1. Plant Evolution & Diversity – Ch. 22-25

2. Kingdom Protista: Algae & Protozoa
Simple Eukaryotes – mostly single-celled
Organisms in this Kingdom don’t fit clearly into what we call plant, animal, or fungi.
Most diverse eukaryotic Kingdom (>60,000 species).
We are interested in this Kingdom because of the Chlorophytes & Charophyceans - green algae.

3. The line between Kingdom Protista and Kingdom Plantae is still being discussed……

4. Characteristics of Green Algae - Chlorophytes.
Can live symbiotically with fungi as lichens

5. Fig 28.30
Volvox - freshwater
Ulva – sea lettuce
Caulerpa - intertidal

6. Characteristics of Green Algae - Charophyceans
500 million years ago, the algal ancestors of plants formed a green carpet on the edge of lakes and coastal salt marshes

7. Coleochaete, a simple charophyte.
Figure 17.1A Coleochaete, a simple charophyte.
Coleochaete, a simple charophyte.

8. Chara, an elaborate charophyte.
Figure 17.1B Chara, an elaborate charophyte.

9. Plants
Plants are..
So how are they different from Charophyceans??

10. What challenges did plants face when they “moved” onto land?

11. Adaptation to life on Land – All plants have:
Apical Meristems
Alternation of generations life cycle

12. 1. Apical Meristems –

13. 2. Alternation of Generations

14. 2 multicellular life stages:
Sporophyte:
Spores – haploid cells that can grow into a new, multicellular, haploid organism (the gametophyte) without fusing to another cell.
Gametophyte:
Egg & sperm fuse to form the diploid zygote, which divides by mitosis to form the sporophyte

15. Spores produced in sporangia
sporangia divide by meiosis to form the haploid spores

16. sporocytes

17. Gametangia =
2 types of gametangia:
Archegonia – produce eggs
Antheridia – produce sperm
Sperm travel to the egg, fertilizing it within the archegonia.

19. Other examples of adaptations to life on land: (not all plants have the following):
Cuticle –
Secondary compounds –
Roots - absorb water and minerals from the soil
Shoots - stems and leaves to make food.
Stomata – openings in the leaf surface to allow gas exchange for photosynthesis and to regulate water loss.

20. More Adaptations
4. .
5. A vascular system that transports food & water from roots to shoots and vice versa.

23. Stomata; roots anchor plants, absorb water; lignified cell
Key
Vascular
tissue
Leaf
Spores
Spores
Flagellated
sperm
Alga
Water supports
alga. Whole alga
performs photo-
synthesis;
absorbs water,
CO2, and
minerals from
water.
Flagellated
sperm
Leaf
Stem
Stem
Roots
Fern
Stomata; roots anchor plants,
absorb water; lignified cell
walls; vascular tissue;
fertilization requires moisture
Roots
Figure 17.1C Comparing the terrestrial adaptations of moss, fern, and pine with Chara, a multicellular green.
Moss
Stomata only on sporophytes;
primitive roots anchor plants,
no lignin; no vascular tissue;
fertilization requires moisture
Flagellated
sperm
Holdfast
(anchors alga)

24. roots anchor plants, absorb water;
Key
Vascular
tissue
Pollen
Seed
Leaf
Stem
Figure 17.1C Comparing the terrestrial adaptations of moss, fern, and pine with Chara, a multicellular green.
Roots
Pine tree
Stomata;
roots anchor plants, absorb water;
lignified cell walls; vascular tissue;
fertilization does not require moisture

25. Earliest group: Nonvascular Land Plants
Earliest land plants
3 Groups:
liverworts
hornworts
mosses .
Peat moss (sphagnum): doesn’t decay rapidly, stores 400 bil tons of carbon
Gametophyte is the dominant generation:

26. liverworts

27. hornworts

28. Mosses

29. Gametophytes make up a bed of moss
Moss life cycle
Gametophytes make up a bed of moss
The zygote develops within the gametangium into a mature sporophyte, which remains attached to the gametophyte
Meiosis occurs in sporangia at the tips of the sporophyte stalk
Haploid spores are released from the sporangium and develop into gametophytes
Student Misconceptions and Concerns
1. Students can easily confuse the animal and plant reproductive cycles. However, the unique feature of alternation of generations in plants (and certain algae) makes analogies and parallels challenging and potentially confusing when referencing animal life cycles. One possible relevant exercise would be to compare the timing of mitosis and meiosis in plant and animal life cycles.
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. Students might wonder if humans and other animals do not also qualify as having alternation of generations. Although we do have haploid gametes, the haploid and diploid stages do not include multicellular individuals.
Copyright © 2009 Pearson Education, Inc.

