Sexual Reproduction

key notes:

Definition of Sexual Reproduction:

• Sexual reproduction is a biological process that involves the fusion of male and female gametes (sperm and egg), leading to the formation of offspring with genetic material from both parents.

Gametes:

• Male Gamete (Sperm): Produced by the male reproductive organs (testes).
• Female Gamete (Egg/Ovum): Produced by the female reproductive organs (ovaries).

Fertilization:

• Internal Fertilization: Fusion of sperm and egg happens inside the female body (e.g., humans, mammals, birds).
• External Fertilization: Fertilization occurs outside the body, usually in water (e.g., fish, amphibians).

Zygote Formation:

• The fertilized egg is called a zygote, which undergoes cell division and develops into an embryo.

Development of Embryo:

• The zygote divides repeatedly to form a multicellular structure called an embryo.
• The embryo further develops into a fetus in animals with internal fertilization.

Types of Animals Based on Fertilization:

• Oviparous Animals: Animals that lay eggs (e.g., birds, reptiles).
• Viviparous Animals: Animals that give birth to live young (e.g., mammals).

Sexual Dimorphism:

• Many animals exhibit sexual dimorphism, where males and females have different physical characteristics, apart from reproductive organs.

Advantages of Sexual Reproduction:

• Produces genetically diverse offspring, increasing the chances of survival in changing environments.

Examples of Sexual Reproduction:

• Humans, lions, birds, and frogs all reproduce sexually, with distinct reproductive organs and processes of fertilization.

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