1. Apply Concepts Pollination is a process that occurs only in seed plants. What process in seedless plants is analogous to pollination

2. Review Describe how fertilization takes place in a gymnosperm

3. Classify Make a table with two columns labeled haploid and diploid and assign each of the following structures from the pine life cycle to the appropriate column: Pollen tube, Seed cone, Embryo, Ovule, Seedling

CH 22 INTRODUCTION TO PLANTS

22.3 Seed Plants

The Importance of Seeds

Adaptations of seeds Plants reproduce without open water Transfer of sperm by pollination Protection of embryos in seeds.

Seed

Plant embryo and a food supply encased in a protective covering

Living plant within a seed is diploid and represents the sporophyte phase.

Male gametophytes and the female gametophytes grow and mature directly within the sporophyte

Gymnosperms Bear seeds directly on the scales of cones

Angiosperms Bear seeds in flowers inside a layer of

tissue that protects the seed.

Pollen Grains

Contains entire male gametophyte Carried to the female reproductive

structure by wind or animals Pollination

Transfer of pollen from the male reproductive structure to the female reproductive structure.

Zygote contained within a seed grows into a tiny plant- the sporophyte embryo

Embryo begins to grow under right conditions

Uses nutrients stored in the seed until it can carry out photosynthesis on its own

Seed coat Surrounds and protects the embryo and

keeps the contents of the seed from drying out.

Seed cones produce female gametophytes

Female gametophytes develop in two ovules at base of scale.

Pollen cones produce pollen grains, which make up the entire male gametophyte stage

One haploid nuclei will divide later to produce two sperm nuclei.

Development Inside Seeds

Pollen tube Structure containing two haploid sperm

nuclei.

Development Inside Seeds

Pollen grain lands ovule Splits open and begins to grow a pollen

tube Reaches the female gametophyte

One sperm nucleus disintegrates Other fertilizes the egg.

Fertilization produces a diploid zygote Grows into an embryo.

Seed is an encased embryo that is ready to be scattered by the wind and grow into a plant.

Reproduction in conifers occurs in cones from the mature sporophyte plant.