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What human reproductive organ is functionally similar to this seed?

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Presentation on theme: "What human reproductive organ is functionally similar to this seed?"— Presentation transcript:

1 What human reproductive organ is functionally similar to this seed?

2 LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Plant Diversity II: The Evolution of Seed Plants Chapter 30

3 1.Why is a flower a lazy organism’s alternative to sex? 2.How do the derived characters facilitate maximizing adaptive radiation? 3.What are advantages of seeds over spores? 4.What is the purpose of double fertilization? a)What are the “quirks” in the process? Guiding questions for chapter 30

4 Five Derived Traits of Seed Plants Reduced gametophytes Heterospory Ovules Pollen Seeds Microscopic male and female gametophytes (n) are nourished and protected by the sporophyte (2n) Microspore (gives rise to a male gametophyte) Megaspore (gives rise to a female gametophyte) Ovule (gymnosperm) Integument (2n) Megaspore (n) Megasporangium (2n) Pollen grains make water unnecessary for fertilization Seeds: survive better than unprotected spores, can be transported long distances Seed coat Food supply Embryo Female gametophyte Male gametophyte REVIEW

5 Concept 30.1: Seeds and pollen grains are key adaptations for life on land the following are common to all seed plants –Seeds (an embryo with a connected food supply and a protective coat) –Reduced gametophytes –Heterospory –Ovules –Pollen © 2011 Pearson Education, Inc.

6 Figure 30.2 PLANT GROUP Mosses and other nonvascular plants Gametophyte Sporophyte (2n) Gametophyte (n) Dominant Reduced, dependent on gametophyte for nutrition Dominant Reduced, independent (photosynthetic and free-living) Ferns and other seedless vascular plants Dominant Reduced (usually microscopic), dependent on surrounding sporophyte tissue for nutrition Seed plants (gymnosperms and angiosperms) AngiospermGymnosperm Microscopic female gametophytes (n) inside these parts of flowers Microscopic female gametophytes (n) inside ovulate cone Microscopic male gametophytes (n) inside these parts of flowers Microscopic male gametophytes (n) inside pollen cone Sporophyte (2n) Sporophyte (2n) Gametophyte (n) Example

7 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 © 2011 Pearson Education, Inc.

8 Ovules and Production of Eggs An ovule consists of a megasporangium, megaspore, and one or more protective integuments –Gymnosperm megaspores have one integument –Angiosperm megaspores usually have two integuments © 2011 Pearson Education, Inc.

9 Figure Immature ovulate cone Integument (2n) Spore wall Megaspore (n) (a) Unfertilized ovule Megasporangium (2n) Pollen grain (n) Micropyle

10 Pollen and Production of Sperm Microspores develop into pollen grains, which contain the male gametophytes Pollination is the transfer of pollen to the part of a seed plant containing the ovules 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 sperm into the female gametophyte within the ovule © 2011 Pearson Education, Inc.

11 Animation: Plant Fertilization Right-click slide / select”Play”

12 © 2011 Pearson Education, Inc. Animation: Seed Development Right-click slide / select”Play”

13 Figure Immature ovulate cone Integument (2n) Spore wall Megaspore (n) Female gametophyte (n) Egg nucleus (n) Discharged sperm nucleus (n) Pollen tube Male gametophyte ( n ) (a) Unfertilized ovule Megasporangium (2n) Pollen grain (n) Micropyle (b) Fertilized ovule

14 Figure Immature ovulate cone Integument (2n) Spore wall Megaspore (n) Female gametophyte (n) Egg nucleus (n) Discharged sperm nucleus (n) Pollen tube Male gametophyte ( n ) (a) Unfertilized ovule Megasporangium (2n) Pollen grain (n) Micropyle (b) Fertilized ovule (c) Gymnosperm seed Seed coat Spore wall Food supply (n) Embryo (2n)

15 The Evolutionary Advantage of Seeds What are they? © 2011 Pearson Education, Inc.

16 Seeds provide some evolutionary advantages over spores –They may remain dormant for days to years, until conditions are favorable for germination –Seeds have a supply of stored food –They may be transported long distances by wind or animals –Protected by integuments © 2011 Pearson Education, Inc.

17 Concept 30.2: Gymnosperms bear “naked” seeds, typically on cones Gymnosperms means “naked seeds” The seeds are exposed on sporophylls that form cones Angiosperm seeds are found in fruits, which are mature ovaries © 2011 Pearson Education, Inc.

18 Figure 30.UN01 Nonvascular plants (bryophytes) Seedless vascular plants Gymnosperms Angiosperms

19 Living seed plants can be divided into two clades: gymnosperms and angiosperms –What is the ideal ecosystem for gymnosperms? © 2011 Pearson Education, Inc.

20 The gymnosperms 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) © 2011 Pearson Education, Inc.

21 Phylum Cycadophyta Individuals have large cones and palmlike leaves These thrived during the Mesozoic, but relatively few species exist today © 2011 Pearson Education, Inc.

