PLANT REPRODUCTION QUESTION 1990:			L. PETERSON/AP BIOLOGY

	Discuss the adaptations that have enabled flowering plants to overcome the
	following problems associated with life on land.

	a.  The absence of an aquatic environment for reproduction
	b.  The absence of an aquatic environment to support the plant body
	c.  Dehydration of the plant

  
     
  STANDARDS:
  
  A.  ABSENCE OF AN AQUATIC ENVIRONMENT FOR REPRODUCTION:   Max. = 4 points
  __  Flowers - attraction for insects - shape, color, smell, chemical, nectar.
               Mimicry for pollination (coevolution)
  __  Timing of reproduction
  Male
  __  Microspores - pollen / Reduced Gametophyte
  __  Lack of motility of gamete - pollen grain modification for transport
                    e.g. light weight/structure
  __  Pollination - transport of male gametes, wind, insects (self-pollination)
  Female
  __  Reduced gametophyte (in megaspore or megasporangium)
  __  Protected gametophyte - embryo inside ovary, carpel, pistil
  __  Evolution of seed
  __  Fertilization - internal - pollen tube, endosperm
  __  Fruit and seed dispersal
  __  Seed dormancy
  
  B.  ABSENCE OF AN AQUATIC ENVIRONMENT TO SUPPORT THE PLANT BODY:  Max. = 4
  points
  __  Stem - support
  __  Root - anchorage
  __  Vascular tissue - xylem fibers, tracheids, vessels, heartwood, dead tissues, phloem 
           fibers or Vascularization
  __  Vines, Tendrils
  __  Cell wall - lignin, cell wall support, cellulose
  __  Cambium - secondary thickening
  __  Sclerenchyma - whole wall support
  __  Collenchyma - corner wall support
  __  Prop, buttressed roots
  __  Turgor pressure
  
  C.  DEHYDRATION OF THE PLANT:                          Max. = 4 points
  __  Root hair, absorption
  __  Cuticle, wax, acellular
  __  Bark - suberin, cork
         Scales - bud protection
         Sepal/petals - floral part protection
  __  Seed coat / Pollen grain wall
  __  Stomates - function to control water movement
  __  Xylem - water transport
  __  Leaf/stem/root modifications (2 points max.) 
     surface area reduction in desert plants/succulents
     stomates under surface
     leaf rolling
     hairs and trichomes
     interlocked epidermal cells
     hypodermis
     cortex - water storage or retention
     loss of leaves / abscission layer
  __  CAM/C4 plants - modified stomate functions
  __  seed dormancy (if not mentioned in part A)