3-2 Notes – Plant Reproduction Chapter 3 Lesson 2

Alternation of Generation “Alternation of generations” describes the life cycle of organisms, such as plants, that alternate between diploid stages and haploid stages.

Alternation of Generation In seedless plants, the haploid generation lives on its own. In seed plants, the haploid generation lives inside diploid tissue.

Seedless Plant Reproduction Examples: mosses and ferns They grow from haploid spores, not seeds Spores grow by mitosis and cell division to form haploid plants.

Seedless Plant Reproduction Fertilization results in a diploid zygote that grows by mitosis and cell division into the tiny diploid generation.

Seed Plant Reproduction Most plants are seed plants.

Seed Plant Reproduction Sperm cells form inside a protective structure called a pollen grain.

Seed Plant Reproduction Egg cells form inside a female reproductive structure called an ovary.

Seed Plant Reproduction In pollination, pollen grains from the male structure reach the female structure.

Seed Plant Reproduction When sperm enters the ovule, fertilization occurs, and a seed develops.

Seed Plant Reproduction

Seed Plant Reproduction A seed consists of: an embryo, food supply, protective covering

Seed Plant Reproduction

Seed Plant Reproduction

Gymnosperms (Flowerless Seed Plants) Gymno- means naked, so these seeds don’t have a fruit covering.

Gymnosperms (Flowerless Seed Plants) Male cones produce pollen grains, and female cones produce eggs. Seeds form as part of the female cone. Female Male

Angiosperms (Flowering Seed Plants) Angio- means vessel, so these seeds do have a fruit covering.

Angiosperms (Flowering Seed Plants) The flower’s male reproductive organ is the stamen. The flower’s female reproductive organ is the pistil.

Angiosperms (Flowering Seed Plants) Pollen grains form in the anther at the stamen’s tip. The filament is a long stalk that connects the anther to the base of the flower.

Angiosperms (Flowering Seed Plants) The pollen grains land on the pistil’s stigma, which is at the top of a long tube called the style.

Angiosperms (Flowering Seed Plants) A pollen tube grows from the pollen grain into the stigma, down the style, to the ovary, where fertilization occurs.

Angiosperms (Flowering Seed Plants) Each ovule and its embryo will become a seed. The fruit of the plant protects the seed and helps with seed dispersal.

Angiosperms (Flowering Seed Plants)

3.2 Plant Reproduction A B C D In alternation of generations, the haploid structures of the diploid generation produces daughter cells called what? A zygotes B spores C pollen D seeds

3.2 Plant Reproduction A B C D What is an immature diploid plant that develops from the zygote of a seed plant called? A embryo B seed C fruit D stigma

What is another name for a flowering seed plant? A zygote B conifer 3.2 Plant Reproduction A B C D What is another name for a flowering seed plant? A zygote B conifer C gymnosperm D angiosperm

Where are pollen grains formed? A anther B ovule C testes D pollen tube

What flower structure becomes fruit surrounding the seed? A stamen SCI 2.a A B C D What flower structure becomes fruit surrounding the seed? A stamen B pollen tube C ovary D pistil

What type of seed plant does not produce flowers? A seedless plants SCI 2.a A B C D What type of seed plant does not produce flowers? A seedless plants B gymnosperms C angiosperms D strawberry plants