1 lecture #7 – angiosperm reproduction. 2 key concepts: life cycles – the alternation of...

Download 1 Lecture #7 – Angiosperm Reproduction. 2 Key Concepts: Life Cycles – the alternation of generations The structure of a flower Development of the male

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  • Slide 1
  • 1 Lecture #7 Angiosperm Reproduction
  • Slide 2
  • 2 Key Concepts: Life Cycles the alternation of generations The structure of a flower Development of the male gametophyte Pollination in all its glories Development of the female gametophyte Fertilization Embryos, seeds and fruit Asexual reproduction
  • Slide 3
  • 3 All eukaryotes cycle between a 1n and a 2n phase See F. 29.5, 7 th ed
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  • 4 Critical Thinking What is the haploid stage in animals???
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  • 5 Critical Thinking What is the haploid stage in animals???
  • Slide 6
  • 6 X Animals
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  • 7
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  • 8 All modern plants alternate between multicellular 1n and 2n generations Our focus is on the most derived group of plants the angiosperms Evolution of reproductive strategies in the other divisions will be covered in 211 See F. 29.7, 7 th ed
  • Slide 9
  • 9 Angiosperms the flowering plants By far the most important phylum of plants in the modern flora ~90% of all extant plant species Dominate most ecosystems; significant components of nearly all others 1 o ecological importance base of terrestrial food chain + many other ecosystem resources 1 o economic importance food, building materials, pharmaceuticals, horticulture, floriculture, etc, etc, etc.
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  • 10 Angiosperms the flowering plants: diverse, important AND beautiful
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  • 11 Life cycle takes place in the flower
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  • 12 ALWAYS
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  • 13 Key differences in spore fate:
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  • 14 Key differences in spore fate: What cell division process???
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  • 15 Key differences in spore fate:
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  • 16 Critical Thinking What are the functional advantages to retaining the female gametophyte???
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  • 17 Critical Thinking What are the functional advantages to retaining the female gametophyte??? What is the functional advantage of a seed???
  • Slide 18
  • 18 Critical Thinking What are the functional advantages to retaining the female gametophyte??? What is the functional advantage of a seed???
  • Slide 19
  • 19 Key differences in spore fate:
  • Slide 20
  • 20 The life cycle of angiosperms takes place in the flower: sepals petals stamens carpels Always in that order! See F. 30.7, 7 th ed
  • Slide 21
  • 21 The life cycle of angiosperms takes place in the flower: sepals petals stamens carpels Always in that order!
  • Slide 22
  • 22 ancestral paleoherbs magnoliidseudicotsmonocots Remember modern molecular evidence indicates four classes of angiosperms
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  • 23 Paleoherbs and Magnoliids comprise about 3% of angiosperms Paleoherbs Aristolochiaceae, Nymphaeaceae, etc Magnoliids Magnoliaceae, Lauraceae, nutmeg, black pepper, etc
  • Slide 24
  • 24 ancestral paleoherbs magnoliidseudicotsmonocots Modern evidence indicates 4 classes of angiosperms ~ 97% of angiosperms
  • Slide 25
  • 25 Monocots include grasses, sedges, iris, orchids, lilies, palms, etc..
  • Slide 26
  • 26 Eudicots include 70+% of all angiosperms: Most broadleaf trees and shrubs Most fruit and vegetable crops Most herbaceous flowering plants
  • Slide 27
  • 27 Monocots vs. Eudicots we talked about differences in tissue arrangement; flowers vary too Monocots Flower parts in multiples of 3 Parallel leaf venation Single cotyledon Vascular bundles in complex arrangement ~90,000 species Eudicots Flower parts in multiples of 4 or 5 Netted leaf venation Two cotyledons Vascular bundles in a ring around the stem Modern classification indicates 2 small primitive groups + eudicots 200,000+ species
  • Slide 28
