1. © OUP: To be used solely in purchaser’s school or college 9A Inheritance and selection Inheritance Variation 9A Inheritance and selection Selective breeding

2. © OUP: To be used solely in purchaser’s school or college 9A Inheritance and selection Inheritance

3. © OUP: To be used solely in purchaser’s school or college 9A With love from Mum and Dad You are similar to both your mother and your father. But why? sperm from your father Both the sperm and the egg carry genes. These control how your body grows and develops. Where in the cells are the genes? ovum (egg) from your mother

4. © OUP: To be used solely in purchaser’s school or college 9A Eggs, sperm, twins and genes Why do identical twins have the same genes?

5. © OUP: To be used solely in purchaser’s school or college 1. Some identical twins have different fathers.2. Identical twins can donate organs to each other and their bodies will not reject the transplanted organs. 3. Because they have the same genes, identical twins are telepathic (they can read each other’s minds). 4. Identical twins always have the same blood group.5. Amy has brown eyes but her identical twin Billie has blue eyes. True or False? 9A Twin study To be identical they must both have come from one sperm and one egg. FALSE! Because identical twins are genetically the same. TRUE!Perhaps they can guess what the other is thinking because they know each other so well, but genes can’t make you telepathic. FALSE!Blood group is an inherited characteristic. TRUE! That’s just twin twaddle!FALSE!

6. © OUP: To be used solely in purchaser’s school or college Is each characteristic inherited, environmental or both? skin colour large ear lobes mass at age 21 mass at birth scar on left knee can run very fast height blood group A green eyes BothEnvironmentalInherited 9A Inherited, environmental or both?

7. © OUP: To be used solely in purchaser’s school or college 9A Plant sex! Like animals, plants pass on their genes when they reproduce. The sex cells, or gametes, combine at fertilisation. The sperm is the male gamete in humans. What’s the male gamete in flowering plants? What’s the female gamete in humans? And in flowering plants?

8. © OUP: To be used solely in purchaser’s school or college 9A Pollination Wind or insects carry pollen from one flower to another for pollination. What carries the pollen from each of the flowers shown below? How can you tell? For the gametes to fuse at fertilisation, the pollen must find the egg cell.

9. © OUP: To be used solely in purchaser’s school or college 9A Fertilisation in flowering plants stigma style ovary egg cell ovule Pollination – the pollen arrives at the stigma. How do the gametes fuse to combine the genes in flowering plants? A pollen tube grows down the style from the pollen grain. The pollen tube reaches the ovule, carrying the pollen nucleus. The pollen nucleus reaches the egg cell. They fuse – fertilisation. The seed that grows contains genes from both the pollen grain and the egg cell.

10. © OUP: To be used solely in purchaser’s school or college Sex is really the same thing in plants and animals! 9A Plant and animal sex... Fill in the boxes for humans and flowering plants. The nuclei of the gametes carry genes. The new life has genes from both parents. sexual intercourse egg pollensperm It grows to form a Fertilised egg is called a Gametes fuse during Male gamete transferred by Female gamete Male gamete flowering plantshumans pollination fertilisation zygote fetusseed

11. © OUP: To be used solely in purchaser’s school or college Variation 9A Inheritance and selection

12. © OUP: To be used solely in purchaser’s school or college 9A Everybody’s different … and the same! Humans are all the same species. What does that mean? But we are all slightly different. Variation is differences between organisms in the same species. Give 5 differences you can see in this picture. Is this variation inherited, environmental or both?

13. © OUP: To be used solely in purchaser’s school or college 9A Variation or not? Give 3 differences between an apple and a starfish. Would you use the word variation for these differences? Give 3 differences between a sheepdog and a terrier. Is this variation?

