SEXUAL REPRODUCTION IN

SEED PLANTS

I. REPRODUCTIVE STRUCTURES OF

SEED PLANTS

1. Gametophyte is extremely small2. Spores are not released- remain in

tissue of sporophyte and develop into the gametophytes (male and femaleA. Pollen grain- immature male gametophyteB. Ovule- multicellular structure that is part of the sporophyte where the female gametophyte develops

3. Following fertilization, the ovule and its contents develop into a seed

A. GYMNOSPERMS AND ANGIOSPERMS

1. Wind and animals transport pollen grains to ovulesA. Pollination- transfer of pollen grains from the male reproductive structure to the female reproductive structure

B. Pollen Tube- tube that emerges from the pollen grain and grows to the ovule to pass sperm directly to the egg

B. REPRODUCE SEXUALLY WITHOUT WATER

I. SEEDS

1. Seeds contain the embryo of seed plants

2. Plant embryo is a new sporophyte3. Seeds form from an ovule after the

egg has been fertilized

A. REVIEW

1. Seed Coat- outer layers of the ovule that harden as the seed maturesA. offers protectionB. seeds germinate at different times, in different conditions, or must be exposed to light. The seed coat helps maintain the seed until that time

2. Endosperm- tissue that provided nutrients for the embryo

3. Cotyledon- seed leafA. transfer nutrients to the embryoB. Monocots- 1 cotyledon, Dicots- 2 cotyledons

B. SEED STRUCTURES

II. CONES

A. Seed plants are the most successful plants1. Angiosperms-ovules that are completely enclosed

2. Gymnosperms- ovules enclosed after pollination

B. Gametophyte of gymnosperm develops in cones1. whorls of modified leaves2. male pollen cones or female seed cones

C. Pollination1. pollen grains carried by wind to female cone

2. during pollination, female cones are open to expose ovules

3. pollen tube grows into the ovule4. sperm enters ovule5. seed cone closes after pollination and remains closed until the seeds mature, which can take up to two years

1. The zygote and ovule develop into a seed which grows into a new sporophyte

2. An adult pine tree produces male and female cones

3. Meiosis occurs4. Male and female spores form on the scales

of the cones5. Spores develop into male and female

gametophytes6. After pollination, sperm enter the ovule

through a pollen tube and fertilization occurs

D. LIFE CYCLE OF A CONIFER

IV. FLOWERS

B. Structure of a Flower- arranged in 4 concentric whorls1. sepals- outermost whorls that protect the flower from damage while still a bud

2. petals- 2nd whorl that attracts pollinators3. stamens- 3rd whorl that produces pollen

A. Anther- pollen producing sac4. pistils- 4th whorl which produces ovules that develop in the swollen lower part which is called the ovary and has a style, which rises from is

A. ANGIOSPERMS, GAMETOPHYTES DEVELOP IN FLOWERS

C. flowers may or may not have all 4 whorls1. complete flowers have all four2. incomplete flowers lack one or more of the whorls

3. perfect flowers contain stamen and pistils4. imperfect flowers lack a stamen or pistil

D. flowers attract insects that pick up pollen from the stamen and take it to pistils of that flower or other flowers when they pick up the flower’s nectar

1. the zygote and ovule develop into a seed which grows into a new sporophyte

2. a flower produces male spores inside its anthers and the female spores inside its pistil

3. meiosis occurs4. spores develop into male and female

gametophytes5. pollination occurs when a pollen grain lands

on the stigma of a pistil6. sperm enters an ovule through a pollen

tube and fertilization occurs

E. LIFE CYCLE OF AN ANGIOSPERM

V. ASEXUAL REPRODUCTION

A. Vegetative reproduction is the growth of new plants from non-reproductive plant parts, like stems, roots, and leaves

B. Kalanchoes are succulents that are often grown as potted plants and readily reproduce either vegetatively or by seeds

C. People often grow plants from their vegetative structures which is called vegetative propagation