Questions Discussions: – Maria M: posting paper and questions for this week – Jon: will be picking a paper to post for next week – Peter Stevens is taking students around Orchid house at gardens at 10 am probably on Saturday. Let him or me know if you are interested. Any questions?
Whats a flower? Whats it for?
Ferns Gymnosperms Angiosperms
Flower evolution mya – Modified leaves (why?)
Whats a flower? Whats it for? Reproductive structure of angiosperms: – Heterosporangiate typically consisting of androecium, gynoecium, usually surrounded by a perianth and borne on an axis or receptacle
Flower morphology Pedicel Flower parts in whorls: (4,5s or 3s) – Calyx (sepals), Corolla (petals), Androecium (stamens with anther, filament), Gynoecium (pistils with stigma, style, ovary)
Symmetry Actinomorphic (radially symmetric) vs zygomorphic (1 bisecting line of symmetry) Asymmetric: uncommon (Cannanceae, Marantaceae)
Flower vs. Inflorescence Cercidiphyllum
Breeding systems: outcrossing and inbreeding Spatial: – Flower: perfect (both sexes) vs. imperfect (1 sex) – Plant: monoecious (1 sex) vs. dioecious (both sexes) – Heterostyly
Breeding systems: outcrossing and inbreeding Temporal: Dichogamy – Protandry: stamens before carpels – Protogyny: carpels before stamens
Pollination syndromes Animal: Insects, birds, bats – Rewards: Nectar, pollen, fragrance, oils – Attract pollinators: Scent, color patterning, mimicry (Orchidceae) Abiotic: Wind and water Self pollinated, Cleistogamous
Evolution of oil production and collection Renner and Schaefer Phil. Trans. R. Soc. B. 365: – Bees collect oil for larvae and pollinate flowers – Question: When and how often oil-offering flowers and oil-foraging bees evolved?
Oil and bees Renner and Schaefer Phil. Trans. R. Soc. B. 365: – Question: When and how often oil-offering flowers and oil-foraging bees evolved? Oil flowers evolved at least 28 times and lost times. Oldest just after the K/T boundary65 mya in America (Melpighiaceae) and Africa (Curcurbitaceae, and Laurasia (Myrsinaceae) taxa Bees evolved oil foraging at least 7 times with earliest at least Mya (but probably older)
Evolution of floral morphology
Question Is flower symmetry associated with changes in speciation rates mediated via pollinators?
Question Is flower symmetry associated with changes in speciation rates mediated via pollinators? – Suggest bilaterally symmetrical flowers can restrict pollinator access to flowers, direct pollen placement, and lead to greater reproductive isolation – Predict that bilaterally symmetrical flowers have higher speciation rates than radially symmetrical flowers
Question Is flower symmetry associated with changes in speciation rates mediated via pollinators? – Corolla symmetry data for animal pollinated families from the literature – Sister-group comparisons (40 zygomorphic clades and 19 comparisons) Building an angiosperm tree and mapping on zygomorphy Looking for the actinomorphic sister Getting number of species in family from literature
Evolution of floral morphology Zygo-Actino species * = Actino = Zygo
Question Is flower symmetry associated with changes in speciation rates mediated via pollinators? – In 15/19 comparisons zygomorphic clade was more diverse than actinomorphic clade