1. Chapter 6 Simpson, 2nd Edition
Angiosperm Evolution
Chapter 6
Simpson, 2nd Edition

2. Major Evolutionary Advances
Life - 3,800 mya
Prokaryotic cell/autotrophic
1. Earth
2. Prokaryotes
3. Eukaryotes
4. Multicellular life
5. Vascular tissue
6. Seeds
7. Flowers
Eukaryotic cell - 1,400 mya
Multicellar plants - 1,000 mya
Vascular tissue mya
Needed on land - why?
Seeds mya
Flowers – 130 mya
Earth
Forms
Prokaryotic
Cells
Eukaryotic
Cells
Multicellular
Plants
Vascular
tissue
Flowers
5,000
mya
4,000
3,000
2,000
1,000
Seeds

3. Timeline Devonian Period Devonian-Carboniferous Mesozoic
400mya – 1st vasc plts
Psilotum – like
Devonian-Carboniferous
ferns, lycophytes, sphenophytes & progymnosperms
Mesozoic
gymnosperm-dominant seed plants
Cretaceous Period
130 mya 1st fossil flowers
90 mya - worldwide angiosperm dominance

4. Relationships of Angiosperms
Bennettitales and Genetophytes – 225 mya

5. Relationships of Angiosperms

6. Systematics phylogeny represented by cladogram (phylogenetic tree
branching diagram that conceptually represent the evolutionary pattern of descent
lines represent lineages, with implied time scale
branch = divergence
ancestral = preexisting
apomorphy = derived (evolutionary novelty)

7. Systematics Phylogenetic Systematics (cladistics)
methodology to infer evolutionary history using apomorphies
recognizes monophyletic groups (= clade)
Phylogenetic Classification Scheme can result
avoids:
paraphyletic groups
com anc but not all descendants
polyphyletic groups
two or more sep groups with sep anc

8. Angiosperm Systematics
What conclusions can be drawn from this cladogram?

9. Angiosperm Apomorphies
flower, usually with perianth

10. Angiosperm Apomorphies
stamens with 2 lateral thecae, each composed of 2 microsporangia
reduced, 3-nucleate male gametophyte

11. Angiosperm Apomorphies
carpels and fruit formation
conduplicate (inwardly folded longitudinally & along the central margin) megasporophyll bearing 2 adaxial rows of ovules
carpel body encloses seed (angiosperm name origin)

12. Angiosperm Apomorphies
ovules with 2 integuments
bitegmic with micropyle at distal end

13. Angiosperm Apomorphies
reduced, 8-nucleate female gametophyte

14. Angiosperm Apomorphies
reduced, 8-nucleate female gametophyte:
evolution of female gametophyte

15. Angiosperm Apomorphies
endosperm formation
product of double fertilization
zygote = 1 sperm + egg
endosperm = 1 sperm + polar nuclei

16. Angiosperm Apomorphies
sieve tube members
sieve plates – contain pores at end walls larger than lateral pores
sieve cells are primitive sugar-conducting cells
vessels found in all but primitive angiosperms

17. Origin of Angiosperms Archaefructus 130 mya northern China
reconstruction of Archaefructus sinensis
fossil imprint of Archaefructus lianogensis

18. Four evolutionary trends among flowers
floral parts many -> few
floral whorls from 4, long floral axis, separate parts -> reduced whorls, short floral axis, fused parts
superior -> inferior ovary
symmetry radial -> bilateral

19. reduced whorls, short floral axis, fused parts
Lonicera (honeysuckle)
Vanilla (vanilla bean orchid)
Nelumbo (Lotus)
Helianthus disk floret
Anemone
floral parts few
reduced whorls, short floral axis, fused parts
inferior ovary
bilateral symmetry

20. Order Asterales Asteraceae (=Compositae) Sunflower Family 1620 genera
23,600 species
most diverse dicot family
98% herbaceous, but shrubs, trees or vines also
inflorescence a head, subtended by involucre of phyllaries
K 0-∞ C (5) [4] or (3) A (5) [(4)] G (2) inferior

21. Order Asterales Asteraceae (=Compositae) p. 429 Fig. 8.131
Sunflower Family
1620 genera
23,600 species

22. Order Asterales Asteraceae (=Compositae) p. 430 Fig. 8.132
Sunflower Family
1620 genera
23,600 species

23. Order Asterales Asteraceae (=Compositae) p. 431 Fig. 8.133
Sunflower Family
1620 genera
23,600 species

24. Order Asterales Asteraceae (=Compositae) p. 432 Fig. 8.132
Sunflower Family
1620 genera
23,600 species