spore pollen grain ovule seed angiosperm stamen anther 3.2 Plant Reproduction filament pistil stigma style ovary pollen tube fruit

What is alternation of generations? –One generation has primarily diploid cells, the other generation has only haploid cells. –Organisms that alternate between diploid and haploid generations have an alternation of generations. Some organisms, including plants, have two life stages called generations. 3.2 Plant Reproduction

What is alternation of generations? (cont.) 3.2 Plant Reproduction

How do seedless plants reproduce? Seedless plants, such as mosses and ferns, grow from haploid spores, not seeds. –Haploid spores that grow by mitosis and cell division into haploid plants. –Fertilization results in a diploid zygote that grows by mitosis and cell division into the diploid generation. –The diploid generation produces haploid spores by meiosis, and the cycle repeats. 3.2 Plant Reproduction

How do seed plants reproduce? Most of the land plants that cover Earth grew from seeds—called seed plants. –There are flowerless seed plants and flowering seed plants. –The haploid generation is within diploid tissue. –Separate diploid male and diploid female reproductive structures produce haploid sperm and haploid eggs. 3.2 Plant Reproduction

The Role of Pollen Grains A pollen grain forms from tissue in a male reproductive structure of a seed plant. Pollination occurs when pollen grains land on a female reproductive structure of a plant of the same species. 3.2 Plant Reproduction

The Role of Ovules and Seeds The female reproductive structure of a seed plant contains one or more ovules. After fertilization, a seed develops from the ovule. 3.2 Plant Reproduction

Flowerless Seed Plant Reproduction In flowerless seed plants—gymnosperms— the seeds are not surrounded by a fruit. –Cones are the male and female reproductive structures of conifers. –Male cones produce pollen grains. –Female cones produce eggs. –Seeds form as part of the female cone. 3.2 Plant Reproduction

Flowering Seed Plant Reproduction Flowering seed plants—angiosperms— include most of the plants you see. 3.2 Plant Reproduction Seed Plants Fruits and vegetables come from flowering seed plants.

Reproduction and the Flower A typical flower has male and female reproductive organs surrounded by petals. The stamen is the male reproductive organ. Pollen grains form at the tip of the stamen, in the anther. The filament is a long stalk that supports the anther and connects it to the base of the flower. 3.2 Plant Reproduction

Reproduction and the Flower (cont.) The female reproductive organ of a flower is the pistil. Pollen can land at the tip of the pistil on the stigma, which is at the top of a long tube called the style. At the base of the style is an ovary containing one or more ovules which eventually will contain a haploid egg. 3.2 Plant Reproduction

Reproduction and the Flower (cont.) 3.2 Plant Reproduction

An Angiosperm’s Cycle 3.2 Plant Reproduction

Fruit and Seed Dispersal Fruits and seed are important sources of food for people and animals. Fruits and seeds can be dispersed by: –Air currents –Animals –Water –Gravity 3.2 Plant Reproduction What is the life cycle of a simple plant?

Lesson 2 Review In alternation of generations, the haploid structures of the diploid generation produces daughter cells called what? Azygotes Bspores Cpollen Dseeds 3.2 Plant Reproduction 1.A 2.B 3.C 4.D

Lesson 2 Review What is an immature diploid plant that develops from the zygote of a seed plant called? Aembryo Bseed Cfruit Dstigma 3.2 Plant Reproduction 1.A 2.B 3.C 4.D

Lesson 2 Review What is another name for a flowering seed plant? Azygote Bconifer Cgymnosperm Dangiosperm 3.2 Plant Reproduction 1.A 2.B 3.C 4.D