1. Gymnosperms
Chapter 5
Section 2

2. What are Gymnosperms Seed Plant Naked seeds
Not enclosed in a protective covering
Needlelike or scale-like leaves
Deep growing root system
Examples
Shrubs
Most are trees

3. Types of Gymnosperms Cycads
175 million years ago most plants were Cycads
Now mainly in tropical regions
Look like palm trees with cones
Large cones

4. Types of Gymnosperms Ginkgo Only one species Ginkgo biloba
Survival due to Chinese and Japanese
Can grow as tall as 25 meters
Can tolerate pollution

5. Types of Gymnosperms Gnetophytes Least likely to see
Live in hot dry deserts of South Africa and deserts of western United States
Some are trees, shrubs or vines

6. Types of Gymnosperms Conifers Cone bearing plants
Largest, most diverse group
Pines, redwoods, cedar, hemlocks, junipers
Evergreen plants
Keep leaves (needles) all year

7. Reproduction Cones are the reproductive structure
Most gymnosperms produce two kings of cones
Male (pollen cone)
Female (egg cone)
Most plants produce both types of cones

8. Male cones Female cones Smaller than female
Produce tiny grains of pollen
Will later become sperm
Male cones produce so many grains of pollen they can overflow the spaces between the cone’s scales.
Female cones
Contain at least one ovule
Structure that contains the egg cell
After fertilization the ovule will become the seed

9. Reproduction Life Cycle Pollen falls from make cone onto female cone
Sperm and egg join in ovule of female cone
Zygote develops into embryo part of seed

10. Pollination and Fertilization
Transfer of pollen from the male reproductive structure to the female reproductive structure
Wind transfers the pollen
Pollen collects on sticky substance around ovule
Scales of female cone close to seal in the pollen
Fertilization occurs
Seed develops on the scale
Female cones stay on tree until seed are mature
Could take years
Male cones fall from tree when they lose their pollen

11. See Dispersal Female cone increases in size as seed grows
Orientation on tree changes
Immature seed- cone points upward
Mature seed- cone points downward
When seeds are mature
Cone opens
Wind shakes seeds from cones and carries them away
Only a few seed will land in suitable surroundings

12. Gymnosperms and the Living World
Products from conifers
Paper, wood products
Used for rayon in clothes
Turpentine and rosin from sap
Clear cutting
All trees in a large area are cut down