22 Figure 30.5a Cycas revoluta Phylum Cycadophyta

23 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 © 2011 Pearson Education, Inc.

24 Ginkgo biloba leaves and fleshy seeds Ginkgo biloba pollen-producing tree Figure 30.5b

25 Phylum Gnetophyta This phylum comprises three genera Species vary in appearance, and some are tropical whereas others live in deserts © 2011 Pearson Education, Inc.

26 Figure 30.5d Ovulate cones Gnetum Ephedra Welwitschia

27 Phylum Coniferophyta This phylum is by far the largest of the gymnosperm phyla Most conifers are evergreens and can carry out photosynthesis year round © 2011 Pearson Education, Inc.

28 Figure 30.5e Douglas fir Common juniper European larch Sequoia Wollemi pine Bristlecone pine

29 © 2011 Pearson Education, Inc. Animation: Pine Life Cycle Right-click slide / select”Play”

30 Key Haploid (n) Diploid (2n) Mature sporophyte (2n) Pollen cone Microsporocytes (2n) Microsporangia Microsporangium (2n) Pollen grains (n) MEIOSIS Life cycle of a pine

31 Key Haploid (n) Diploid (2n) Mature sporophyte (2n) Ovulate cone Pollen cone Microsporocytes (2n) Microsporangia Microsporangium (2n) Surviving megaspore (n) MEIOSIS Megasporangium (2n) Pollen grain Pollen grains (n) MEIOSIS Megasporocyte (2n) Integument Ovule Figure

32 Key Haploid (n) Diploid (2n) Mature sporophyte (2n) Ovulate cone Pollen cone Microsporocytes (2n) Microsporangia Microsporangium (2n) Archegonium Surviving megaspore (n) MEIOSIS Megasporangium (2n) Pollen grain Pollen grains (n) MEIOSIS Female gametophyte Megasporocyte (2n) Integument Sperm nucleus (n) Egg nucleus (n) Pollen tube FERTILIZATION Ovule Figure

33 Key Haploid (n) Diploid (2n) Mature sporophyte (2n) Ovulate cone Pollen cone Microsporocytes (2n) Microsporangia Microsporangium (2n) Seedling Archegonium Surviving megaspore (n) MEIOSIS Megasporangium (2n) Pollen grain Pollen grains (n) MEIOSIS Female gametophyte Megasporocyte (2n) Integument Sperm nucleus (n) Egg nucleus (n) Pollen tube Seed coat (2n) FERTILIZATION Food reserves (n) Seeds Embryo (new sporophyte) (2n) Ovule Figure

34 Concept 30.3: The reproductive adaptations of angiosperms include flowers and fruits Angiosperms have two key adaptations –Flowers –Fruits –They are the most widespread and diverse of all plants © 2011 Pearson Education, Inc.

35 Why is a flower a lazy organism’s alternative to sex?

36 Stamen Anther Filament Stigma Carpel Style Ovary Petal Sepal Ovule Figure 30.7 What is the purpose of each part?

37 © 2011 Pearson Education, Inc. Video: Flower Blooming (time lapse)

38 Fruits A fruit typically consists of a mature ovary but can also include other flower parts –Fruits represent tremendous investments in a plant’s energy and nutrient resources. –What is a fruit’s purpose? Is this purpose justifiable? © 2011 Pearson Education, Inc.

39 Animation: Fruit Development Right-click slide / select”Play”

40 Tomato Ruby grapefruit Hazelnut Nectarine Milkweed Figure 30.8

41 Wings Seeds within berries Barbs Figure 30.9

42 © 2011 Pearson Education, Inc. REPEAT: Plant Fertilization Right-click slide / select”Play”

43 © 2011 Pearson Education, Inc. REPEAT : Seed Development Right-click slide / select”Play”

44 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 © 2011 Pearson Education, Inc.

45 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 triploid endosperm nourishes the developing embryo Within a seed, the embryo consists of a root and two seed leaves called cotyledons © 2011 Pearson Education, Inc.

46 Anther Mature flower on sporophyte plant (2n) Pollen grains Tube cell Generative cell Microspore (n) MEIOSIS Microsporangium Microsporocytes (2n) Key Haploid (n) Diploid (2n) Figure

47 Anther Mature flower on sporophyte plant (2n) Megasporangium (2n) Ovary Antipodal cells Central cell Synergids Female gametophyte (embryo sac) Egg (n) Surviving megaspore (n) Pollen tube Sperm (n) Pollen grains Tube cell Generative cell Microspore (n) Male gametophyte (in pollen grain) (n) Ovule (2n) MEIOSIS Microsporangium Microsporocytes (2n) Key Haploid (n) Diploid (2n) Figure

