1. Dispersal of individuals in space: Fruits, seeds (including size, endosperm, associations with dispersers)

2. Questions Discussions: Any questions?
Jon: posting paper and questions for this week
Eliot: will be picking a paper to post for week after spring break
Any questions?

3. Seeds and fruits
What are they? What are they for?

4. Ferns
Gymnosperms
Angiosperms

5. Evolution of seeds Early land plants:
Spores -> small gametophytes -> embryo -> sporophyte
Fertilization dependent on motile sperm (like ferns)

6. Evolution of seeds Seed plants:
Heterosporic (micro and mega) -> micro and megagametophyte
Megaspore encased by sporangium when germinates
Megagametophyte encased by integument

7. Evolution of seeds
Lycopods came close but first were the pteridosperms

8. Seeds Gymnosperms: naked seed Angiosperms: enclosed seed
Enclosed in woody or fleshy cone
Angiosperms: enclosed seed
1 or 2 cotyledons
Why was enclosing gametophytes and seeds helpful?

9. Seeds Ripened ovule Embryo: diploid
Endosperm: haploid or triploid nutritive tissue (oil, starch, protein)
Seed coat: from integument
Appendages: arils, elaiosome, hair, wings

10. Fruits Fruits are ripened ovaries, seed-bearing part of the plant
Pericarp: ovary wall
Epicarp: outer
Mesocarp: middle
Endocarp: inner
Fruit morphology labile

11. Fruits Dehiscent: Capsule: >2 carpels Follicle: 1 carpel
Schizocarp: Fruit breaks into 1 carpel units

12. Fruits Indehiscent, dry: Indehiscent, fleshy:
Achene (variants include nuts)
Indehiscent, fleshy:
Berry: seed(s) surrounded by fleshy pericarp
Drupe: seeds(s) surrounded by a stony endocarp

13. Fruit Simple: 1 or more carpels with one pistil
Aggregate: 1 flower with >1 pistil
Multiple: >1 flower

14. Fruits
Facilitate dispersal:
Abiotic: explosive, wind, water

15. Fruits Facilitate dispersal: Biotic: Hitch rides
Attract disperser via fruit
Attract disperser via seed
Attract disperser via appendages

16. Evolution of seed size
Ove Eriksson

17. Variation in seed size
Seed size: 1011

18. Evolution of seed size

19. Questions
Why did larger seeds evolve? What is biotic dispersal related to larger seeds?
Patterns over time:
Cretaceous (124 mya): small seeds (<1 mm3) and little biotic dispersal
Early tertiary (65-38 mya): increase in seed size mean and range and biotic dispersal
Late tertiary (38-2 mya): decrease in seed size mean but not range (cooler climate and open vegetation)

20. Questions
Why did larger seeds evolve? What is biotic dispersal related to larger seeds?
Other patterns:
Biotic dispersal, typically larger seeds
Taller growth forms, typically larger seeds

21. Questions
Why did larger seeds evolve? What is biotic dispersal related to larger seeds?
Hypotheses
Coevolution? Diversification of mammals and birds -> closed canopy vegetation
Recruitment? Change in climate and loss of large herbivores -> closed canopy vegetation (light competition)
Life form? Change to closed canopy forest -> larger and longer-lived plants, longer as juveniles

22. Evolution of seed size

23. Evolution of seed size

24. Evolution of seed size

25. Questions
Why did larger seeds evolve? What is biotic dispersal related to larger seeds?
Hypotheses
Coevolution? Maybe primates, ungulates, and rodents not birds and bats. But why large seeds?
Recruitment? Environmental shifts compatible
Life form? Environmental shifts compatible
Conclusions
Some of all three