3.19b F1 x F1 Cross

3.19a P1 x P1 Cross

3.18b Genotypes

3.18a Phenotypes

3.2 Fertilisation

• The adult male and female gametes are formed by meiosis. 
• When we have sufficient cells this will then be called an embryo.
• The cells that are formed by meiosis have half as many chromosomes as the cell that formed them.
• Fertilisation occurs when a male and female gamete join.
• The zygote divides into a ball of cells, called the blastula which then grows to form the embryo.

3.9a Male reproduction system

• Urine is stored in the bladder.
• The penis carries the sperm into the vagina.
• Sperm is stored in the epididymis.
• The seminal vesticle produces 70% of the semen.
• Urethra is the tube which connects the testes and the SV which takes semen to the penis.