  • 28 Sepals Petals Stamens Stigma (style below) A monocot flower
  • Slide 29
  • 29 Critical Thinking How do you tell sepals from petals???
  • Slide 30
  • 30 Critical Thinking How do you tell sepals from petals???
  • Slide 31
  • 31 Sepals (note point of attachment) Petals Stamens Stigma (style below) A monocot flower
  • Slide 32
  • 32 A eudicot flower Petals Stigma (style below) Stamens Sepals
  • Slide 33
  • 33 BUT for all flowers, if all parts are present they are always inserted in this order: sepals petals stamens carpels
  • Slide 34
  • 34 The base of the carpel is the ovary The ovary contains at least one ovule Dont get these 2 terms confused!
  • Slide 35
  • 35 Ovaries develop into fruits ovules develop into seeds See F. 38.9, 7 th ed
  • Slide 36
  • 36
  • Slide 37
  • 37 Angiosperm Life Cycle See F. 30.10, 7 th ed
  • Slide 38
  • 38 Development of the male gametophyte See F. 38.4, 7 th ed
  • Slide 39
  • 39 Anther sacs are the microsporangia
  • Slide 40
  • 40
  • Slide 41
  • 41 Development of the male gametophyte
  • Slide 42
  • 42 Pollen is the male gametophyte
  • Slide 43
  • 43 Pollination occurs when the pollen contacts the stigma pollen NEVER directly contacts the egg cell in the angiosperms Pollen tubes develop after pollination, elongating to eventually deliver sperm to the egg cell
  • Slide 44
  • 44 Wind Pollination: ~ 25% of all angiosperms Lots of pollen Reduced sterile structures Exserted reproductive structures Feathery and/or sticky stigma surfaces Grasses, some asters, many trees
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  • 45
  • Slide 46
  • 46 www.missouriplants.com Staminate Flowers Carpellate Flowers Acer rubrum red maple
  • Slide 47
  • 47 Animal Vectors for Pollination: ~ 75% of all angiosperms Mostly insects, but also birds, bats and other small mammals Incredible array of structural adaptations to attract pollinators: visual, scent, food, accessory structures. Many co-evolutionary relationships, especially with insects
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  • 52
  • Slide 53
  • 53 Night flying bats and moths often pollinate white flowers Alana Lea
  • Slide 54
  • 54 Critical Thinking Why would desert plants often be pollinated by night flying animals???
  • Slide 55
  • 55 Critical Thinking Why would desert plants often be pollinated by night flying animals???
  • Slide 56
  • 56
  • Slide 57
  • 57 Critical Thinking Who on earth would pollinate a flower that smells like rotten meat???
  • Slide 58
  • 58 Critical Thinking Who on earth would pollinate a flower that smells like rotten meat???
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  • 59
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  • Slide 63
  • 63 Co-evolution with the asters the Walmart strategy many small flowers open over time
  • Slide 64
  • 64 Flower, not petal Cluster of flowers
  • Slide 65
  • 65 Critical Thinking What is the selective advantage of this pattern lots of flowers, opening over time, generalist pollinators??? Are there disadvantages???
  • Slide 66
  • 66 Critical Thinking What is the selective advantage of this pattern lots of flowers, opening over time, generalist pollinators??? Are there disadvantages???
  • Slide 67
  • 67 Co-evolution with the orchids the Tiffany strategy fewer but highly specialized flowers
  • Slide 68
  • 68 Orchid Bee Bee Orchid
  • Slide 69
  • 69 Critical Thinking What is the selective advantage of this pattern highly specialized pollinators??? Are there disadvantages???
  • Slide 70
  • 70 Critical Thinking What is the selective advantage of this pattern highly specialized pollinators??? Are there disadvantages???
  • Slide 71
  • 71 Critical Thinking In both asters and orchids many seeds are produced by each floral unit Which group of seeds would have the most genetic diversity???
  • Slide 72
  • 72 Critical Thinking In both asters and orchids many seeds are produced by each floral unit Which group of seeds would have the most genetic diversity???
  • Slide 73
  • 73 Outcrossing Mechanisms Some species routinely self-fertilize (guarantees some seed production, can be less metabolically costly) Most have some mechanism to promote outcrossing so that individuals do not self pollinate.
  • Slide 74
  • 74 Critical Thinking Can you think of some mechanisms to promote outcrossing???
  • Slide 75
  • 75 Critical Thinking Can

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