KEY STAGE 3 REPRODUCTION

1. KEY STAGE 3 REPRODUCTION

2. Reproduction What is reproduction? Reproduction is when organisms produce new living things. Plants and animals reproduce to make new individuals of the same species. What do you think might happen if organisms didn’t reproduce?

3. Asexual vs Sexual • Not all organisms reproduce like humans • do. In fact there are actually two • types of reproduction: • Asexual • Sexual

4. Asexual Reproduction In asexual reproduction there is only one parent. The new individual is genetically identical to its parent. Organisms can reproduce asexually in many different ways. e.g: • Some very small organisms can simply divide • into two e.g. bacteria • Some organisms can reproduce by ‘budding’. • A part of their body breaks off and grows into a • new organism. e.g some flowering plants

5. Sexual Reproduction Most animals reproduce sexually. In sexual reproduction there are two parents. The parents have sex organs which produce sex cells or gametes. The offspring of sexual reproduction are genetically quite different to their parents.

6. Activity Asexual or sexual? On the next slide is the names of eight different organisms. Drag their name to the correct table depending on whether you think that they carry out asexual or sexual reproduction. Think carefully!

7. Activity

8. A Bit of Both? Some organisms can carry out both sexual and asexual reproduction For example: Strawberry plants can reproduce by producing a miniature plant on a long shoot called a stolon. They can also produce new plants by sexual reproduction using flowers and seeds.

9. Human Reproduction Humans use sexual reproduction to produce their young. In order to do this the two parents have to have sex organs so that they can produce sex cells. In humans males and females have different reproductive systems and sex organs Go to the activity on the next page to see how much you know.

10. Activity Male or female On the next slide is the names of eight different parts of the male and female human reproductive systems. Drag their name to the correct table depending on whether you think that they are part of the male system or part of the female system. Do you really know as much as you think you do!

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12. The Male Reproductive System

13. The Female Reproductive System

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15. Nucleus containing chromosomes Cell membrane Head Tail Middle piece Sex cells - Sperm In males the sex cells are called sperm. Sperm are produced in sex organs called testes

16. Nucleus containing chromosomes cytoplasm membrane jelly coat An egg is so big that this is how big a sperm looks next to it. Sex cells - Eggs In females the sex cells are called eggs. Eggs are produced in sex organs called ovaries.

17. Both sperm and eggs have special features that makes it possible for them to carry out their jobs. Look at the statements on the next page and decide which one you think belongs to an egg and which one belongs to a sperm. Once you think you know push the buttons to see if you are right. Activity Sperm or Egg?

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19. Ovulation, and Fertilisation In the female one of the ovaries produces an egg every 28 days. This is called ovulation. During sexual intercourse sperm is ejaculated into the vagina. If the sperm and egg meet the sperms nucleus will join with the eggs nucleus. This is called fertilisation.

20. Fertilisation and Implantation

21. Activity Word Check

22. The Placenta How does the embryo get food and oxygen and get rid of waste? It forms a plate like structure called the placenta. The umbilical cord joins the foetus to the placenta. In the placenta food and oxygen diffuse from the mothers blood into the blood of the foetus. Carbon dioxide and waste products diffuse from the blood of the foetus to the mothers blood.

23. The Placenta

25. Activity Embryo Development

26. Activity Embryo Development

27. Birth

28. Puberty Human children are born with a complete set of sex organs. However they do not become active until later in life. Between 10 and 18 the testes start to make sperm and the ovaries start to make eggs. This time of development in their life is called PUBERTY. As well as these changes other changes may also occur.

29. Activity Puberty in Girls

30. Activity Puberty in Boys

31. Menstruation One change that happens to girls at puberty is that they start to undergo a monthly cycle called the menstrual cycle. This cycle is a process where the uterus lining builds up to receive a fertilised egg. If an egg is not fertilised then the lining of the uterus breaks down and is lost from the body. This is called menstruation or a period.

32. The Menstrual Cycle

33. Control of the menstrual cycle • A pituitary hormone called follicle stimulating hormone (FSH) stimulates follicle to develop. This causes the eggs to divide and grow. • The follicle secretes oestrogen. This causes the uterus to thicken. The oestrogen travel to the pituitary gland via blood to stop FSH production and produce luteinising hormone(LH) which stimulates ovulation and transforms follicles into a yellow body. • The yellow body makes progesterone which thickens the uterus lining for pregnancy.

34. Fertility Drugs • Often the cause of infertility in women is that ovaries do not release eggs. This is due to the lack of FSH. • Treatment: Injections containing FSH • Treatment: Tablets that makes pituitary insensitive to oestrogen. Why? • What if the man does not produce enough sperm? • AI: artificial insemination

35. Methods of birth control