Revision Guide
This chapter explores the various methods of reproduction in organisms, including asexual and sexual reproduction, and the importance of reproduction in maintaining species continuity.
How do Organisms Reproduce? - Quick Look Revision Guide
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Key Points
Define reproduction and its importance.
Reproduction is the biological process by which new individual organisms are produced. It's essential for species survival, not individual survival, ensuring genetic continuity.
Explain DNA copying in reproduction.
DNA copying is crucial for inheritance, creating variations. Errors in copying lead to variations, some beneficial for species survival.
Describe binary fission in Amoeba.
Amoeba reproduces by splitting into two equal halves. It's a simple asexual method, showing no genetic variation.
What is multiple fission in Plasmodium?
Plasmodium divides into many daughter cells simultaneously. This method is efficient in harsh conditions, ensuring survival.
Explain budding in Hydra.
Hydra develops buds that grow into new individuals. It's asexual, producing clones of the parent.
Define vegetative propagation with examples.
Plants reproduce from roots, stems, leaves. Examples: potato (stem), Bryophyllum (leaf). It's faster and genetically identical.
What is spore formation in Rhizopus?
Rhizopus forms spores in sporangia. Spores are resistant, dispersing to grow into new organisms under favorable conditions.
Compare asexual and sexual reproduction.
Asexual: single parent, no variation. Sexual: two parents, genetic variation, beneficial for evolution.
Explain the importance of variation.
Variation ensures species survival in changing environments. It's the basis for evolution and adaptation.
Describe sexual reproduction in flowering plants.
Involves pollen transfer (pollination) to stigma, leading to fertilization. Results in seed formation, ensuring genetic diversity.
What are the male and female reproductive parts in flowers?
Male: stamen (anther, filament). Female: pistil (stigma, style, ovary). They facilitate pollination and fertilization.
Define pollination and its types.
Pollination is pollen transfer to stigma. Types: self (same flower), cross (different flowers). Agents: wind, water, animals.
Explain fertilization in plants.
Pollen tube delivers sperm to ovule. Sperm fuses with egg, forming zygote. Develops into embryo, leading to seed formation.
What changes occur during puberty?
Puberty brings sexual maturity: boys (facial hair, voice change), girls (breast development, menstruation). Hormones drive these changes.
Describe the male reproductive system.
Includes testes (sperm production), vas deferens, seminal vesicles, prostate, urethra. Testosterone regulates sperm production and male traits.
Describe the female reproductive system.
Includes ovaries (egg production), fallopian tubes, uterus, vagina. Estrogen regulates egg production and female traits.
Explain menstruation and its cycle.
Monthly shedding of uterine lining if no fertilization. Cycle: ~28 days, involves egg release, lining preparation, and shedding.
What is the role of placenta?
Placenta nourishes the embryo, supplying oxygen, nutrients from mother's blood, and removing wastes. It's vital for fetal development.
List contraceptive methods and their importance.
Methods: condoms, pills, copper-T, surgery. Prevent pregnancy, STDs. Essential for family planning and health.
Why is sex ratio important?
Balanced sex ratio ensures healthy society. Female foeticide disrupts balance, leading to social issues. Laws prohibit sex determination.
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