slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Plant Life Cycles PowerPoint Presentation
Download Presentation
Plant Life Cycles

Loading in 2 Seconds...

play fullscreen
1 / 40

Plant Life Cycles - PowerPoint PPT Presentation


  • 118 Views
  • Uploaded on

Plant Life Cycles. Plant life cycles alternate between two cycles: Producing spores and producing gametes. Alternation of Generations. Sporophyte (diploid) Begins when sperm fertilizes egg (zygote) Diploid zygote divides by mitosis to create a mature sporophyte

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Plant Life Cycles' - les


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Plant Life Cycles

Plant life cycles alternate between two cycles: Producing spores and producing gametes

alternation of generations
Alternation of Generations
  • Sporophyte (diploid)
    • Begins when sperm fertilizes egg (zygote)
    • Diploid zygote divides by mitosis to create a mature sporophyte
    • Meiosis produces haploid cells called spores
    • Haploid spores released
alternation of generations1
Alternation of Generations
  • Gametophyte (haploid)
    • Begins with spores created by meiosis
    • Spore grows into gametophyte
      • Male gametophyte creates sperms
      • Female gametophyte creates eggs
    • Sperm & egg create diploid zygote (process repeats)
group one seedless nonvascular plants ex moss

Capsule

Spores

sporophyte (2n)

gametophyte (1n)

Group OneSeedless, nonvascular plants (ex: moss)
  • Characteristics:
    • Live in moist environments
    • Lack true leaves (only one cell thick)
    • Rhizoids anchor into soil
    • Early inhabitant of new ecosystems (succession)
    • Moss gametophytes look like green carpet
    • Moss sporophytes shoot up as stalk-like structures
moss life cycle snapshot
Moss Life Cycle Snapshot
  • Gametophyte phase
    • Dominant stage
    • Carpet of moss growing near ground
      • Archegonium: produces female egg
      • Antheridium: produces male sperm
    • Sperm swims through water to fertilize egg
  • Sporophyte phase
    • Stalk grows up from the gametophyte (zygote)
    • Sporangia (capsule)houses haploid spores
    • Spores land, and new gametophyte grows

See appendix B in your text book for more info

slide6

1) Moss gametophytes grow near the ground (haploid stage)

2) Through water, sperm from the male gametophyte will swim to the female gametophyte to create a diploid zygote

3) Diploid sporophyte will grow from zygote

4) Sporophyte will create and release haploid spores

.

.

.

.

.

XY - Antheridium

Sporophyte

XX - Archegonium

egg

zygote

zygote

egg

egg

zygote

zygote

egg

male

male

Gametophyte Phase

female

female

female

male

female

male

slide7

5) Haploid spores land and grow into new gametophytes

6) The process repeats

.

.

.

.

.

ground

Gametophyte Phase

group two seedless vascular plants ex ferns
Group TwoSeedless, vascular plants (ex: ferns)
  • Characteristics:
    • Vascular system allows nutrient transport to greater heights
    • Rhizoids: Underground stems draw nutrients, like roots
    • Fiddleheads are uncurled leaves (fronds)
    • Fern sporophytes are the typical leaf like plant
    • Fern gametophytes (prothallus) look like a heart
fern life cycle snapshot
Fern Life Cycle Snapshot
  • Sporophyte phase
    • Dominant stage
    • Sporangia (spore producing structure) creates haploid spores
      • Sori are clusters of sporangia
    • Spores released and land
  • Gametophyte phase
    • Spore grows into prothallus
      • Archegonium: produces female egg
      • Antheridium: produces male sperm
    • Sperm swims to egg
    • Zygote begins sporophyte stage

See appendix B in your text book

slide11

1) Sporophyte creates and releases haploid spores

.

.

.

.

Adult

Sporophyte (diploid)

Ground

slide14

4) Sperm swim through water from the male parts (antheridium) to the female parts (archegonia)

Let’s zoom back out…

egg

zygote

egg

zygote

egg

zygote

slide16

6) Fronds uncurls into leaves.

