ASEXUAL AND SEXUAL REPRODUCTION

1. ASEXUAL AND SEXUAL REPRODUCTION BY ANNA OLIVA

2. ASEXUAL REPRODUCTION • It is the formation of new individuals from the cell(s) of a single parent. • It is most common in plants but it can find place even in animals • It does not involve fusion of gametes • Offsping become genetically identical

3. SEXUAL REPRODUCTION • Two individuals produce offspring that have genetic characteristics from both parents. Sexual reproduction introduces new gene combinations • It involves the union or fusion of a male and a female gamete • This is how humans and most animals reproduce

4. THE END!

5. HIHI JUST KIDDING!

6. SEXUAL REPRODUCTION IN PLANTS BY (STILL) ANNA OLIVA

8. The flower is the reproductive organ of a plant • It’s reproductive portions are the stamen, consisting of the filament and the anther which has pollen grains that contain male gametes • The stigma, style and ovary instead make the female part of the plant which is called carpel • The ovary has ovules which contain the female gametes

9. LETS NOW UNDERSTAND HOW REPRODUCTION IN PLANTS WORKS

10. FROM POLLINATION... • Pollination and fertilization are the two main events for reproduction • Pollination is the transfer of pollen from the anther to the stigma of the pistil • When pollen from a plant's stamen is transferred to that same plant's stigmait is called self-pollination • When instead it is transferred to a different plant's stigma, it is called cross-pollination, it produces stronger plants but they must be of the same species

11. TO FERTILIZATION • The stigma, because of it’s stickiness, receives pollen grains in different ways • Pollen trapped by the stigma pollinates to produce a long tube that travels down the style and enters the ovaries • The pollen tube contains the male gamete which fuses with the female gamete in the ovule, this fusion process is called fertilization • The ovule, when fertilized, transforms in the seed, after they are formed the ovary matures to produce fruit • New plants grow from the seeds and this is the process by which plants propagate themselves

13. DIFFERENT WAYS FOR POLLINATION TO OCCUR • Plants rely on animals or wind to pollinate them. • When animals such as bees, pollinate plant accidentally because they are actually at the plant to get food from the sticky pollen or a sweet nectar made at the base of the petals. While feeding, the animals accidentally rub against the stamens and get pollen stuck all over themselves. When they move to another flower to feed, some of the pollen can rub off onto this new plant's stigma. • Plants that are pollinated by animals often are brightly colored and have a strong smell to attract the animal pollinators. • Another way plants are pollinated is by the wind. The wind picks up pollen from one plant and blows it onto another. • Plants that are pollinated by wind often have long stamens and pistils. Since they do not need to attract animal pollinators, they can be dully colored, unscented, and with small or no petals since no insect needs to land on them. • Is some cases humans hand also occur..(but we will see and example later)

14. THE BEE

15. POLLEN • Grain of pollen: microscopic part produced by the anther that serves as the male agent of fertilization in flowering plants. • Thickening of cellulose: fibrous thickening. • Exine: outer layer of a pollen grain. • Intine: inner layer of a pollen grain. • Nucleoli: control centers of cellular activity. • Pore: small hole.

16. WE ARE FINISHED BUT LET ME TELL YOU AN INTERESTING EXAMPLE ABOUT HOW HUMANS IN SOME CASES HELP POLLINATION

17. VANILLA (you do not have to copy this guys) ;) • The world's most expensive spice, vanilla is an orchid • In its native Central America, the vanilla flower is pollinated by a small bee the morning the flower opens • To ensure seed pods are formed in cultivation, humans must be the pollinator, manually transferring pollen to the stigma of the flower • As vanilla flowers last only one day, the pollination must occur in the morning after the flower first opens • Seed pods formed by pollinating a flower with its own pollen will not contain seeds that will germinate

19. QUESTIONS(yuppie!) • OF WHAT ARE THE MALE AND FEMALE PARTS OF A PLANT COMPOSED? • WHAT ARE THE WAYS FOR POLLINATION TO OCCUR? • HOW IS THE SEED FORMED?

20. NOW I REALLY AM DONE!THANK YOU FOR YOU ATTENTION 3B AND I HOPE YOU HAVE LEARNED SOMETHING  (I will leave you with a song ) http://www.mbgnet.net/bioplants/pollensong.html