Reproduction and Development
This lesson teaches students about reproduction and embryo development.
• To be able to explain internal and external fertilization.
To be able to list the stages of an embryo.
To be able to identify the organs and terms used regarding reproduction.
Some animals that are simpler have both sperm-making and egg-making organs in their bodies. For example, earthworms have both of these organs in their bodies. While this is the case for some animals, most animals make male and females gametes separately. Most animals have separate male and female creatures that make these gametes.
There are different types of fertilization. If sperm and an egg are joined outside of the parents? bodies, the process is called external fertilization. If sperm and an egg are joined inside of the female?s body, the process is called internal fertilization.