisture? • What is the purpose of lignin? • Explain a symbiotic relationship between plants and other organisms? • How do plants protect themselves from predators?