Fertilization, a fundamental process for sexual reproduction, occurs through two primary mechanisms. These mechanisms differ based on where the egg and sperm unite.
According to the provided reference, the two types of fertilization are:
- External Fertilization: The union of egg and sperm occurs outside the female's body.
- Internal Fertilization: The union of egg and sperm occurs inside the female's reproductive tract.
Here's a more detailed look:
External Fertilization
- Definition: In external fertilization, the female releases eggs into the environment, and the male fertilizes them outside of her body.
- Environment: Typically occurs in aquatic environments to facilitate sperm movement.
- Examples: Common in fish and amphibians.
- Advantages: Can result in a large number of offspring.
- Disadvantages: Eggs and sperm are vulnerable to predators and environmental hazards, leading to lower survival rates.
Internal Fertilization
- Definition: In internal fertilization, the sperm fertilizes the egg inside the female's body.
- Environment: Primarily occurs in terrestrial animals.
- Examples: Seen in reptiles, birds, and mammals.
- Advantages: Provides a more protected environment for the developing embryo, increasing survival rates.
- Disadvantages: Typically results in fewer offspring compared to external fertilization.
The following table summarizes the key differences:
| Feature | External Fertilization | Internal Fertilization |
|---|---|---|
| Location | Outside the female's body | Inside the female's body |
| Common In | Fish, Amphibians | Reptiles, Birds, Mammals |
| Environment | Aquatic | Terrestrial |
| Offspring Number | Generally High | Generally Low |
| Embryo Protection | Low | High |
