seed formation - outer cell layers of ovule form seed coat

• postpones development until more favorable conditions
• protects young plant when it’s the most vulnerable
• keeps stored food that keep young plant alive
• adapted for dispersal
• seed coat forms >> metabolic activities stop
  • germination can’t start until water/oxygen reaches embryo
• seeds don’t germinate until appropriate conditions (heat, available nutrients, chemicals, pass through animal intestines, etc)
  • scarification - breaking down seed coat so that first root can emerge

fruit formation - helps angiosperm embryos survive

• develops from flower ovary
• different fruit types due to 3 layers (epicarp, mesocarp, endocarp) on ovary wall
  • follicles - split along 1 carpel edge
  • legumes - split along 2 carpel edges
  • samaras - not split, has wing
  • drupes - single seed in hard pit
  • true berries, more than 1 seed, thin skin
  • hesperidia - more than 1 seed, leathery skin
  • aggregate fruits - derived from multiple ovaries
  • multiple fruits - develop from flower cluster
• fruit dispersal - mostly transferred by animals
  • fruits of maples, elms, ashes have wings >> distributed by wind
  • dandelions have light seeds >> wind distribution
  • coconuts, beach plants distributed by water