1 / 28

Ch. 24- Reproduction of Seed Plants

Ch. 24- Reproduction of Seed Plants. Haploid Diploid. I. Reproduction With Cones and Flowers A. Alternation of Generations - All plants have a life cycle in which a diploid sporophyte generation alternates with a haploid gametophyte generation. MEIOSIS. Gametophyte Plant (N).

keegan-avila
Download Presentation

Ch. 24- Reproduction of Seed Plants

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ch. 24- Reproduction of Seed Plants

  2. Haploid Diploid • I. Reproduction With Cones and Flowers • A. Alternation of Generations • - All plants have a life cycle in which a diploid sporophyte generation alternates with a haploid gametophyte generation. MEIOSIS Gametophyte Plant (N) Sporophyte Plant (2N) FERTILIZATION

  3. B. Life Cycle of Gymnosperms • - Reproduction in gymnosperms takes place in cones, which are produced by a mature sporophyte plant. • 1. Pollen cones • a. Also called malecones. • b. Produces the male gametophytes, which are called pollengrains.

  4. 2. Seed Cones • a. Produce female gametophytes • b. Much larger than pollen cones • c. At the base of each cone scale are found 2 ovules in which the female gametophytes develop

  5. 3. Pollination – The pollen is carried by the wind and caught on a sticky secretion (pollination drop) on one of the scales of the female cone.

  6. 4. Fertilization • a. When a pollen grain lands near an ovule, it grows a pollentube into the ovule. • b. A sperm from the pollen tube fertilizes the egg in the ovule.

  7. Development a. Fertilization produces a zygote which grows into an embryo b. The embryo becomes enclosed in a seed

  8. ANGIOSPERM • C. Structure of Flowers • - Flowers are the reproductive organs that are composed of four kinds of specialized leaves: sepals, petals, stamens, and carpels. (Figure 24-5)

  9. Pistil Stamen Style Stigma Anther Filament Ovary Petal Sepal Ovule

  10. 1. Sepals • a. The outermost circle of floral parts contains the sepals, which in many plants are green and closely resemble ordinary leaves • b. Enclose bud and protect the flower during development

  11. 2. Petals • a. Brightly colored and found just inside the sepals • b. Attract insects and other pollinators to the flower

  12. 3. Stamens • a. Produce male gametophytes – pollen grains • b. Consists of anther and filament

  13. 4. Carpels • a. Also called pistils • b. produce female gametophytes – eggs • c. Consists of ovary, style, and stigma

  14. D. Life Cycle of Angiosperms • 1. Reproduction in angiosperms takes place within the flower • 2. Following pollination and fertilization, the seeds develop inside protective structures

  15. E. Pollination • 1. Most gymnosperms and some angiosperms are wind pollinated, whereas most angiosperms are pollinated by animals. • 2. Insect pollination is more efficient than wind pollination, giving insect-pollinated plants a greater chance of reproductive success.

  16. F. Fertilization in Angiosperms • 1. Double Fertilization – Inside the embryo sac, two distinct fertilizations take place • a. First, one of the sperm nuclei fuses with the egg nucleus to produce a diploid zygote, which will grow into the new plant embryo.

  17. b. Second, the other sperm nucleus fuses with two polar nuclei in the embryo sac to form a triploid (3N) cell. This will grow into a food-rich tissue know as endosperm, which nourishes the seedling as it grows.

  18. II. Seed Development and Germination • - the development of the seed, which provides protection and nutrition for the embryo, was a major factor in the success of plants on land.

  19. A. Seed and Fruit Development • 1. As angiosperm seeds mature, the ovary walls thicken to form a fruit that encloses the developing seed. • 2. The term fruit, biologically speaking, applies to any seed that is enclosed within its embryo wall.

  20. http://www.youtube.com/watch?v=bwCpQflmQG4

  21. http://www.youtube.com/watch?v=zVNsCW6eiiw

  22. B. Seed Dispersal • 1. Dispersal by Animals- Seeds dispersed by animals are typically contained in fleshy, nutritious fruits.

  23. 2. Dispersal by Wind and Water- Seeds dispersed by wind or water are typically lightweight, allowing them to be carried in the air or to float to the surface of the water.

  24. C. Seed Dormancy • 1. Some seeds sprout rapidly while other seeds enter a period of dormancy, during which the embryo is alive but not growing. • 2. Environmental factors such as temperature and moisture can cause a seed to end dormancy and germinate.

  25. D. Seed Germination • - The early growth stage of the plant embryo

More Related