1. Chapter 30 Plant Diversity II

2. Chapter 30: Plant Diversity II
Fig. 29-7
Chapter 30: Plant Diversity II 1
Origin of land plants (about 475 mya) 2
Origin of vascular plants (about 420 mya) 3
Origin of extant seed plants (about 305 mya)
Liverworts
Nonvascular
plants
(bryophytes)
Land plants
ANCES-
TRAL
GREEN
ALGA 1
Hornworts
Mosses
Lycophytes (club mosses,
spike mosses, quillworts)
Seedless
vascular
plants 2
Vascular plants
Pterophytes (ferns,
horsetails, whisk ferns)
Figure 29.7 Highlights of plant evolution
Gymnosperms 3
Seed plants
Angiosperms
500
450
400
350
300 50
Millions of years ago (mya)

3. What are five crucial adaptations that led the success of seed Plants?
Seeds
Reduced gametophytes
Heterospory
Ovules
Pollen

4. Seeds
Seeds changed the course of plant evolution, enabling their bearers to become the dominant producers in most terrestrial ecosystems
A seed consists of an embryo and nutrients surrounded by a protective coat

5. Reduced Gametophyte: protection of antheridia and archegonia
Fig. 30-2
PLANT GROUP
Mosses and other nonvascular plants
Ferns and other seedless vascular plants
Seed plants (gymnosperms and angiosperms)
Reduced, independent (photosynthetic and free-living)
Reduced (usually microscopic), dependent on surrounding sporophyte tissue for nutrition
Gametophyte
Dominant
Reduced, dependent on gametophyte for nutrition
Sporophyte
Dominant
Dominant
Gymnosperm
Angiosperm
Sporophyte (2n)
Microscopic female gametophytes (n) inside ovulate cone
Microscopic female gametophytes (n) inside these parts of flowers
Sporophyte (2n)
Gametophyte (n)
Example
Figure 30.2 Gametophyte/sporophyte relationships in different plant groups
Microscopic male gametophytes (n) inside these parts of flowers
Microscopic male gametophytes (n) inside pollen cone
Sporophyte (2n)
Sporophyte (2n)
Reduced Gametophyte: protection of antheridia and archegonia
Gametophyte (n)

6. Heterospory: The Rule Among Seed Plants
The ancestors of seed plants were likely homosporous, while seed plants are heterosporous
Megasporangia produce megaspores that give rise to female gametophytes
Microsporangia produce microspores that give rise to male gametophytes

7. Ovules and Production of Eggs
An ovule consists of a megasporangium, megaspore, and one or more protective integuments
Immature female cone
Integument
Spore wall
Megasporangium (2n)
Megaspore (n)
(a) Unfertilized ovule

8. Pollen and Production of Sperm
Microspores develop into pollen grains, which contain the male gametophytes
Pollination
Pollen eliminates the need for a film of water and can be dispersed great distances by air or animals
If a pollen grain germinates, it gives rise to a pollen tube that discharges two sperm into the female gametophyte within the ovule
Seed coat (derived from integument)
Integument
Female gametophyte (n)
Spore wall
Egg nucleus (n)
Immature female cone
Food supply (female gametophyte tissue) (n)
Male gametophyte (within a germinated pollen grain) (n)
Megasporangium (2n)
Discharged sperm nucleus (n)
Embryo (2n) (new sporophyte)
Megaspore (n)
Micropyle
Pollen grain (n)
(a) Unfertilized ovule
(b) Fertilized ovule
(c) Gymnosperm seed

9. The Evolutionary Advantage of Seeds
A seed develops from the whole ovule
A seed is a sporophyte embryo, along with its food supply, packaged in a protective coat
Seeds provide some evolutionary advantages over spores:
They may remain dormant for days to years, until conditions are favorable for germination
They may be transported long distances by wind or animals

10. Gymnosperms What are the four phyla of gymnosperms?
Fig. 30-UN1
Gymnosperms
Nonvascular plants (bryophytes)
Seedless vascular plants
Gymnosperms
Angiosperms
What are the four phyla of gymnosperms?
Which phyla is the most biologically significant?

