Seed Reproduction

Sexual Reproduction is important in involution.

Evolution has to do with the belief that plants and animals change over time to adapt to their environment. in sexual reproduction there is a greater chance of change due to the offspring gets characteristics from two parents. In cloning, the offspring are identical to the parents.

Internal and External Fertilization

There are two mechanisms by which fertilization can take place. 
Internal Fertilization - In some animals  like humans and birds , the sperm fertilize the egg inside the female's body. This is called internal fertilization. Both male and female get close together so that the male can inject the sperm into the females body. This is called mating.

External Fertilization - In other animals , the male deposits the sperm on the eggs outside the body of the female. This is called external fertilization. For some fish and frogs , fertilization is external.

snails eggs

Sexual Reproduction

In sexual reproduction there are 2 biological parents.

The parents have sex organs. the sex organs make sex cells.

In animals, the mal sex cells are call sperm (spermatozoan). The sperm is made in the sex organs called testicles. In female animals the sex cells are called eggs or ovum. The ovum are made in the ovaries.

The sperm joins with the ovum to form a fertilized egg that will grow into a new organism.

When a sperm comes into contact with an egg, the nucleus of the sperm will fuse with the nucleus of the egg. This is called fertilization.