7) Cycle repeats

-- Haploid spores created and released

.

.

.

.

Ground

group three seeded vascular plants ex gymnosperms
Group ThreeSeeded, vascular plants (ex: gymnosperms)

Cycad

Ginkgo

  • Characteristics:
    • Vascular system allows nutrient transport to greater heights
    • Seeds not enclosed in fruit (angiosperms); produced inside cones
      • Advantages of seed plants
        • Seeds allow for reproduction without free-standing water = Pollen
        • Seeds nourish and protect the growing plant embryo = Endosperm , seed coat, dormancy
        • Seeds allow plants to disperse to new places = Wind, water, animals
    • Conifer sporophyte is the typical tree like structure
    • Conifer gametophytes are inside the male/female cones

Conifer

What are the other types of gymnosperms?

conifer life cycle snapshot
Conifer Life Cycle Snapshot
  • Sporophyte phase
    • Dominant stage
    • Cones grow on tree
      • Female cones produce egg & seed
      • Male cones produce pollen
    • Pollen reaches end of female scale and sticks to ovule
      • Pollen tube grows from pollen
      • Sperm travels down pollen tube (zygote/seed created)
      • Sporophytestage restarts

See appendix B in your text book

slide22

2) Pollen grains released from the male seed cones -- Pollen is the male gametophyte

Let’s zoom into the female seed cone…

slide23

3) Pollen grain sticks to the female ovule

4) Pollen tube grows from the male spore

5) Two nuclei transfer into female spore - one fertilizes the egg

6) Diploid embryo develops (sporophyte stage restarts)

flowers contain reproductive organs protected by specialized leaves

stamen

filament

anther

stigma

style

carpel

ovary

sepal

petal

Flowers contain reproductive organs protected by specialized leaves
  • Sepals and petals are modified leaves.
    • Sepals are outermost layer that protectsdeveloping flower
    • Petals can help to attract animal pollinators
    • A stamen is the male structure of the flower
      • anther produces pollen grains
      • filament supports the anther
      • The innermost layer of a flower is the female carpel.
        • stigma is sticky tip
        • style is tube leading from stigma to ovary
        • ovary produces female gametophyte
flowering plants can be pollinated by wind or animals
Flowering plants can be pollinated by wind or animals
  • Wind pollinated flowers have small flowers and large amounts of pollen.
  • Animal pollinated flowers have larger flowers and less pollen.

many flowering plants pollinated by animal pollinators

    • Pollination occurs as animal feeds from flower to flower
    • Animal pollination more efficient than wind pollination
fertilization takes place within the flower
Fertilization takes place within the flower
  • Male gametophytes, or pollen grains, are produced in the anthers.
    • Male spores produced inanthers by meiosis
    • Each spore divides bymitosis to form twohaploid cells
      • Two cells form asingle pollen grain

Pollen grain

Stamen

Anther

Filament

slide33

One female gametophyte can form in each ovule of a flower’s ovary

  • Many cells can be made in the ovule
    • One cell becomes the egg
    • One cell becomes 2 polar nuclei
      • The rest die

Polar nuclei (2n)

slide36

2. Animal finds a new flower to feed on and pollen grains land on the stigma (pollination)

3. Pollen tube grows and 2 nuclei transfer into the ovule

.

.

Let’s zoom in…

slide37

female

gametophyte

egg

sperm

polar nuclei

ovule

4. Flowering plants go through the process of double fertilization.

Double Fertilization

1 sperm fuse with the polar nuclei = triploid (3n) endosperm

1 sperm fuse with the egg = zygote

slide38

endosperm

seed coat

embryo

5. Each ovule becomes a seed.

  • Endosperm provides food supply for embryo

The surrounding ovary grows into a fruit.

slide39
6. Seeds get dispersed

7. Seed germinates, and the cycle starts over

Ground