30. Gametophytes (n) Key Haploid (n) Male Diploid (2n) Mitosis and1
Haploid (n)
Diploid (2n)
Male
Mitosis and
development 5
Sperm (n)
Female
gametangium
Spores (n)
Female
Egg (n) 1
Fertilization
Sporangium
Stalk
Figure 17.4 Life cycle of a moss.
Meiosis 2
Sporophyte (2n)
Zygote (2n) 4 3
Mitosis
and development

31. Step 1: Moss gametophyte (n)

32. Step 2: Within the gametophyte, archegonia make eggs
and antheridia make sperm, by mitosis:
Archegonia
egg
Sac full of sperm

34. Step 3: Sperm swims to the egg fertilization (create of a 2n zygote)

35. Step 4: mature sporophyte capsules release spores…
Step 4: mature sporophyte capsules release spores….which grow into new gametophytes

36. Peat bogs –

37. Vascular Plants Vascular tissue: Xylem = Phloem =
Dominant generation = sporophyte

38. Fern gametophytes are small and inconspicuous
Fern life cycle
Fern gametophytes are small and inconspicuous
The zygote initially develops within the female gametangia but eventually develops into an independent sporophyte
Sporangia develop on the underside of the leaves of the sporophyte
Within the sporangia, cells undergo meiosis to produce haploid spores
Spores are released and develop into gametophytes
Student Misconceptions and Concerns
1. Students can easily confuse the animal and plant reproductive cycles. However, the unique feature of alternation of generations in plants (and certain algae) makes analogies and parallels challenging and potentially confusing when referencing animal life cycles. One possible relevant exercise would be to compare the timing of mitosis and meiosis in plant and animal life cycles.
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. Students might wonder if humans and other animals do not also qualify as having alternation of generations. Although we do have haploid gametes, the haploid and diploid stages do not include multicellular individuals.
For the BLAST Animation Non-Flowering Plant Life Cycle, go to Animation and Video Files.
Copyright © 2009 Pearson Education, Inc.

39. Two major groups of seedless vascular plants:
Lycophytes .
were tree-like in the Carboniferous period
3 kinds: club mosses, spike mosses, and quillworts

40. Club moss
Figure 17.2C Seedless vascular plants: club moss.

41. Spike moss

42. Quillwort

43. 2. Pterophytes – 3 kinds
Whisk ferns –
Horsetails –
Ferns – produce clusters (sori) of sporangia on underside of leaves (fronds)

44. Whisk fern

45. Horsetails

46. Ferns
Figure 17.2C Seedless vascular plants: fern.

47. Key Haploid (n) Diploid (2n) Sperm (n) Mitosis and development Female1
Haploid (n)
Diploid (2n)
Sperm (n) 5
Mitosis and
development
Female
gametangium (n)
Gametophyte (n)
Spores (n)
Egg (n)
Meiosis
Fertilization
Clusters of
sporangia 4 2
Zygote (2n)
Figure 17.5 Life cycle of a fern.
New sporophyte (2n) 3
Mitosis and
development
Mature sporophyte

48. Forests of the Carboniferous period (290-360 mil years ago):
Swampy forests – slow decay in low O2, formed deep layers of organic matter
Heat + pressure + time ----> coal
Pulled lots of CO2 out of atmosphere, cooling the earth & forming glaciers
Larger species died out when climate became drier

49. Terrestrial Adaptations of Seed Plants
Seeds replace spores as main means of dispersal.
Why?
Gametophytes became reduced and retained within the sporophyte
Pollen & Pollination - freed plants from the requirement of water for fertilization.

