4. Describe the main events of the menstrual cycle.
Reproduction in Humans 13 L
5. Explain what is meant by the fertile period. 6. Identify the structures L and M in the diagram.
L ______________________ M ______________________
7. Describe the effect of implantation on the menstrual cycle.
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Thinking and Investigating 1. Ovulation normally occurs on day 14 of the menstrual cycle and the egg normally only
survives for one or two days, yet the fertile period lasts for about six days. Find out about the survival time for sperm and use this information to explain why the fertile period includes a number of days before and after ovulation.
2. Fertilisation occurs in the fallopian tube. For fertilisation to occur, sperm must swim through the uterus into the fallopian tube. After fertilisation, the zygote moves through the fallopian tube and into the uterus. Why do you think that fertilisation does not just take place in the uterus?
3. The average time taken for a baby to develop from the time of ovulation to the time of birth is 38 weeks. However, the length of pregnancy is considered to be 40 weeks. What do you think the measurement of 40 weeks is based on? Why is it important to know the duration of pregnancy?
4. The process of childbirth is often divided into three stages. Find out what these three stages are. Outline the main events of each stage.
5. A fertilised egg is a zygote. Identical twins are monozygotic while non-identical twins are dizygotic. What do you think that these terms mean? Non-identical twins are not always the same sex as each other while identical twins are. Explain.
6. The ‘one-child policy’ was in place in China from 1980 until 2015. Why do you think that the Chinese government wanted to reduce population growth? Why do you think that couples in rural areas were allowed to have more children than those in urban areas? Do you think that a policy like this would be good for society? What are some of the issues that this policy would raise for families and for society as a whole?
