Question

class 10 science chapter reproduction explain plz urgent

Answer 1

Chapter: How do Organisms Reproduce


 Asexual Reproduction in Plant



 Spore formation → Example: Bacteria, fungi
 Budding → Example: Fungi (yeast)
 Fragmentation → Example: Algae, fungi.
 Vegetative propagationm
 Natural method
 By roots → Example: Sweet potato.
 By stems → Example: Ginger, potato.
 By leaves → Example: Bryophyllum.
 Artificial method
 Cutting → Example: Rose.
 Layering → Example: Strawberry, lemon.
 Grafting → Example: Mango, rose.
 Micropropagation → Example: Orchids, dahlia
 Sexual Reproduction in Plants


 Flower is the reproductive organ.
 It has four whorls – Calyx, Corolla, Androecium, Gynoecuim.
 Calyx and corolla are accessory parts.
 Androecium - Male reproductive organ producing pollen grains.
 Gynoecium - Female reproductive organ having ovule (egg).
 Pollination – Transfer of pollens from anther to stigma for fertilization.
 Fertilization – Fusion of male and female gametes.
 Double fertilization (Triple fusion and syngamy) – unique events in the embryo sac of
ovule


 Asexual Reproduction in Animals


 Fission
 Binary fission → Example:. Amoeba
 Multiple fission → Example: Plasmodium
 Budding → Example:. Hydra
 Regeneration → Example: Planaria, Hydra


 Sexual Reproduction (Human)


 Human being is heterosexual.
 Reproductive system includes:
 Primary sex organs: Testes (males) and ovaries (females)
 Secondary sex organs: Genital ducts and glands (males) and fallopian tubes,
uterus, vagina (females)
 Male sex hormone is testosterone and female sex hormones are
progesterone and estrogen.
 Puberty is attained at the age of 13 – 14 years in males and 10 – 12 years
 The zygote formed after fertilization develops into embryo which gets
implanted in uterus.
 Placenta (a disc-like special tissue) develops between uterine wall and
embryo for nourishment of the embryo.
 Gestation period in humans is 280 days.



 Reproductive Health


 Birth control prevents unwanted pregnancies.
 Barrier methods
 Chemical methods
 Intrauterine contraceptive device
 Surgical method
 Sexually transmitted diseases (STD) are caused by bacteria, protozoa and viruses.
 AIDS is an incurable viral disease.