Presentation is loading. Please wait.

Presentation is loading. Please wait.

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

Similar presentations


Presentation on theme: "Plant Life Cycles Plant life cycles alternate between two cycles: Producing spores and producing gametes."— Presentation transcript:

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

2 Alternation of Generations Sporophyte (diploid) –B–Begins when sperm fertilizes egg (zygote) –D–Diploid zygote divides by mitosis to create a mature sporophyte –M–Meiosis produces haploid cells called spores –H–Haploid spores released

3 Gametophyte (haploid) –B–Begins with spores created by meiosis –S–Spore grows into gametophyte Male gametophyte creates sperms Female gametophyte creates eggs –S–Sperm & egg create diploid zygote (process repeats)

4 Group One Seedless, 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 sporophyte (2n) gametophyte (1n) Capsule Spores

5 Snapshot Moss Life Cycle Snapshot Gametophyte phase –D–Dominant stage –C–Carpet of moss growing near ground Archegonium: produces female egg Antheridium: produces male sperm –S–Sperm swims through water to fertilize egg Sporophyte phase –S–Stalk grows up from the gametophyte (zygote) –S–Sporangia (capsule)houses haploid spores –S–Spores land, and new gametophyte grows See appendix B in your text book for more info

6 Gametophyte Phase 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..... Sporophyte egg male female zyg ote XX - Archegonium XY - Antheridium

7 5) Haploid spores land and grow into new gametophytes..... ground Gametophyte Phase 6) The process repeats

8 Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant Phase? MossStalk with cup (capsule) at tip, which is where spores are produced by meiosis. More familiar, carpet-like plant that produces specialized gametes. XX - Archegonium XY - Antheridium GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body (prothallus) is size of a finger nail, produces both male and female parts SPOROPHYTE ConiferMore familiar- like pine trees, produces male and female cones that produce spores Pollen grains are male gametophytes  sperm, female gameotphytes are microscopic  eggs SPOROPHYTE

9 Group Two Seedless, 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

10 Snapshot Fern Life Cycle Snapshot Sporophyte phase –D–Dominant stage –S–Sporangia (spore producing structure) creates haploid spores Sori are clusters of sporangia –S–Spores released and land Gametophyte phase –S–Spore grows into prothallus Archegonium: produces female egg Antheridium: produces male sperm –S–Sperm swims to egg –Z–Zygote begins sporophyte stage See appendix B in your text book

11 Adult Sporophyte (diploid).... 1) Sporophyte creates and releases haploid spores Ground

12 .... 2) Haploid spores land in the soil

13 Ground 3) From the haploid spores, gametophyte grows in the soil Let’s zoom in…

14 4) Sperm swim through water from the male parts (antheridium) to the female parts (archegonia) Let’s zoom back out… egg zyg ote

15 Ground 5) Diploid sporophyte grows from the zygote sporophyte

16 Ground 6) Fronds uncurls into leaves. 7) Cycle repeats -- Haploid spores created and released....

17 Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant Phase? MossStalk with cup at tip, which is where spores are produced. More familiar, carpet- like plant that produces specialized gametes XX - Archegonium XY – Antheridium GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body (prothallus) is size of a finger nail, produces both male and female parts SPOROPHYTE ConiferMore familiar- like pine trees, produces male and female cones that produce spores Pollen grains are male gametophytes  sperm, female gameotphytes are microscopic  eggs SPOROPHYTE

18 Group Three Seeded, vascular plants (ex: gymnosperms) 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 Cycad Ginkgo Conifer What are the other types of gymnosperms ?

19 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) Sporophyte stage restarts See appendix B in your text book

20 The sporophyte is the dominant phase for seed plants

21 1) Male and female seed cones grow on adult sporophytes

22 2) Pollen grains released from the male seed cones -- Pollen is the male gametophyte Let’s zoom into the female seed cone…

23 3) Pollen grain sticks to the female ovule 5) Two nuclei transfer into female spore - one fertilizes the egg 4) Pollen tube grows from the male spore 6) Diploid embryo develops (sporophyte stage restarts)

24 7) After seeds harden, the cone reopens and the seeds are released

25 8) Seed will land Ground

26 9) Seedling grows into (sporophyte)…the cycle repeats Ground

27 9) Seedling grows into (sporophyte)…the cycle repeats Ground

28 Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant Phase? MossStalk with cup at tip, which is where spores are produced. More familiar, carpet- like plant that produces specialized gametes XX - Archegonium XY - Antheridium GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body (prothallus) is size of a finger nail, produces both male and female parts SPOROPHYTE Conifer (Gymnosperm) More familiar- like pine trees, produces male and female cones that produce spores Male gametophytes are pollen grains  sperm Female gametophytes are microscopic  eggs SPOROPHYTE

29 Group Four Seeded, vascular plants (ex: angiosperm)

30 carpel style stigma ovary stamen filamentanther petal sepal Sepals and petals are modified leaves. Sepals are outermost layer that protects developing 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

31 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

32 Fertilization takes place within the flower Male gametophytes, or pollen grains, are produced in the anthers. –Male spores produced in anthers by meiosis –Each spore divides by mitosis to form two haploid cells –Two cells form a single pollen grain Pollen grain Anther Stamen Filament

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

34 1. Pollen stick to animal or released into wind.

35

36 .. 3. Pollen tube grows and 2 nuclei transfer into the ovule Let’s zoom in… 2. Animal finds a new flower to feed on and pollen grains land on the stigma (pollination)

37 4. Flowering plants go through the process of double fertilization. female gametophyte ovule egg sperm polar nuclei 1 sperm fuse with the polar nuclei = triploid (3n) endosperm 1 sperm fuse with the egg = zygote Double Fertilization

38 endosperm seed coat embryo Endosperm provides food supply for embryo 5. Each ovule becomes a seed. The surrounding ovary grows into a fruit.

39 6. Seeds get dispersed 7. Seed germinates, and the cycle starts over Ground

40 Plant Life Cycle Comparisons Plant typeSporophyteGametophyteDominant Phase? MossStalk with cup at tip, which is where spores are produced. More familiar, carpet-like plant that produces specialized gametes XX - Archegonium XY - Antheridium GAMETOPHYTE FernMore familiar, leafy plant with clusters of spore producing sacs (sori) Haploid plant body is size of a finger nail, produces both male and female parts SPOROPHYTE Conifer (Gymnosperm) More familiar - like pine trees, produces male and female cones that produce spores Male gametophytes are pollen grains  sperm Female gametophytes are microscopic  eggs SPOROPHYTE Flowers (Angiosperm) More familiar - apple tree, peach tree, zucchini, berries, etc. Contain flowers that produce male and female spores Pollen grains are male gametophytes  2 haploid cells = pollen tube + sperm Female gametophyte in ovule  egg + 2 polar nuclei SPOROPHYTE


Download ppt "Plant Life Cycles Plant life cycles alternate between two cycles: Producing spores and producing gametes."

Similar presentations


Ads by Google