50. 1. Seeds replace spores as main means of dispersal.
old way (ferns & mosses) = spores released from sporangia to disperse and develop into gametophytes
new way:
ovule = female sporangium + female spore. Female gametophyte develops within the spore & produces eggs.
after fertilization, the ovule becomes the seed
seed = sporophyte embryo + food supply (mature ovule tissues)

52. 2. Reduction of the gametophyte:

53. 3. Pollen & Pollination Pollen = Pollination =
Pollen tube brings sperm to egg within the ovule

54. Two types of seed plants: 1. Gymnosperms
2. Angiosperms
flowering plants
Most diverse
Evolved from gymnosperms:

55. Gymnosperms Four major groups Ginko biloba Cycads (look like palms)
Gnetophytes
Conifers – cone-bearing trees .
Needle-shaped leaves to reduce water loss during drought

56. Cycads
Figure 17.2D Gymnosperms: Cycad.

57. Ginko biloba

58. Gnetophytes
Figure 17.2D Gymnosperms: Ephedra.
Ephedra

59. Welwitschia

60. Conifers
Figure 17.2D Gymnosperms: blue spruce.

61. Bristlecone pine
oldest

62. Tallest

63. Pine life cycle
A pine cone holds all of the tree’s reproductive stages: spores, eggs, sperm, zygotes, and embryos
The male gametophyte is a pollen grain, released from pollen cones and carried by wind to female cones
Female ovulate cones carry two ovules on each stiff scale - Each ovule contains a sporangium
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. As the authors note, much time can pass between pollination, fertilization, and the production of seeds in pine trees. This entire process may take two years. This lengthy period of time, the alternation of generations, and other specific details of the gymnosperm life cycle can create confusion. Students with little experience in plant biology may need considerable support in fitting all of these details into the life cycle.
Copyright © 2009 Pearson Education, Inc.

64. spores; spores develop into pollen grains. Scale A haploid spore cell 1
Sporangia produce
spores; spores develop
into pollen grains.
Scale 4
A haploid spore cell
develops into female
gametophyte, which
makes eggs.
Sporangium (2n) 5
Pollen grows
tube to egg
and makes
and releases
sperm.
Ovule
Meiosis
Meiosis
Spore mother cell (2n)
Integument 3
Pollination
Pollen grains
(male gameto-
phytes) (n)
Egg (n)
Fertilization
Sperm (n)
Female
gametophyte (n)
Male gametophyte
(pollen grain) 2
Ovulate cone
bears ovules.
Zygote
(2n)
Mature sporophyte
Figure 17.7 Life cycle of a pine tree.
Seed coat
Seed
Embryo (2n)
Food supply
Key 6
Zygote develops
into embryo, and
ovule becomes seed.
Haploid (n)
Diploid (2n) 7
Seed germinates,
and embryo grows into seedling.

65. In pollination, a pollen grain lands on a scale in an ovulate cone and enters an ovule
Fertilization occurs a year after pollination, when a sperm moves down a pollen tube to the egg to form a zygote
The zygote develops into a sporophyte embryo, and the ovule becomes a seed, with stored food and a protective seed coat
The seed is a key adaptation for life on land and a major factor in the success of seed plants
To help students understand the complex and very modified life cycles of seed plants, emphasize homology with the stages and structures in the fern life cycle.
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. As the authors note, much time can pass between pollination, fertilization, and the production of seeds in pine trees. This entire process may take two years. This lengthy period of time, the alternation of generations, and other specific details of the gymnosperm life cycle can create confusion. Students with little experience in plant biology may need considerable support in fitting all of these details into the life cycle.
Copyright © 2009 Pearson Education, Inc.

