1. Plant Life Cycles

2. Plant Evolution Descendants from green algae (~450mya)
Contain cellulose in cell walls
Contain chlorophyll
Starch stored
Land Plants Must Overcome
Drying out
Gas exchange
Nutrient transport system
Support

3. Land adaptations Cuticle: Waxy coating prevents water loss
Stomata: pores that open/close to permit gas exchange
Roots & Stems: support
Vascular system: tissue that transports nutrients
Nutrients & water go up plant
Sugars go down the plant

5. General Plant Life Cycle
Alternation of generations
Gametophyte (haploid)
Begins with spores created by meiosis
Mature gametophyte grows by mitosis
Male & female organs
Sperm & egg created

6. General Plant Life Cycle
Sporophyte (diploid)
Begins when sperm fertilizes egg (zygote)
Zygote divide by mitosis to create a mature sporophyte
Meiosis produces haploid cells

7. Mosses Nonvascular, seedless Grow low to ground to retain moisture
Lack true leaves
Leaf-like structures only 1 cell thick
Rhizoids anchor into soil
Early inhabitant of new ecosystems (succession)

8. Moss Life Cycle Gametophyte phase Sporophyte 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
Sporangia houses haploid spores
Spores land and new gametophyte grows

10. Ferns Seedless, vascular plants
Vascular: allows taller growth
Rhizoids: underground stems draw nutrients
Fronds: leaves uncurl
sporangia on underside
Sori: sporangia

11. Fern Life Cycle Sporophyte phase Gametophyte phase Dominant stage
Sporangia produces haploid spores
Spores released into air
Gametophyte phase
Spore grows into prothallus
Archegonium: produces female egg
Antheridium: produces male sperm
Sperm swims to egg
Zygote begins sporophyte stage

13. Conifers Seed advantages Conifers: woody cone houses seeds
Don’t depend on water
Protects & nourishes embryo
Allow plants to grow in new locations
Conifers: woody cone houses seeds
Male cones: produce pollen
Female cones: produce egg
Pines, redwoods, spruce, cedar

14. Conifer Life Cycle Sporophyte phase Cones grow on tree Female cones
Megaspores inside archegonia (gametophyte)
Male cones
Microspores (gametophyte) released from antheridia
sticks to archegonium
Pollen tube grows from pollen
Sperm travels down pollen tube (zygote/seed created)
Sporophyte stage restarts

15. female
male

16. Flowers Reproductive structure of flowering plants Sepals
outer ring of leaves
protection
Petals
Inner ring of leaves
Brightly colored to attract pollinators
Open petals & sepals reveal male and female structures

17. Flowers Female Carpal Male Stamen Inner most part
Ovary: within the base (female gametophyte)
Style: long stalk
Stigma: sticky tip, collects pollen
Male Stamen
Surrounds carpal
Filaments: long stalks
Anther: produces pollen (male gametophyte)

18. 1) Flower matures and opens

19. 2) Microspores (male gametophytes) created in the anthers

20. In the Anthers Meiosis makes 4 microspores In each microspore
Nucleus splits in two
1 nucleus: forms pollen tube
1 nucleus: splits again to make 2 more nuclei
1 nucleus: fertilizes the egg
1 nucleus: fuses to make endosperm

21. 3) Microspores continue to develop

22. 4) Ovaries divide by meiosis to create megaspore

23. In the Ovules Meiosis makes 4 megaspores (only 1 survives)
In megaspore
Mitosis creates 8 nuclei
1 nucleus: egg cell
2 nuclei: form embryo sac
5 nuclei: disintegrate

24. Microspore lands on stigma

25. 5 & 6) Pollen tube grows from pollen
Two sperm nuclei follow down the pollen tube

26. 7) Double fertilization:
1 sperm nuclei fuses w/ egg (zygote created)
1 sperm nuclei fuses w/ the embryo sac (endosperm created)

27. 8) Ovule hardens to form seed

28. Seed germinates

29. Fruit Production In the seed Embryo Endosperm
Surrounding ovary grows into a fruit
Fruit attracts animals to eat and spread the seeds
Fruit seeds in fox droppings

30. End of the Semester!