Diversity in Living Organisms
1. Reproduction
The production of new organisms from existing organisms of the same species is known as reproduction.
2. Asexual Reproduction
Modes of asexual reproduction used are:
- Binary fission
- Multiple fission
- Budding
- Spore formation
- Regeneration
- Vegetative propagation
- Tissue culture
- Fragmentation
3. Sexual Reproduction
In sexual reproduction, a male gamete (germ cell) fuses with a female gamete to form a new cell called a zygote, which develops into a new organism.
Fertilization is of two types:
- External fertilization
- Internal fertilization
4. Sexual Reproduction in Flowering Plants
The flower is meant essentially for sexual reproduction.
- Pollination is the process in which pollen grains are transferred from the anther to the stigma of the carpel. It is of two types: self-pollination and cross-pollination.
- In the fertilization process, the primary endospermic nucleus is formed.
- After fertilization, the ovary develops into the fruit, whereas ovules develop into the seed.
5. Reproduction in Humans
The sex organs in males are testes, and in females, ovaries.
Male reproductive organs:
- Testes
- Vas deferens
- Epididymis
- Ejaculatory duct
- Urethra
- Accessory glands
Female reproductive organs:
- Ovaries
- Fallopian tubes
- Uterus
- Vagina
- Mammary glands
- Accessory glands
6. Reproductive Health – Barrier Methods
Different contraceptive methods include:
- Mechanical barrier method: Condom, cervical cap, diaphragm, IUCD.
- Hormonal method: Oral pills, implants, morning-after pills.
- Chemical contraception: Creams, jellies, and foaming tablets that kill sperm.
- Surgical techniques:
- Vasectomy: Blocking the vas deferens to prevent sperm passage.
- Tubectomy: Blocking the fallopian tubes to prevent ovum passage.
7. Sexually Transmitted Diseases (STDs)
STDs are infections transmitted through sexual contact. Some common examples include:
- Gonorrhoea
- Syphilis
- Trichomonas
- Genital warts
- AIDS