1. Announcement
Quiz 5: Material from Plant Nutrition through today’s lecture
Make sure to start studying soon for the final!!!!
Form and function is very important!!!!
refer to your books or eCommons for diagrams!!!!!

2. 3rd and Last Plant of the Week
Blue Gum Eucalyptis (Eucalyptus globulus)
• Introduced to California (Exotic)
• Bark sheds off in large flakey strips
• Long slender green sickle shaped alternate leaves
• Extremely common around Santa Cruz

3. Asexual Reproduction
Vegetative reproduction:
Often the result of the
modification of vegetative organ
Some maintain sexual and
asexual reproduction

4. Asexual
PLANT REPRODUCTION
Vivipary (plantlets; modified leaves)
Bulbs (modified leaves)
Rhizomes (underground stems)
Stolons (horiz. modified stems)
all CLONAL

5. Apomictic seeds
• Asexually Produced Seeds produced in the female gametophyte
• Meiosis I w/o Meiosis II or,
• Meiosis doesn’t occur
• Gamete is diploid
• Ovule develops into seed &
Ovary develops into fruit

6. Advantage of Asexual Reproduction
• Rapid colonization of favorable environment
• No need to pollinate

7. Disadvantage to Vegetative Reproduction
• Low genetic variation
• Increased susceptibility to Disease
• Loss of entire population
Ex. Dutch Elm Disease on English Elm 1967 p.810

8. Plant Maturity
• Annuals: 1 year life cycle
• Biennials: 2 year life cycle; 2nd year reproductively mature
• Perennials: 3+ years; reproductive maturity depends on the spp.
(species)

9. Seed Dispersal
Transport of seeds away from parent plant
Major reasons for dispersal
• Decrease competition w/ relatives
• Avoid diseases
• Increase the probability for future outcrossing

10. Intraspecific Competition: Competition between individuals of the same species
Individuals of the same spp.
share similar resource
requirements
Dispersal decreases
competition with close
relatives

11. Short distance dispersal
• Annuals: Advantages
• No competition with mom
• Suitable conditions
• Annuals: Disadvantages
• Conditions can become unfavorable
• Low genetic diversity for crossing over

12. Short distance dispersal
• Perennials: Advantages
• Suitable condition
• Perennials: Disadvantages
• Conditions can become unfavorable
• Competition with mom
• Low genetic diversity for crossing over

13. Janzen - Connell Hypothesis 1970
Mechanism to explain high species diversity in te tropics
• Genetically similar organism share similar pests and pathogens
Density Dependent Mortality

14. Density Dependent Mortality
# of seeds Probability
/ unit area of Seed
Survival
Distance from parent tree->

15. Fruits
• Protect seed from damage by
animals and pathogens
• Aid in seed dispersal
• Fleshy or dry and inedible

16. 5 modes of seed dispersal
• Gravity
• Wind
• Ballistic
• Water
• Animals

17. Gravity Dispersal
• Causes fruits to fall to the ground
• Fruits can roll away and/or be consumes
• Secondary Dispersal:
Carried by water or animals at a later date
Ex. Apples, nuts, acorns, etc.

18. Wind Dispersal
Modified structures allow
seeds float on breezes or
float to the ground
Ex. Dandelion, Maple seeds

19. Ballistic Dispersal
Seeds are physically
ejected away from the
parent plant
Not very long distance,
but secondary dispersal
can increase distance
Ex. Geranium pratense

20. Water Dispersal
Seeds are
adapted to survive
being carried long
distance by
water
Ex. Coconut

21. Animal Dispersal
• Consumed and later defecated
in another place
• Cached (buried) and forgotten
• Carried inadvertently

22. Seed Dispersal: Summary
The Private Life of Plants
http://www.youtube.com/watch?v=zbQ1jWl3AOM
Minute: 0935

23. The Evolution of Angiosperms
Gymnosperms: Most recent common ancestor
What are Gymnosperms and how are they similar and different from
angiosperms?????

24. PLANT REPRODUCTION Sexual
Figure 28.5

25. Gymnosperm (“naked seed”
Seeds not protected by an ovary or fruit tissue
• Only 1,200 living spp.
• Angiosperms est. 250k-400k spp.
• Dominate the terrestrial environment 2nd to angiosperms
• ALL SHOW SECONDARY GROWTH!!!!! ( all produce wood)

26. Gymnosperm (naked seed)
• Cones are male and female reproductive structures
• Tracheids for water conduct
• ALL SHOW SECONDARY GROWTH

27. Major Groups of Gymnosperms
• Cycads
• Ginkgos
• Gnetophytes
• Conifers
Fig on p. 612 ch. 29

28. Cycads
• Most ancestral
• Found in tropics and sub tropics
• Height up to 20m
• ~300 spp.
• Often confused for Palms

29. Ginkgos
• Common during the Mesozoic era
• 250- 65 MYA
• Only one spp today Ginkgo biloba
• Male and Female Trees
• X and Y chromosomes distinguish males from females
•Similar to humans, and unlike other plants

30. Gnetophytes
• 90 spp. in 3 genera
• Only exception in Gymnosperms
• Contain Vessel Elements for xylem transport
Ex. Welwitschia

31. Conifers
• Most abundant of all Gymnosperms (700 spp)
• Forests make up largest terrestrial carbon sink
• Most spp are evergreen

32. Ex. Conifers dominate the boreal forests
Boreal Forest Cover ~ 6 mil. sq.......

33. Major Synapomorphies of Angiosperms
Synapomorphies: Shared derived traits of a group
• Double Fertilization
• Endosperm
• Ovules and seeds enclosed in a carpel
• Flowers
• Phloem with companion cells
• Reduced gametophytes