48 Anther Mature flower on sporophyte plant (2n) Megasporangium (2n) Ovary Seed Antipodal cells Central cell Synergids Female gametophyte (embryo sac) Egg (n) Egg nucleus (n) Surviving megaspore (n) Pollen tube Sperm (n) Style Sperm Pollen tube Stigma Pollen grains Tube cell Generative cell Microspore (n) Male gametophyte (in pollen grain) (n) Ovule (2n) MEIOSIS Discharged sperm nuclei (n) FERTILIZATION Microsporangium Microsporocytes (2n) Key Haploid (n) Diploid (2n) Figure

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

50 © 2011 Pearson Education, Inc. Video: Flowering Plant Life Cycle (time lapse)

51 Angiosperm Diversity Angiosperms comprise more than 250,000 living species Previously, angiosperms were divided into two main groups –Monocots (one cotyledon) –Dicots (two dicots) DNA studies suggest that monocots form a clade, but dicots are polyphyletic © 2011 Pearson Education, Inc.

52 Most recent common ancestor of all living angiosperms 300 Eudicots Monocots Magnoliids Star anise and relatives Water lilies Amborella Bennettitales Living gymnosperms Millions of years ago (b) Angiosperm phylogeny Angiosperm evolutionary history

53 The clade eudicot (“true” dicots) includes most dicots Basal angiosperms are less derived and include the flowering plants belonging to the oldest lineages Magnoliids share some traits with basal angiosperms but evolved later © 2011 Pearson Education, Inc.

54 Water lily Star anise Amborella trichopoda Basal Angiosperms Figure 30.13a

55 Magnoliids Magnoliids include magnolias, laurels, and black pepper plants Magnoliids are more closely related to monocots and eudicots than basal angiosperms © 2011 Pearson Education, Inc. Southern magnolia

56 Orchid Monocots Lily Pygmy date palm Anther Filament Stigma Ovary Barley, a grass Figure 30.13c

57 California poppy Dog rose Pyrenean oak Snow peaZucchini Eudicots (more than 2/3 of all plant species) Figure 30.13d

58 Figure 30.13e Monocot Characteristics Eudicot Characteristics Embryos One cotyledonTwo cotyledons Leaf venation Veins usually parallel Veins usually netlike Stems Vascular tissue scattered Vascular tissue usually arranged in ring Roots Root system usually fibrous (no main root) Taproot (main root) usually present Pollen Pollen grain with one opening Pollen grain with three openings Flowers Floral organs usually in multiples of three Floral organs usually in multiples of four or five

59 Evolutionary Links Between Angiosperms and Animals Animals influence the evolution of plants and vice versa –Pollinators and flowers are obviously mutualistically symbiotic –How can herbivory also be beneficial to both? © 2011 Pearson Education, Inc.

60 Video: Bat Pollinating Agave Plant

61 © 2011 Pearson Education, Inc. Video: Bee Pollinating

62 A plant pollinated by flies

63 Clades with bilateral symmetry are more diverse than those with radial symmetry?

64 Concept 30.4: Human welfare depends greatly on seed plants Most of our food comes from angiosperms Six crops (wheat, rice, maize, potatoes, cassava, and sweet potatoes) yield 80% of the calories consumed by humans Modern crops are products of relatively recent genetic change resulting from artificial selection Many seed plants provide wood Secondary compounds of seed plants are used in medicines © 2011 Pearson Education, Inc.

65 Table 30.1

66 Threats to Plant Diversity Destruction of habitat is causing extinction of many plant species In the tropics 55,000 km 2 are cleared each year At this rate, the remaining tropical forests will be eliminated in 200 years Loss of plant habitat is often accompanied by loss of the animal species that plants support © 2011 Pearson Education, Inc.

67 At the current rate of habitat loss, 50% of Earth’s species will become extinct within the next 100– 200 years The tropical rain forests may contain undiscovered medicinal compounds © 2011 Pearson Education, Inc.

68 Figure A satellite image from 2000 shows clear-cut areas in Brazil surrounded by dense tropical forest. By 2009, much more of this same tropical forest had been cut down. 4 km

69 Five Derived Traits of Seed Plants Reduced gametophytes Heterospory Ovules Pollen Seeds Microscopic male and female gametophytes (n) are nourished and protected by the sporophyte (2n) Microspore (gives rise to a male gametophyte) Megaspore (gives rise to a female gametophyte) Ovule (gymnosperm) Integument (2n) Megaspore (n) Megasporangium (2n) Pollen grains make water unnecessary for fertilization Seeds: survive better than unprotected spores, can be transported long distances Seed coat Food supply Embryo Female gametophyte Male gametophyte REVIEW

70 1.Why is a flower a lazy organism’s alternative to sex? 2.How do the derived characters facilitate maximizing adaptive radiation? 3.What are advantages of seeds over spores? 4.What is the purpose of double fertilization? a)What are the “quirks” in the process? Guiding questions for chapter 30: REVIEW


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