11. Concept 30.2: Gymnosperms bear “naked” seeds, typically on cones
The gymnosperms have “naked” seeds not enclosed by ovaries and consist of four phyla:
Cycadophyta (cycads)
Gingkophyta (one living species: Ginkgo biloba)
Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia)
Coniferophyta (conifers, such as pine, fir, and redwood)

12. Phylum Cycadophyta Individuals have large cones and palmlike leaves
These thrived during the Mesozoic, but relatively few species exist today

13. Fig. 30-5a
Figure 30.5 Gymnosperm diversity
Cycas revoluta

14. Phylum Ginkgophyta
This phylum consists of a single living species, Ginkgo biloba
It has a high tolerance to air pollution and is a popular ornamental tree

15. Ginkgo biloba pollen-producing tree
Fig. 30-5b
Figure 30.5 Gymnosperm diversity
Ginkgo biloba pollen-producing tree

16. Ginkgo biloba leaves and fleshy seeds
Fig. 30-5c
Figure 30.5 Gymnosperm diversity
Ginkgo biloba leaves and fleshy seeds

17. Phylum Gnetophyta This phylum comprises three genera
Species vary in appearance, and some are tropical whereas others live in deserts

18. Fig. 30-5e
Figure 30.5 Gymnosperm diversity
Ephedra

19. Fig. 30-5f
Figure 30.5 Gymnosperm diversity
Welwitschia

20. Fig. 30-5g
Ovulate cones
Figure 30.5 Gymnosperm diversity
Welwitschia

21. Phylum Coniferophyta
This phylum is by far the largest of the gymnosperm phyla
Most conifers are evergreens and can carry out photosynthesis year round

22. Fig. 30-5i
Figure 30.5 Gymnosperm diversity
European larch

23. Fig. 30-5j
Figure 30.5 Gymnosperm diversity
Bristlecone pine

24. Fig. 30-5k
Figure 30.5 Gymnosperm diversity
Sequoia

25. Fig. 30-5m
Figure 30.5 Gymnosperm diversity
Common juniper

26. The Life Cycle of a Pine: A Closer Look
Three key features of the gymnosperm life cycle are:
Dominance of the sporophyte generation
Development of seeds from fertilized ovules
The transfer of sperm to ovules by pollen
The life cycle of a pine provides an example
Animation: Pine Life Cycle

27. Surviving megaspore (n) Seedling
Fig
Key
Haploid (n)
Ovule
Diploid (2n)
Ovulate cone
Megasporocyte (2n)
Integument
Pollen cone
Microsporocytes (2n)
Mature sporophyte (2n)
Megasporangium (2n)
Pollen grain
Pollen grains (n)
MEIOSIS
MEIOSIS
Microsporangia
Microsporangium (2n)
Surviving megaspore (n)
Seedling
Archegonium
Figure 30.6 The life cycle of a pine
Seeds
Female gametophyte
Food reserves (n)
Sperm nucleus (n)
Seed coat (2n)
Pollen tube
Embryo (2n)
FERTILIZATION
Egg nucleus (n)

28. Angiosperms
Nonvascular plants (bryophytes)
Seedless vascular plants
Gymnosperms
Angiosperms
Angiosperms are seed plants with reproductive structures called flowers and fruits
They are the most widespread and diverse of all plants

29. Video: Flower Blooming (time lapse)
Fig. 30-7
Stigma
Carpel
Stamen
Anther
Style
Filament
Ovary
Figure 30.7 The structure of an idealized flower
Petal
Sepal
Ovule
Video: Flower Blooming (time lapse)

30. Animation: Fruit Development
Fruits
A fruit typically consists of a mature ovary but can also include other flower parts
Fruits protect seeds and aid in their dispersal
Mature fruits can be either fleshy or dry
Animation: Fruit Development

