1. Section 3: Seed Plants

2. Key Ideas
What are the two groups into which seed plants are classified?
What characterizes reproduction in seed plants?
What are the four major groups of living gymnosperms?
What characterizes reproduction in a conifer?

3. Kinds of Seed Plants Gymnosperms
Seed plants whose seeds do not develop within a fruit. Most of these seeds develop in a cone
Greek words gymnos, meaning “naked,” and sperma, meaning “seed”
Angiosperms
seed plants whose seeds develop enclosed within a fruit
Fruits develop from part of a flower
Flowering plants
Greek words angeion, meaning “case,”

4. Visual Concept: Characteristics of Vascular Plants With Seeds

5. Reproduction in Seed Plants
do not require water to reproduce sexually.
greatly reduced gametophyte and a dominant sporophyte.
female gametophyte develops inside an ovule,
a multicellular structure that is part of the sporophyte

6. Reproduction in Seed Plants, continued
The male gametophyte of seed plants develops inside a pollen grain.
The transfer of pollen grains from the male to the female reproductive structures is called pollination.
The fusion of an egg and sperm is called fertilization.
After fertilization, the ovule is called a seed and contains an embryo.

7. Reproduction in Seed Plants, continued
Seeds are dispersed, or scattered, from the parent plant to locations where the embryos in the seeds develop into new sporophytes.
Dispersal may prevent competition for water, nutrients, light, and living space between parents and offspring.
Many seeds have structures that help wind, water, or animals carry them away from their parent plant.

8. Gymnosperms
There are four major groups of gymnosperms: conifers, cycads, ginkgoes, and gnetophytes.
Conifers are the most familiar gymnosperms.
needle-like leaves
pine trees and redwoods.

9. Visual Concept: Characteristics of Gymnosperms

10. Visual Concept: Types of Gymnosperms

11. Life Cycle of a Conifer dominant sporophyte wind pollination
the development of seeds in cones.
The gametophytes develop in cones
circles of modified leaves called scales.
Many gymnosperms produce both female and male cones on the same plant.

12. Visual Concept: Life Cycle of Conifers