CBSE Class 10 Science How Do Organisms Reproduce Notes Set 05

HOW DO ORGANISMS REPRODUCE

• Reproduction is the biological process by which living organisms produce new individuals (Offspring) similar to themselves.

• It ensures continuity species generation of generation.

Content:
Reproduction in animals and plants (asexual and sexual), Reproductive health - need and methods of family planning, Safe sex vs HIV/AIDS, Child bearing and women‘s health

TYPES OF REPRODUCTION

1- Asexual reproduction
2- Sexual reproduction

ASEXUAL REPRODUCTION AND VEGETATIVE REPRODUCTION

Fission
In this organism divide two or more equal part and each develops into identical new individuals. Ex. Amoeba

Regeneration
If an individual's body is cut into several pieces, each of its parts regrows into a new individual. Ex- Planaria

Budding
In this new organism develops on the bud (outgrowth on the parent body). The new organism remains attached to the parent body till it gets matures. Ex- Hydra, Yeast

Adventitious Bud
Small buds in the notches of the leaf. These have the ability to grow into new individuals. Ex – Bryophyllum

Spore formation
Spores are propagules produced in sporangia and germinate to produce new individuals. Rg. Rhizopus (bread mould)

SEXUAL REPRODUCTION

The sexual life cycle can be grouped into –

• i- Pre-reproductive phase- development to attain sexual maturity (puberty)
• ii- Reproductive phase- sexually mature, able to reproduce, able to produce fertile gametes
• iii- Post reproductive phase- after fertilization, development of embryo into new individual

SEXUAL REPRODUCTION IN FLOWERING PLANTS

• Reproductive part of pant is flower. Flower consists sepals, petals, stamens and carpels.
• Stamen and carpel contain anther and over respectively.
• Anther produces male gamete pollen and ovary contains female gamete egg.
• After pollination pollen fuses with egg to for zygote.
• Zygote develops in embryo and within ovule.
• Ovule develops into seed that contains future plant and ovary ripens in fruit.

REPRODUCTION IN HUMAN BEINGS

Male reproductive system –

• It consists of one pair of testes where sperm formation takes place.
• Testes also secrete hormones like testosterone.
• Testosterone brings about changes inthe appearance of boys at the time of puberty.
• Sperm is delivered through the vas deferens where secretions of the prostate gland and seminal vesicles add their secretions. These secretions help in transportation and provide nutrition to sperm.

Female reproductive system

• It consists of mainly a pair of ovaries and a uterus.
• On puberty the ovary starts producing eggs and releases one egg each month.

Fertilization

• Fertilization is a fusion of sperm and egg. It takes place in the fallopian tube. The fertilized egg is called a zygote which develops into an embryo.
• Uterus is for implantation purposes which hold the developing embryo in its layer through the placenta and umbilical card.
• When egg is not fertilized the inner lining of uterus breaks and comes out through the vagina as blood and mucus (menses). This cycle repeats every month and is called menstrual cycle.

REPRODUCTIVE HEALTH

STDs (Sexually transmitted diseases)- Spread from infected person to healthy person due to unprotected sex. E.g.- HIV-AIDS, Gonorrhea, Syphilis, and Warts.

Population control methods

• Mechanical barrier- Condom
• Hormonal methods- Pills
• Chemical method- Cut, Loops
• Surgical method- Vasectomy and Tubectomy