2.2 Asexual and Sexual Reproduction

1. G.O.2: As species reproduce. Characteristics are passed from parents to offspring. 2.2 Asexual and Sexual Reproduction

2. Reproduction • Reproduction produces new individuals of a species. • The way a species reproduces determines how much variation the new individuals will have. • Reproduction can produce new individuals that are identical to or very different from one another • Asexual Reproduction – involves one individual, all of the offspring are identical to that parent • Sexual Reproduction – usually involves two individuals, the offspring will have a mix of characteristics from both parents

3. Asexual Reproduction • Type of reproduction with only one parent. Each offspring is identical to the parent (how is this different than sexual reproduction?) • Types of asexual reproduction: • Budding • Binary Fission • Spore reproduction • Vegetative reproduction

4. Asexual Reproduction • There are 4 ways that organism reproduce asexually: • Binary Fission • Budding • Spore Production • Vegetative Reproduction

5. Asexual Reproduction • Binary Fission: Cell splits in two and produces two identical organisms.http://www.youtube.com/watch?v=3cD3U2pgb5w • Budding: parent organism produces a smaller version of itself (known as a bud). The bud eventually detaches from the parent and becomes an independent organism which is exactly the same as the parent.http://www.youtube.com/watch?v=489CSop00sY

6. Budding barrel sponge Budding sea sponges Budding tube sponge

7. Asexual reproduction • Spore production – Spores are like seeds but are produced by one parent (seeds require two parents). The spore is identical to the parent. Mould Spores

8. Spores forming on lichen Spores forming on a fern Spore forming bacteria

9. Types of Asexual Reproduction: 4) Vegetative Reproduction – reproduction that does not involve the formation of a seed • Many plants reproduce this way, but there is more than one method of vegetative reproduction • Each method involves taking a cutting of the parent plant, which will eventually grow identical to the parent

10. Vegetative Reproduction Pg. 31 Runners Aspen suckers Grafting

11. Sexual Reproduction • Reproduction with two individuals. Most plants and animals reproduce sexually. The offspring has a mix of characteristics of both parents.

12. Sexual Reproduction in Animals • Sexual reproduction in animals: • http://www.youtube.com/watch?v=POJAQX760VY&feature=fvsr

13. Sexual Reproduction in Animals • General process of animal reproduction is similar (from fungi to protists to dragonflies to bears; small details vary) • Involves gametes (sex cells) • Male gametes = Sperm Cell • Female gametes = egg Cell (Ova) • Union of the two gametes during mating is called fertilization • The fertilized cell created is known as the Zygote • The zygote undergoes continuous divisions (cleavage) to create a multicellular life form called the embryo

14. Sexual Reproduction in Animals • The cell division will take place inside the female (most mammals) or outisdein an egg (most other animals) • Remember: The embryo is not identical to either parent; it will have a mix of characteristics from both parents

15. Sexual Reproduction in Animals • Only one of the many sperm cells surrounding the egg will fertilize the egg. • InfoBit: Hermaphrodites • Common garden worms and slugs are hermaphrodites. They can produce both math and female gametes. • Although most slugs and worms usually prefer to mate with other individuals of their species, in times of environmental stress, they can fertilize themselves.

16. Sexual Reproduction in Plants • Sexual reproduction in plants: • http://www.youtube.com/watch?v=FsBQQDg5GIw

17. Sexual Reproduction in Plants • As in animals, sexual reproduction requires the joining of a male and female gametes to create a zygote, and with continued division, an embryo • Most plants produce both male and female gametes; some only produce one or the other • Pollen contains the male gametes (found in the stamen) • Ovules contain the female gametes (found in the pistil)

18. Sexual Reproduction in Plants Pistil • You will need to know all of the structures involved in plant reproduction. • Stamen • Filament • Anther • Pistil • Stigma • Style • Ovary • Ovule • Sepal • Petal • Receptacle

19. Sexual Reproduction in Plants • Pollination occurs when pollen is transferred from the anther of the stamen to the stigma of the pistil. • Fertilization occurs when the male and female gametes unite • Cross-Pollination occurs when the pollen of one plant is carried to the stigma of another by wind, water, or animals, such as bees or butterflies • Cross-fertilization occurs when a grain of this pollen produces a long tube that eventually grows down the style into the ovary that contains the ovules

20. Asexual Reproduction Sexual Reproduction Advantages • Provides lots of variation which helps the species survive environmental change Disadvantages • Takes a lot of energy and time; means limited offspring can be produced Advantages • Does not require specialized cells or a way of uniting gametes • Can produce lots of offspring very quickly Bacteria: 1  10 million in 12 hr Disadvantages • If conditions become unfavorable, the entire population may be wiped out (because they are identical) • So all 10 million bacteria could be wiped out by the same antibiotic

21. Asexual or Sexual • Some species have the ability to reproduce both sexually and asexually. • In plants, seeds can often be produced sexually and asexually. If the seeds don’t have a contribution from a sperm cell they will be genetically identical to the parent (i.e. _____________, sunflowers, roses) • In animals, aphids, sponges, __________ and moss can alternate between asexual and sexual reproduction