Fertilization is defined as the fusion of male gamete (sperm) with a female gamete (an ovum or egg) to form a zygote during sexual reproduction.
Two types of fertilization: External and Internal.
Two types of fertilization: External and Internal.
External fertilization vs Internal fertilization
External
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Internal fertilization
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The fusion of male gamete and female gamete occurs outside the body
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The fusion of gametes occurs inside the body.
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Both individuals discharge their gametes outside the body.
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Only male discharges sperms into female genital tract.
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Development occur outside the body.
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Development occurs inside the body.
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External fertilization occurs in Fish, Toads, and Frogs (Amphibians).
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Internal fertilization occurs in Human, cattle, Birds etc. The site of fertilization in human beings is in the fallopian tube of female reproductive system.
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Advantages and Disadvantages of Internal Fertilization and External fertilization
Internal fertilization Advantages: - More offspring survive due to protection of embryo and parental care.
- High chance of successful fertilization.
- Requires more energy to find a mate.
- less number of offspring produced.
- Large investment from female parent, may leave her vulnerable.
- Little energy needed to find a mate.
- Many offspring produced.
- Offspring not in competition with parents.
- Many gametes do not survive or are not fertilized.
- Zygotes and embryos are unprotected.
- No parental care mean many offspring do not survive to adulthood.