1. FLOWERS !

2. Land Plants Review Moist Dry environments
1) Swimming sperm (club moss, horsetails, ferns)
2) Airborne pollen + swimming sperm (few gymnosperms)
3)Airborne pollen (gymnosperms & angiosperms)
4) Animal borne pollen (angiosperms)

3. Brief History of Land Plants
~470 MYA 1st Land Plants
300 MYA species-club mosses, horsetails, ferns, gymnosperms
150 MYA 3,000 species mostly gymnosperms
90 MYA ,500 species—mostly angiosperms
Today ,000 species—mostly angiosperms

4. 5 STAGES OF LAND PLANT EVOLUTION

7. 5 STAGES OF LAND PLANT EVOLUTION

10. 5 STAGES OF LAND PLANT EVOLUTION

12. 5 STAGES OF LAND PLANT EVOLUTION

14. 5 STAGES OF LAND PLANT EVOLUTION

16. What do you conclude from these data?
Why have angiosperms been so successful compared to gymnosperms?
What do you conclude from these data?

17. Why have angiosperms been so successful?
Adaptations to dry land
Rapid reproduction cycle & Early maturity
Flowers with
Well protected and well-nourished seeds
Efficient seed dispersal mechanisms
Efficient pollination
Recall the evolution of sperm transfer
Animals especially
Insects
Water
Air
(wind)

18. But first animals on land were arthropods.
First insect fossils ~ 470 mya at the same time as the first land plants colonized land.
First flying insects ~325 mya.
Major diversification of insects (bees, flies, butterflies & moths) ~150 mya occurred along with the radiation of flowering plants

19. Phylum Angiosperms ( Flowering Plants)
Two major classes
Monocotylendonae
Eudicotyledonae

20. Types of Flowers Complete Flowers (Perfect Flowers)= flowers with all
of the usual male
and female parts

24. Double Fertilization
Triploid Endosperm (3n)

25. Fruit Formation

26. SEEDS Eu

27. Types of Flowers Cont’. Incomplete Flowers (Imperfect Flowers) =
Flowers with one or more basic parts missing
e.g. Pistillate flowers have only female pistil
e.g. Staminate flowers have only male stamen

28. Corn with incomplete flowers

29. Flower Symmetry Radial Symmetry (Circular & disk-like)
Line through the center in any direction forms identical halves. (Attracts general pollinators)

30. Tallest Flower Has Radial symmetry “Corpse Flower”
Amorphophallus titanum

31. Largest Blossom
Rafflesia arnoldii

32. Flower Symmetry Bilateral Symmetry
Line through the center in one direction can produce mirror images.
(These flowers
attract
specific
pollinators)

33. Composite Flowers. = Flowers grouped together into
Composite Flowers = Flowers grouped together into clusters to produce a showy display

34. Head of a sunflower

35. Pollination Wind Pollination –earliest pollination
Characteristics of wind pollinated flowers
Unisexual flowers—encourages outbreeding
Monoecious= corn, oak, melons
Dioecious= willows, poplars, maples, spinach, asparagus

36. Wind pollination in angiosperms (grasses)
Characteristics of wind pollinated flowers:
Small inconspicuous
Without petals
No scent or nectar
Large quantity of pollen produced

37. Animal Pollination Many types of animals involved:
85% of flowers pollinated by insects (bees, butterflies, beetles, flies, ants); they get pollen and nectar.
Birds and a few small mammals especially bats
Less pollen needs to be produced than in wind pollination
Flowers are bisexual—increases efficiency

38. Generalist vs. Specialist Strategies
Generalist Flowers—attract many pollinators
Specialist—attracts only one pollinator
Disadvantage –flower and pollinator are dependent upon one another
Benefit for plant—prevents waste of pollen & nectar for inefficient pollination
Benefit for pollinator—monopoly of food source

39. The Co-Evolution of Flowers and their Pollinators

40. Attracting Pollinators
Color & UV & electric patterns
Nectar guides—lines of color that “guide” the pollinator to the nectaries (glands that produce the sugar water)
Fragrance—scent glands
Sex

41. Bee Flowers Flowers open during day Bees visit many species
Some flowers are specialized
only for bees

42. Buzz Pollination
Some bee species grab tubular anthers & vibrate flight muscles and shake the pollen out of pore at the end.

43. Nectar Guides

44. Ultraviolet Light Patterns
Dandelion

45. Ultraviolet Light Patterns
Silverweed

46. Sex Flower that mimics female bees by color and scent to
attract male bees.
Bee orchid

47. Bird Flowers (e.g. hummingbird)
Color red or orange
Produce lots of nectar
Flowers large and shaped as tubes or funnels, cups or flasks.
Lack odor

48. Bat Flowers Nocturnal flowers Pale color Strong scent Bats with long
Nose and tongue. Some hover, some don’t

49. Fly Flowers Flies are second most common pollinators
Smell is primary attractant
Color yellow, green, white, can be mottled and look & smell like rotting meat

50. Butterfly Flowers Diurnal Bright colors Smell modest Petals fused
into long tubes
for proboscis

51. Moth Flowers Flowers are nocturnal Pale color Strong sweet smell
Petals fused into long tubes for long proboscis

52. The case of the hawk moth and the iris

53. Hawkmoths & the S. African Iris
Hawkmoths are important pollinators!
S. African Iris produces nectar inside a flower tube as a reward for pollinators.
The ‘flower tube’ can vary in length.
How does the Hawkmoth
pollinate?...
Open Source Photo Credit:

54. How do hawkmoths pollinate S. African iris?
Hawkmoths stick their long tongues inside the flower tube to collect the nectar.
When their tongue is inside, the the pollen from the stigma sticks to the head of the hawkmoth.
When they visit a new flower, they transfer the pollen from previous plant visits.
Tongue length
Open Source Photo Credit:
Flower tube length

55. Distribution of flower tube length

56. Distribution of moth tongue lengths

57. Question : what kind of selection do you think hawkmoth tongue length will have on flower tube length? A B C
Short flower tube length Long

58. Other Pollinators:
Mouse