Plant Diversity 22-4 & 22-5

1. Plant Diversity 22-4 & 22-5

2. Seed Plants The seed was major step in the evolution of land plants. It allowed plants to be able to colonize dryer areas of land.

3. Seed Plants Adaptations that allow seed plants to reproduce without water include flowers or cones, the transfer of sperm by pollination, and the protection of embryos in seeds.

4. Flowers & Cones C ones are the structures on plants such as pine cones that contain the seeds Flowers are the seed bearing structures on plants like oak trees and rose bushes.

5. Pollen Pollen is the structure that contains the sperm of the plant. Pollen can be transferred from one flower to another in several ways. What are some ways that pollen can be transferred?

6. Seeds Seeds are multicellular structures that contain the developing embryo of a plant. The seeds also contains a stored food supply for the embryo. A seed coat surrounds and protects the embryo as it grows. Find video of seed growth

7. Evolution of Seed Plants As landmasses on Earth became dryer seed plants invaded these areas and eventually become the dominant land plant.

8. Gymnosperms All members of this group have “naked” seeds – seeds are not enclosed/protected by fruit. Gnetophytes – reproductive scales are clustered into cones

9. Gymnosperms Cycads – palmlike plants that reproduce with large cones

10. Gymnosperms Ginkgoes – phylum contains only one extant specie(Ginkgo biloba)

11. Gymnosperms Conifers are the most recognizable and most common gymnosperm

12. Evolution of Conifers The specialized leaves (needles) of conifers are adapted to dry, cool environments. The shape of the needle reduces water loss. They have a thick waxy cuticle on the surface of the needles that also reduces water loss. Needles contain a lot of resin which reduces the number of herbivores that will eat them because they taste so bad. Holes for gas exchange are sunken, this reduces water loss.

13. Angiosperms - Flowering Plants The majority of the members of this phylum have seeds that are enclosed in fruits. Different flower parts give rise the different parts of the fruit.

14. Angiosperms - Flowering Plants Flowers contain the reproductive organs of angiosperms. What evolutionary advantage does a flower give an angiosperm?

15. Angiosperms - Flowering Plants Fertilization is when the sperm and egg unite. During seed development the ovary develops into the fruit.

16. Angiosperms - Flowering Plants The fruit of angiosperms is a wall of tissue surrounding the seed. Fruits are another evolutionary advantage for the success of this group.

17. Diversity of Angiosperms Monocots vs. Dicots– named for the number of seed leaves/cotyledons in the plant embryo. Monoctos have one, Dicots have two Fig. 22-25

18. Diversity of Angiosperms Monocots vs. Dicots– (con’t)

19. Diversity of Angiosperms Monocots vs. Dicots– (con’t)