Plant Evolution Plant Evolution Evolved from green algae

Plant Evolution

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 water • 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

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

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 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?