Passing it On

1. Passing it On Unit A: Topic 3

2. Living organisms display a wide variety of methods or reproductive strategies for passing on their genetic information to their offspring.

3. Asexual Reproduction • Involves only one parent • Offspring are identical to the parent • Four main types of asexual reproduction are: • Binary fission • Budding • Spore Production • Vegetative Reproduction

4. Binary Fission • Occurs in unicellular organisms • Cell splits in two producing identical offspring • Examples: Bacteria and protists • http://www.youtube.com/watch?v=NTBzPP0Aygk&feature=related

5. Budding • Parent produces a small, attached version of itself. • The offspring can stay connected or detached • Examples: Coral, yeast, hydra. • http://www.youtube.com/watch?v=489CSop00sY

6. Spore Production • Similar to seeds • Produced by the division of parent cells. • Examples: Fungi, ferns, moulds, and algae. • Many spores are produced to ensure some survival. • Some fungi and algae produce zoospores which move with a tail-like flagella http://www.youtube.com/watch?v=eZ40LDWt678&feature=related

7. Vegetative Reproduction • There are many different types including runners, tubers and suckers. • Examples: Strawberry plants, potatoes, and aspen trees. • http://www.youtube.com/watch?v=fPraEesXRSs

8. Asexual Reproduction • Asexual reproduction can also happen without special cells. • In the meristem of plants, found in the tips of roots and stems, cells rapidly divide. • Cutting from a parent stem may be used to produce new plants that clones (exact copies) if that stem is planted. http://www.youtube.com/watch?v=ZLGz-Ykzxqo

9. p. 29

10. pollen grains pedicel

11. Go through the Structure of Plant

12. Sexual Reproduction in plants • Most plants will produce both male and female gametes in one plant, but some only produce male or female gametes. • Pollen, which is found on the stamen, has the male gametes in it. • Ovules, which are found on the pistil, contain the female gametes.

13. Pollen • Self-Pollination: when the pollen from the anther is transferred to the stigma. • Cross-pollination: when the pollen from one plant is carried to a different plant. • http://www.youtube-nocookie.com/embed/xHkq1edcbk4?rel=0 THE BEAUTY OF POLLINATION (4 MIN) • How can pollination occur? • Wind, water, animals/birds

14. Fertilization • Fertilization: When the gametes in the pollen join with the gametes in the ovum (on the same plant). • Cross-fertilization: When the pollen from one plant fertilizes another plant. • http://www.youtube.com/watch?v=KMQtLWpAdXI&feature=related

15. Sexual Reproduction in plantshttp://www.teachersdomain.org/asset/oer08_vid_flowers • Pollen grains, each of which contains a sperm nucleus, are brought to the female eggs in the ovaries. • The pollen grain grows an extension called a pollen tube. This pollen tube grows until it reaches the ovule. • The sperm nucleus travels down the tube to fertilize the egg. • A zygote is formed and contains the genetic information from both parents. • It then goes through many cell divisions to form a multicellular embryo containing miniature leaf, root, and stem. • The embryo is protected by a seed and can stay dormant for a long time.

16. Sexual Reproduction in animals • Involves specialized sex cells called gametes • Fertilization – the union of sperm and egg

17. Sexual Reproduction in animalshttp://www.youtube.com/watch?v=UgT5rUQ9EmQ&feature=related • Fertilization can occur internally or externally. • Internal fertilization occurs in insects, reptiles, birds, mammals, some fish and amphibians. • Results in a high rate of success because egg cells are protected. • External fertilization occurs in sponges, most worms, many fish and amphibians. • Results in a low rate of success because egg cells are exposed to harsh climates and predators.

18. Sexual Reproduction in Bacteria • Bacterial Conjugation • A connection forms between two cells. Genetic material is transferred directly from one cell to another • Cells will then go through binary fission to create more cells http://www.youtube.com/watch?v=O-EdX4MaMFE&feature=fvwrel

19. Asexual Reproduction Advantages Disadvantages If conditions are unfavourable, the entire population could be wiped out. • Only need one organism • Doesn’t require any specialized cells to bring gametes together • Can produce lots very quickly

20. Sexual Reproduction Advantages Disadvantages Perfect timing and conditions are required Two partners are needed Takes lots of energy Only produces limited offspring • Provides lots of variation which helps species survive environmental change

21. What are some organisms that reproduce both sexually and asexually? • Some species of grasses • Sunflowers • Roses • Aphids • Sponges • Fungi – some types of fungi can produce asexually by using spores, but they can also produce sexually by using zygospores. Zygospores contain genetic information from two different sources.

22. Review Assignment • What is a zygote and how is it formed? • List three examples of asexual reproduction. • List three ways pollination can occur. • What is similar about sperm and egg cells? What is different? • List the steps of fertilization and embryo development in animal sexual reproduction. • List the steps of fertilization and embryo development in plant sexual reproduction.