Lecture 9 Outline (Ch. 38) - PowerPoint PPT Presentation

1 / 31
About This Presentation
Title:

Lecture 9 Outline (Ch. 38)

Description:

... asexual propagation of angiosperms Cuttings can be taken from many kinds of plants They are asexually reproduced from plant fragments Grafting is a ... – PowerPoint PPT presentation

Number of Views:209
Avg rating:3.0/5.0
Slides: 32
Provided by: Bry51
Category:

less

Transcript and Presenter's Notes

Title: Lecture 9 Outline (Ch. 38)


1
(No Transcript)
2
Lecture 9 Outline (Ch. 38)
  • I. Flower Structures
  • II. Life cycle
  • III. Gametophyte production Dispersal
  • Pollination
  • Fertilization
  • Germination
  • VII. Lecture Concepts

3
Angiosperm Overview
4
Angiosperm Overview
  • In alternation of generations in angiosperms, the
    dominant stage is the diploid
  • sporophyte
  • Spores develop inside the flower into tiny,
    haploid gametophytes
  • the male pollen grain and the female embryo sac
    (Figure 38.3)

5
Angiosperm Lifecycle
6
Angiosperm Gametophytes
  • Develop with anthers and ovaries, respectively
  • Pollen develops from microspores inside the
    sporangia of the anther
  • Within an ovule, a haploid megaspore divides by
    mitosis and forms the embryo sac, the female
    gametophyte

7
Angiosperm Gametophytes
Figure 38.3
8
Angiosperm Pollination
  • brings female and male gametophytes together
  • Fertilization (syngamy) is preceded by
    pollination, the placing of pollen on the stigma
    of the carpel

9
Abiotic Pollination by Wind
Hazel staminate flowers (stamens only)
Hazel carpellate flower (carpels only)
10
Pollination by Bees
Common dandelion under normal light
Common dandelion under ultraviolet light
11
Pollination by Moths and Butterflies
Anther
Stigma
Moth on yucca flower
12
Pollination by Flies
Fly egg
Blowfly on carrion flower
13
Pollination by Birds
Hummingbird drinking nectar of poro flower
14
Pollination by Bats
Long-nosed bat feeding on cactus flower at night
15
Angiosperm Pollination
  • The pollen grain produces a pollen tube that
    extends down the style toward the embryo sac
  • Two sperm are released and effect a double
    fertilization, resulting in a diploid zygote and
    a triploid (3n) endosperm (Figure 38.5)

16
Angiosperm Fertilization
17
Angiosperm Seed Formation
  • develops into a seed containing a sporophyte
    embryo and a supply of nutrients (Figure 38.7)
  • The zygote gives rise to an embryo with apical
    meristems and one or two cotyledons
  • Mitosis of the triploid (3n) endosperm gives rise
    to a multicellular, nutrient-rich mass that feeds
    the developing embryo and later (in some plants)
    the young seedling

18
Angiosperm Seed Formation
19
The Ovary ...
  • develops into a fruit adapted for seed dispersal
  • a fruit is a mature ovary that protects the
    enclosed seeds and aids in their dispersal via
    wind, water, or animals

20
Dispersal by Water
Coconut
21
Dispersal by Wind
Winged seed of Asian climbing gourd
Dandelion parachute
Winged fruit of maple
Tumbleweed
22
(No Transcript)
23
The Mature Seed
  • The embryo and its food supply are enclosed by a
    hard, protective seed coat
  • The seed enters a state of dormancy
  • In some eudicots, such as the common garden bean,
    the embryo consists of the embryonic axis
    attached to two thick cotyledons (seed leaves)
  • A monocot embryo has one cotyledon

24
Angiosperm Seeds
25
Evolutionary Adaptations ...
  • the process of germination increases the
    probability that seedlings will survive
  • Germination begins when seeds imbibe water
  • this expands the seed, rupturing its coat, and
    triggers metabolic changes that cause the embryo
    to resume growth
  • The embryonic root, or radicle, is the first
    structure to emerge from the germinating seed
  • Next, the embryonic shoot breaks through the soil
    surface (Figure 38.9)

26
Seed Germination (bean)
(a) Common garden bean
Foliage leaves
Cotyledon
Epicotyl
Hypocotyl

Cotyledon
Cotyledon
Hypocotyl
Hypocotyl
Radicle
Seed coat
27
Many Plants Can ...
  • clone themselves by asexual reproduction
  • Asexual reproduction (cloning) is the
    reproduction of genetically identical offspring
    from a single parent
  • Apomixis
  • production of seeds without fertilization

28
Vegetative Reproduction Agriculture
  • Humans have devised various methods for asexual
    propagation of angiosperms
  • Cuttings can be taken from many kinds of plants
  • They are asexually reproduced from plant
    fragments
  • Grafting is a modification of vegetative
    reproduction from cuttings
  • A twig or bud from one plant can be grafted onto
    a plant of a closely related species or a
    different variety of the same species

29
Vegetative Reproduction Agriculture
  • Maize
  • Is a product of artificial selection by humans
  • Is a staple in many developing countries, but is
    a poor source of protein

30
Self-Check
Part of plant Function Later becomes Examples
Ovary Contains eggs (ovules) Flesh of fruit Apples, strawberries, coconut meat
Pollen
Ovule
Integuments
Cotyledons
Endosperm
31
Lecture 9 concepts
  • Describe the parts of a flower. Define
    angiosperms.
  • Explain the process that plants use for
    generating pollen and eggs/ovules.
  • Contrast pollination and fertilization.
  • Discuss several types of pollination
    methods/pollinators.
  • Diagram/explain what each part of the fertilized
    ovule, coverings, and ovary becomes.
  • What is the purpose of a fruit? Describe
    methods of seed dispersal.
  • Compare monocot and dicot seeds.
  • List the steps of germination. How do seeds know
    when to germinate?
  • How have humans changed the way plants develop?
    (many answers)
  • Write out a list of new terminology and provide
    descriptions
Write a Comment
User Comments (0)
About PowerShow.com