66. Angiosperms
Difference from gymnosperms?
Seeds are enclosed in the moist reproductive tissue called the ovary….which becomes the fruit
More insects and animals for pollination, less dependent on wind.
2 major groups
Monocots
Dicots

68. The flower is the centerpiece of angiosperm reproduction
Flowers contain separate male and female sporangia and gametophytes
Flowers usually consist of sepals, petals, stamens (which produce pollen), and carpels (which produce eggs)
Stamens include a filament and anther, a sac at the top of each filament that contains male sporangia and releases pollen
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. As Francois Jacob suggested, evolution works as a tinkerer and not like an engineer. New forms evolve by remodeling old forms. The structure of a flower represents the remodeling of leaves, a subject that you may want to explore in additional detail as an important lesson in evolution.
3. Floral shops frequently discard magnificent flowers that are just beyond their peak. Teachers can obtain such discards for free by contacting local floral shops and sharing their educational needs. Having a variety of flowers on hand can brighten up any discussion of angiosperms.
Copyright © 2009 Pearson Education, Inc.

70. Evolutionary success of Angiosperms due to:
Increased water transport efficiency due to improvement in xylem tissue:
Flowers – attract pollinators
Fruits – many forms for variety of dispersal mechanisms

71. Haploid spores in anthers develop into 1
Haploid spores in anthers develop into
pollen grains: male gametophytes.
Pollen grains (n) 3
Pollination and
growth of
pollen tube
Meiosis
Stigma 2
Haploid spore in each ovule
develops into female gameto-
phyte, which produces an egg.
Pollen grain
Stigma
Pollen tube
Anther
Meiosis
Egg (n)
Ovule
Ovary
Sporophyte (2n)
Ovule
Sperm 7
Seed germinates,
and embryo
grows into
plant.
Seeds
Figure 17.9 Life cycle of an angiosperm. 6
Fruit
(mature
ovary)
Food supply
Fertilization
Seed
coat
Key
Haploid (n)
Diploid (2n) 5
Seed 4
Zygote
(2n)
Embryo (2n)

72. The structure of a fruit reflects its function in seed dispersal
Fruits, ripened ovaries of flowers, are adaptations that disperse seeds .
Fleshy, edible fruits attract animals
Point out that the seeds from edible fruit are deposited with a supply as natural fertilizer, while the animal gets a meal. Not all animals benefit from their role as seed dispersers, as the dog with the cockleburs shows.
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. Before lecturing on the examples of angiosperm and animal cooperation, let your students try to name as many as they can. They may be assigned to do so as an in class activity in small groups, or they may compile lists individually that can be brought into class or ed to the instructor.
3. The symbiotic relationships between angiosperms and animals are extensive. Challenge students to list all of the ways that plant reproduction benefits from animals (examples include the role of nectar in attracting pollinators, seed dispersal in fruit, and hitchhiker strategies such as that revealed in Figure 17.10B). Not all animals benefit from these relationships.
Copyright © 2009 Pearson Education, Inc.

73. Angiosperms sustain us—and add spice to our diets
Most human food is provided by the fruits and seeds of angiosperms
Spices such as nutmeg, cinnamon, cumin, cloves, ginger, and licorice are also angiosperm fruits
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. Before lecturing on the examples of angiosperm and animal cooperation, let your students try to name as many as they can. They may be assigned to do so as an in class activity in small groups, or they may compile lists individually that can be brought into class or ed to the instructor.
3. The symbiotic relationships between angiosperms and animals are extensive. Challenge students to list all of the ways that plant reproduction benefits from animals (examples include the role of nectar in attracting pollinators, seed dispersal in fruit, and hitchhiker strategies such as that revealed in Figure 17.10B). Not all animals benefit from these relationships.
4. You might have your class spend a minute just listing the plant-derived materials in your classroom. These will include cotton cloth, wood for pencils, paper in many forms, etc. In addition, have students try to imagine how they could spend an entire day without encountering plants or plant products.
Copyright © 2009 Pearson Education, Inc.