31. Tomato Ruby grapefruit Nectarine Hazelnut Milkweed Fig. 30-8
Figure 30.8 Some variations in fruit structure
Hazelnut
Milkweed

32. Wings Seeds within berries Barbs Fig. 30-9
Figure 30.9 Fruit adaptations that enhance seed dispersal
Barbs

33. The Angiosperm Life Cycle
The flower of the sporophyte is composed of both male and female structures
Male gametophytes are contained within pollen grains produced by the microsporangia of anthers
The female gametophyte, or embryo sac, develops within an ovule contained within an ovary at the base of a stigma
Most flowers have mechanisms to ensure cross-pollination between flowers from different plants of the same species

34. A pollen grain that has landed on a stigma germinates and the pollen tube of the male gametophyte grows down to the ovary
The ovule is entered by a pore called the micropyle
Double fertilization occurs when the pollen tube discharges two sperm into the female gametophyte within an ovule

35. One sperm fertilizes the egg, while the other combines with two nuclei in the central cell of the female gametophyte and initiates development of food-storing endosperm
The endosperm nourishes the developing embryo
Within a seed, the embryo consists of a root and two seed leaves called cotyledons

36. Mature flower on sporophyte plant (2n) Microsporocytes (2n)
Fig
Key
Haploid (n)
Diploid (2n)
Microsporangium
Anther
Mature flower on sporophyte plant (2n)
Microsporocytes (2n)
MEIOSIS
Generative cell
Microspore (n)
Ovule (2n)
Tube cell
Male gametophyte (in pollen grain) (n)
Ovary
Pollen grains
MEIOSIS
Germinating seed
Stigma
Megasporangium (2n)
Pollen tube
Embryo (2n) Endosperm (3n) Seed coat (2n)
Sperm
Seed
Megaspore (n)
Style
Antipodal cells Central cell Synergids Egg (n)
Figure The life cycle of an angiosperm
Female gametophyte (embryo sac)
Pollen tube
Sperm (n)
Nucleus of developing endosperm (3n)
FERTILIZATION
Zygote (2n)
Egg nucleus (n)
Discharged sperm nuclei (n)

37. Animation: Plant Fertilization
Animation: Seed Development
Video: Flowering Plant Life Cycle (time lapse)

38. Monocot Characteristics Eudicot Characteristics
Fig n
Monocot Characteristics
Eudicot Characteristics
Embryos
One cotyledon
Two cotyledons
Leaf venation
Veins usually parallel
Veins usually netlike
Figure Angiosperm diversity
Stems
Vascular tissue usually arranged in ring
Vascular tissue scattered

39. Monocot Characteristics Eudicot Characteristics
Fig o
Monocot Characteristics
Eudicot Characteristics
Roots
Root system usually fibrous (no main root)
Taproot (main root) usually present
Pollen
Pollen grain with one opening
Pollen grain with three openings
Figure Angiosperm diversity
Flowers
Floral organs usually in multiples of three
Floral organs usually in multiples of four or five

40. Basal Angiosperms
Three small lineages constitute the basal angiosperms
These include Amborella trichopoda, water lilies, and star anise

41. Fig b
Figure Angiosperm diversity
Water lily

42. Fig c
Figure Angiosperm diversity
Star anise

43. Magnoliids
Magnoliids include magnolias, laurels, and black pepper plants
Magnoliids are more closely related to monocots and eudicots than basal angiosperms

44. Fig d
Figure Angiosperm diversity
Southern magnolia

45. Monocots
More than one-quarter of angiosperm species are monocots

46. Fig e
Figure Angiosperm diversity
Orchid

47. Fig f
Figure Angiosperm diversity

48. Barley Anther Stigma Ovary Filament Fig. 30-13g
Figure Angiosperm diversity
Anther
Stigma
Ovary
Filament

49. Eudicots
More than two-thirds of angiosperm species are eudicots

50. Fig h
Figure Angiosperm diversity
California poppy

51. Fig j
Figure Angiosperm diversity
Dog rose

52. Fig l
Figure Angiosperm diversity
Zucchini flowers