1. The Evolution of The FlowerBy
Brea Bowers and
Jenna Eakes

2. The Basic Flower Bisexual reproductive axis with carpels and stamens
Female parts
Pistil- stigma, style, and ovary
Stigma- sticky bulb on the pistil that receives the pollen
Style- long stalk that the stigma sits on top of
Ovary- holds the seeds inside that turns into the fruit; contains ovules
Ovule- part of the ovary that become the seeds

3. The Basic Flower Male parts Stamen- filament + anther
Anther- produces and contains pollen
Filament- the fine hair-like stalk that the anther sits on top of

4. The Basic Flower Other Important Parts of a Flower
Petal- The colorful, often bright part of the flower; attracts pollinators
Sepal- The parts that look like little green leaves that cover the outside of a flower bud to protect the flower before it opens

5. The Basic Flower

6. Evolution Phyllotaxis- the arrangement of leaves on the stem
Merosity- the number of sepals in the calyx of the flower
Whorled phyllotaxis- Nerium oleander
The Lady Tulip (Tulipa clusiana) trimerous

7. Bilateral Symmetry-Orchid
Evolution
Perianth-Petals(Corolla) + Sepals(Calyx)
Symmetry- defined by the petals
Bilateral Symmetry-Orchid

8. The Fossil Record
The fossil record indicates that angiosperms date back to the Cretaceous period
Around mya
The closest possibility of the earliest angiosperms is around 132 mya
There is a slight possibility that angiosperms could have existed even before this time.

9. The Fossil Record Continued…
One theory states that angiosperms first evolved in the tropics such as hills and uplands
No fossilization can occur in these areas
Angiosperms could have existed before the Cretaceous period
The first angiosperm fossils existed in the lowlands

10. Genes
KANADI genes

11. Evolution of Carpel and Ovule
The petals evolved from the stamen or leaves
The sepals evolved from the leaves
The carpel of the flower folded inward and fused to make a pistil
A compound pistil is when several carpels fuse together
Evolution of the Carpel and Ovule

12. Amborella

13. Evolution of the Carpel and Ovule
The ovules of angiosperms look very similar to the cupules of the gymnosperm, Caytonia.
Caytonia (order Caytoniales) is an extinct gymnosperm known as the “Mesozoic seed ferns”
In Caytonia, the ovules are in rows of two instead of one row like angiosperms

14. Evolution of the Carpel and Ovule
In order for the Caytonia cupule to resemble the angiosperm ovule, a reduced number of rows must exist in the angiosperm ovule
Explanations for this change seem to point in the direction that this change happened before the angiosperm radiation.
The angiosperm radiation happened during the Cretaceous Period and was a time during which several different angiosperms began to exist in the fossil record. This was a time when several basal angiosperms became extant.

15. Caytonia

16. Amborella “Sister” species of the angiosperms
Functional female flowers with staminodes
Staminodes- transition between stamens and carpals

17. Similar to the present day, sweet gum tree
Angiosperm fossil
Similar to the present day, sweet gum tree

18. Sunflower

19. Works Cited
“Flower Evolution: The Origin and Subsequent Diversification
of the Angiosperm Flower” By: Chelsea D. Specht and Madelaine E. Bartlett
Amborella:
Small Sunflower:
Large Sunflower:

20. Works Cited Cont.

21. Works Cited Cont.