Gymnosperms
Group 3: Seed producing, Vascular Plants Gymnosperms Cycads Ginko Conifers Angiosperms
Seeds and their advantages 1) Seed plants don’t depend on water to reproduce Pollen (develops into sperm) carried by wind/animals Seed hardens around zygote 2) Embryo has… Nourishment: Nutrients inside feed embryo Protection: Hard shell 3) Allow dispersal Carried by wind, water, animals Some seeds are “dispersed” by animals Some seeds have “wings”
Seeds and their advantages 1) Seed plants don’t depend on water to reproduce Pollen (develops into sperm) carried by wind/animals Seed hardens around zygote 2) Embryo has… Nourishment: Nutrients inside feed embryo Protection: Hard shell 3) Allow dispersal Carried by wind, water, animals
Seeds and their advantages 1) Seed plants don’t depend on water to reproduce Pollen (develops into sperm) carried by wind/animals Seed hardens around zygote 2) Embryo has… Nourishment: Nutrients inside feed embryo Protection: Hard shell 3) Allow dispersal Carried by wind, water, animals
Group 3: Seed producing, Vascular Plants Type 1: Gymnosperms Conifers have needle-like leaves (reduces water loss) Common to lumber industry Seeds enclosed in cones Male cones: produce pollen (pollen cone) Female cones: produce eggs (seed cone) Seed hardens around zygote (protected inside cones) Ex: Evergreen, Pine, Redwood, Cedar
Conifer Life Cycle . Sporophyte phase (dominant) Cones grow on tree Male cones Spores created by meiosis & released Spores develop into pollen (male gametophyte) Female cones Spores created by meiosis Spores develop into female gametophyte Egg forms inside Male pollen lands on female scale Pollen tube grows towards egg Sperm travel down pollen tube Fertilize egg Ovule hardens into seed Seed released & grows into new sporophyte . p seed Z e
Conifer Life Cycle Sporophyte phase (dominant) Cones grow on tree Male cones Spores created by meiosis & released Spores develop into pollen (male gametophyte) Female cones Spores created by meiosis Spores develop into female gametophyte Egg forms inside Male pollen lands on female scale Pollen tube grows towards egg Sperm travel down pollen tube Fertilize egg Ovule hardens into seed Seed released & grows into new sporophyte
1) Male and female seed cones grow on adult sporophytes
2) Pollen grains released from the male seed cones 2) Pollen grains released from the male seed cones -- Pollen is the male gametophyte Let’s zoom into the female seed cone…
3) Pollen grain sticks to the female ovule 4) Pollen tube grows from the male spore 5) Two sperm travel towards the egg - only one sperm fertilizes the egg 6) Diploid embryo develops inside female cone (sporophyte stage restarts)
7) After seeds harden, the cone reopens and the seeds are released
8) Seed will land Ground
9) Seedling grows into (sporophyte)…the cycle repeats Ground
Conifer Life Cycle Diagram
Plant Life Cycle Comparisons Plant type Gametophyte Sporophyte Dominant Phase? Seedless nonvascular (Moss) More familiar, carpet-like plant that produces specialized gametes XX - Archegonium XY – Antheridium Stalk with cup at tip, which is where spores are produced. GAMETOPHYTE Seedless vascular (Fern) Haploid plant body (prothallus) is size of a finger nail, produces both male and female parts More familiar, leafy plant with clusters of spore producing sacs (sori) SPOROPHYTE Seeded vascular Gymnosperm (Conifer) Pollen grains are male gametophytes develpe into sperm, female gameotphytes are microscopic produce eggs More familiar- like pine trees, produces male and female cones that produce spores
Review Name three advantages of seeds. Which structure will protect gymnosperm seeds? What do male cones produce? What do female cones produce? What is created when the sperm and egg fuse: sporophyte or gametophyte? What is the male gametophyte? Female? What is it called when pollen reaches the female ovule? What is created?