74. Pollination by animals has influenced angiosperm evolution
90% of angiosperms use animals to transfer pollen
Bats are attracted by large, highly scented flowers
Wind-pollinated flowers produce large amounts of pollen
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. Before lecturing on the examples of angiosperm and animal cooperation, let your students try to name as many as they can. They may be assigned to do so as an in class activity in small groups, or they may compile lists individually that can be brought into class or ed to the instructor.
3. The symbiotic relationships between angiosperms and animals are extensive. Challenge students to list all of the ways that plant reproduction benefits from animals (examples include the role of nectar in attracting pollinators, seed dispersal in fruit, and hitchhiker strategies such as that revealed in Figure 17.10B). Not all animals benefit from these relationships.
4. You might have your class spend a minute just listing the plant-derived materials in your classroom. These will include cotton cloth, wood for pencils, paper in many forms, etc. In addition, have students try to imagine how they could spend an entire day without encountering plants or plant products.
5. The tremendous volume of pollen released into the air is apparent to anyone suffering from allergies. You might wish to have your students find the pollen counts for your area, which is commonly provided as part of weather reports. It might be interesting to track the pollen counts as you go through the semester.
Copyright © 2009 Pearson Education, Inc.

75. Plant diversity is an irreplaceable resource
More than 50,000 square miles of forest are cleared every year
Replanted areas have greatly reduced biological diversity
Loss of forests has greatly reduced diversity of life on Earth
The loss of plant diversity removes potentially beneficial medicines
More than 25% of prescription drugs are extracted from plants
Teaching Tips
1. The authors describe four key adaptations for life on land in Module The following modules (17.3–17.13) describe how these adaptations distinguish the main lineages of the plant kingdom. This is consistent with good lecture advice: Tell them what you are going to tell them, tell them, then tell them what you told them (summarize).
2. Before lecturing on the examples of angiosperm and animal cooperation, let your students try to name as many as they can. They may be assigned to do so as an inclass activity in small groups, or they may compile lists individually that can be brought into class or ed to the instructor.
3. You might have your class spend a minute just listing the plant-derived materials in your classroom. These will include cotton cloth, wood for pencils, paper in many forms, etc. In addition, have students try to imagine how they could spend an entire day without encountering plants or plant products.
4. Referencing local examples of monoculture replacing a more diverse native ecosystem can help reinforce the content of Module Encouraging students to look around your community and note where old-growth forest has been replaced with a single fast-growing species, or where native prairies have given way to vast fields of corn, wheat, or soybeans, will bring home the loss of plant diversity as modeled in their own backyard.
Copyright © 2009 Pearson Education, Inc.

76. Table 17.13 A Sampling of Medicines Derived from Plants.

77. Ch. 9: flowers, fruits: Angiosperm Reproduction

78. Fig 30.3

79. Notice the triploid stage!
Double fertilization – one sperm unites with the egg to form the 2n zygote, other sperm unites with the two nuclei of the female gametophyte to form a 3n endosperm – becomes food for the developing embryo
Ovule matures into the seed – contains sporophyte embryo & endosperm (food).
Ovary (female sporangium tissues) matures into the fruit.

80. The Angiosperm Life Cycle
Male gametophyte =
Female gametophyte = embryo sac, develops in the ovule of the ovary. Produces egg

81. Development of Male Gametophyte (Pollen)
Anther is composed of pollen sacs (sporangium).
Inside pollen sac: diploid cells undergo meiosis to form 4 haploid microspores.
Each microspore divides by mitosis to make 2 cells:
Generative cell –
Tube cell –
The 2 cells enclosed in thick wall => pollen grain

82. Development of the Female Gametophyte (Embryo Sac)
Ovule = female sporangium
Only one megaspore survives and divides by mitosis 3 times to make 8 haploid nuclei.

83. Embryo Sac = female gametophyte
Antipodal cells
2 polar nuclei
Egg
Synergid cells

84. Fig 38.4

85. Angiosperm Reproduction
Pollen grain lands on stigma (= pollination)
Generative cell divides by mitosis to form 2 sperm cells
Tube cell forms pollen tube
Sperm travel down pollen tube and enter embryo sac
Double fertilization –
Egg + sperm  zygote
2 polar nuclei + sperm  3n nucleus that becomes the endosperm

86. Double fertilization

87. Maturation
Embryo divides to form cotyledons (= seed leaves) and meristems
Ovule is now a seed – dehydrates & becomes dormant (low metabolism, no growth).
Ovary tissues divide & mature into fruit