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
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