Sexual Reproduction Involves The Fusion of Two Distinct Gametes
- The two distinct gametes: sperm (male) and egg (female), creates a zygote, the first cell of a new organism.

Zygote
A eukaryotic cell formed by the fusion of two gametes.
- Think of sperm as the "messenger" and the egg as the "receiver"
- The sperm travels to deliver genetic information, while the egg provides the environment for development.
Key Differences Between Male and Female Gametes
1. Size and Structure
- Sperm: Small and streamlined, designed for mobility.
- Egg: Large and nutrient-rich, providing sustenance for the developing embryo.
2. Energy Reserves
- Sperm: Minimal energy reserves, designed for short-term function.
- Egg: Contains substantial reserves to support early embryonic development.
Don't assume that larger size always means greater complexity. The egg's size is primarily due to its nutrient content, not structural complexity.
3. Numbers Produced
- Sperm: Produced in large quantities (millions per day in humans).
- Eggs: Produced in limited numbers (one per menstrual cycle in humans).
- During ejaculation, a male releases approximately 200–300 million sperm.
- In contrast, a female typically releases one egg per cycle.
Reproductive Strategies: Males vs. Females
Males Prioritize Quantity Over Quality
- Quantity Over Quality: Produces vast numbers of sperm to increase the likelihood of fertilization.