14. © OUP: To be used solely in purchaser’s school or college 1. A tall plant and a short one.2. People with different coloured eyes.3. The fitness of an athlete and a couch potato.4. People with different shoe sizes.5. Beetles of different masses.6. Beetles with different numbers of spots. Suggest ways to measure variation between... 9A How do we measure variation? Measure the height of each plant with a tape measure or metre rule. ANSWER Just look at the eyes and note down the colour for each person. ANSWERMeasure their heart rate after exercise, or how long they took to run 100 metres. ANSWERAsk their shoe sizes and note them down for each person. ANSWERMeasure the mass of each beetle with a balance. ANSWERLook at the beetles and note down how many spots each one has. ANSWER

15. © OUP: To be used solely in purchaser’s school or college 9A Discontinuous variation All Man. United fans please stand up! Sit down. Now people who have a J in their first name stand up. Sit down. Stand up if you have an older brother. OK sit down. Stand up if you are female. Sit down. People whose favourite subject is science, stand up. OK, you can all sit down now!

16. © OUP: To be used solely in purchaser’s school or college 9A What is discontinuous variation? In discontinuous variation, all the possibilities fit into neat classes – ‘yes’ or ‘no’; ‘2 spots’ or ‘3 spots’. You either do have a J in your first name, or you don’t. (You can’t have half a J!) We often show discontinuous variation on a bar chart. Can you think of some more examples? blood group number of people ABOAB beetle spots number of beetles 1 spot 2 spots 3 spots 4 spots 5 spots

17. © OUP: To be used solely in purchaser’s school or college 9A Continuous variation Every year they have a glamorous granny competition at this holiday camp. And the winner this year is … Doris, who is 175 cm tall and has four lovely grandchildren. 184cm 172cm 169cm 166cm 177cm 175cm

18. © OUP: To be used solely in purchaser’s school or college 9A What is continuous variation? In continuous variation, there is a range of possible results. We usually have to measure something. The grannies had a range of heights. We use a line graph to show continuous variation. Suggest some more examples of continuous variation. hand spans of 9X hand span (cm) 15161718 number of people heights of glamorous grannies height (cm) 160170180 few short people lots of middle-sized people few tall people number of people

19. © OUP: To be used solely in purchaser’s school or college 9A Continuous or discontinuous? Do these features show continuous or discontinuous variation? Do they show inherited or environmental variation? skin colour blood group length of little finger body mass height sex (male or female) eye colour

20. © OUP: To be used solely in purchaser’s school or college Selective breeding 9A Inheritance and selection

21. © OUP: To be used solely in purchaser’s school or college 9A Breeding for the best Human beings have been breeding plants and animals for thousands of years. Farmers picked the best milk cows to produce calves, so that they would inherit their milk-producing genes. Other farmers collected seeds from the best wheat plants, so that the next generation would also be good plants. But what do we mean by ‘best’ and ‘good’?

22. © OUP: To be used solely in purchaser’s school or college 9A Choose a cow!

23. © OUP: To be used solely in purchaser’s school or college Selective breeding allows modern farmers to grow just a few good varieties. 9A Are we losing our vegetables? What is the overall trend? Why do you think this is happening? What disadvantages might this bring? number of different varieties in 1903 number of different varieties in 1992 artichoke 34 2 asparagus 46 1 runner bean 14 1 garden bean57832 beetroot28817

24. © OUP: To be used solely in purchaser’s school or college 9A Plant-breeding techniques Anne the plant breeder chooses two parent plants with useful characteristics. One plant will be the female parent. Anne removes the anthers and covers the flower with a bag. Why? She puts the bag over the flower again. Later she collects the seeds and grows them to produce the new plant. female parent anthers removed collected pollen The other plant is the male parent. Its anthers develop as normal. Anne collects its pollen and brushes it onto the female plant.

25. © OUP: To be used solely in purchaser’s school or college 9A Quick Quiz 1. What do we call reproduction when one parent produces offspring with the same genes as the parent? a) Unusual reproduction b) Asexual reproduction c) Unsexual reproduction. 2. Clones can be described as… a) organisms with different genes b) organisms with the same genes c) organisms with denim jeans.