Plants Life Cycles (22-2,3,4)

Moss – Bryophytes – seedless, non-vascular plants. A. Gametophyte –Dominant plant that produces gametes in two types of reproductive structures. 1. Antheridium – Male structure, produce flagellated sperm know as pollen grains. 2. Archogonium – Female structure that produce a single egg also know as an embryo sac.

B. Moss Life Cycles steps 1. Sperm swims to the archogonium and fertilize the egg forming a zygote. 2. Zygote forms into a non- photosynthetic sporophyte that develops on the top of the gametophyte for nourishment.

3. A sporangium filled with spores, (haploid Reproductive Cell) forms at the top of the stalk. a. It produces one type of spore. This production is called Homospory. (homosporous) 4. The spore is release and grows into a protonema, (a filament stage) that develops into a gametophyte.

Mature sporophyte (2N) Gametophyte (N) Young sporophyte (2N) Zygote (2N) Sperm (N) Egg (N) Spores (N) Capsule (sporangium) Protonema (young gametophyte) (N) Male gametophyte Female gametophyte Antheridia Archegonia

Moss

Moss

Hornworts

Liverworts

Seedless Vascular plants Chapter 22 Section 22:3 Seedless Vascular plants

II. Fern- Seedless vascular plants Sporophyte- Is the dominant plant, photosynthetic, homosporous, that produces haploid spores. 1. Sori are brown dots found on the underside a ferns leaf, made up of sporangia which are filled with spores.

a. Sori are only found on the underside of a mature ferns leaf called a FROND. 1. The sporangia’s that make up the sori are filled with haploid spores that when released, could germinate into gametephytes.

Sori

Sporangium

Middle structure is the spore of a fern.

2. Spores will germinate into heart shaped gametophytes that contains both male and female reproductive structures. 3. A young sporophyte will grow from the heart shaped structure when the egg gets fertilized. 4. It will than grow into a mature sporophyte which will contain sorus.

Heart shaped gametophyte

Sporophyte growing out of a heart shaped gametophyte of a fern

Chapter 22 Section 22:4 Seed Plants Gymnosperms

III. Conifers- Gymnosperms A. Produces 2 types of spores (Heterosporous) 1. Male microsporangia (pollen sac) produces microspore (pollen grain) which develop into a microgametophyte. 2. Female megasporangia – produces megaspores (egg) which develop into a megagametophyte.

B. Pine tree life cycle: 1. Pine trees produce male and female cones. a. Male cone released pollen reaches female cone. b. Pollen forms a pollen tube and take one year to reach the egg.

Male and female cones

c. One sperm fertilizes egg through an opening called the micropyle. d. Zygote develops into an embryo and the ovule develops into the seed. e. One year later the cone opens and the mature seeds are released for germination.

MIcropyle opening

5. What is a seed? A. A reproductive package that contains a plant embryo and a supply of stored food, called endosperm, inside a protective coating. B. Seeds are resistant to drying out C. By producing a seed a plant seals its next generation into a protective package. D. Special structures on seed enable it to be distributed elsewhere.

Conifer Mature seed ready for germination…