Table of contents |
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What is Reproduction? |
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Lifespan |
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Modes of Reproduction |
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Events in Sexual Reproduction |
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Reproduction is a biological process of the formation of new offsprings from the pre-existing organism.
Reproduction becomes a vital process without which species cannot survive for long. It ensures continuity of species generation after generation as older individuals undergo senescence and ultimately they die.
The period from birth to the natural death of an organism represents its lifespan. The lifespan of organisms varies from a few days (Butterfly-1 to 2 weeks) to thousands of years (Banyan tree).
The lifespan of a human
Based on whether there are one or two organisms taking part in the process of reproduction.
Classification of Asexual Reproduction
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Modes of Reproduction: Asexual & Sexual
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Following are the advantages of asexual reproduction:
The major disadvantages of asexual reproduction are:
Phases of Life
1. Juvenile Phase/Vegetative Phase
2. Reproductive Phase
(i) Menstrual Cycle: It occurs in monkeys, apes and human beings.
(ii) Oestrous Cycle: It occurs in non-primates like cow, sheep, rat, deer, dog, tiger etc.
3. Senescent Phase:
All the events prior to the fusion of gametes are included in it.
It includes gametogenesis and gamete transfer:
(i) Gametogenesis
(ii) Gamete Transfer
Fetal development from ovulation to implantation
(i) The Zygote
(ii) Embryogenesis
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1. What is reproduction? | ![]() |
2. What is the lifespan of an individual organism? | ![]() |
3. What are the modes of reproduction? | ![]() |
4. What are the events involved in sexual reproduction? | ![]() |
5. What are the advantages and disadvantages of asexual and sexual reproduction? | ![]() |