Lesson 3 Increasing agricultural yields Selective breeding (1).pptx

environmental management lesson on agriculture

1. 3.4 Mechanisation , selective breeding, GMO and controlled environments Chapter 3 pg 66-67

2. Learning Objectives: Keywords: Mechanisation Selective breeding Genetically modified organism (GMO) Core: Identify the methods used to increase agricultural yields. Extended: Describe the importance of mechanisation , selective breeding, GMO and controlled environments to increase agricultural yield. Challenge: Challenge: Research ow IR8 strain of rice averted the famine in  india   3.4 Increasing agricultural yields

3. Syllabus points

4. Starter: unscramble the keywords:

5. MECHANISATION

6. Selective breeding Selective breeding means to select individuals with desirable characteristics and breed them together. The process doesn’t stop there though because it’s likely that not all of the offspring will show the characteristics you want so offspring that do show the desired characteristics are selected and bred together. This process has to be repeated for many successive generations before you can definitely say you have a ‘new breed’ which will reliably show those selected characteristics in all offspring

7. Selective breeding in plants Plants are selectively bred by humans for development of many characteristics, including: Disease resistance in food crops Increased crop yield Hardiness to weather conditions (eg. drought tolerance) Better tasting fruits Large or unusual flowers An example of a plant that has been selectively bred in multiple ways is wild brassica, which has given rise to cauliflower, cabbage, broccoli, brussel sprouts, kale and kohlrabi:

8. Selective breeding in plants https://www.youtube.com/watch?v=3B4LEssKSLs

9. Selective breeding in animals Individuals with the characteristics you want are bred together (often several different parents all with the desired characteristics are chosen so siblings do not have to be bred together in the next generation). Offspring that show the desired characteristics are selected and bred together This process is repeated for many successive generations before you can definitely say you have a ‘new breed’ which will reliably show those selected characteristics in all offspring.

10. Animals are commonly selectively bred for various characteristics, including: Cows, goats and sheep that produce lots of milk or meat Chickens that lay large eggs Domestic dogs that have a gentle nature Sheep with good quality wool Horses with fine features and a very fast pace. An example of an animal that has been selectively bred by humans in many ways to produce breeds with many different characteristics is the domestic dog, all breeds of which are descended from wolves Selective breeding in animals

11. Task 1: List the steps involved in selective breeding in the correct order in your notebook Repeat the process Select the best offspring that show the desired characteristics Raise the offspring from these parents Choose the parents that exhibit these characteristics Identify which characteristics of the species are important 5 minutes

12. Crop plants, such as wheat and maize, have been genetically modified to contain a gene from a bacterium that produces a poison that kills insects, making them resistant to pests such as caterpillars. Crop plants have also been genetically modified to make them resistant to certain herbicides, so that when the herbicide is sprayed on the crop it only kills weeds and does not affect the crop plant. Some crops have been genetically modified to produce additional vitamins, eg ‘golden rice’ IR8 contains genes from another plant and a bacterium which make the rice grains produce a chemical that is turned into vitamin A in the human body, which helped in preventing a  deficiency diseases in certain areas of the world. Genetically modified organisms examples; https://www.youtube.com/watch?v=kZIYkYNpnP0 5 minutes

13. Task 2: list the Advantages & disadvantages of GM crops It is now possible to transfer genetic material between species of plants or animals. Not only breeds of the same species, the resulting organism is said to be transgenic.

14. Controlled environments: Greenhouses are structures that support the controlled growth of plants.

15. Growing plants without soil Soil is very variable which means that farmers may need to make large modifications to make it an ideal growing environment. At a large scale this is quite expensive. Scientists have developed a method to to grow plants without the need for soil, this method grows plants with water and nutrient and is called hydroponics.

16. Hydroponics https://www.youtube.com/watch?v=tzBK4QZSQaY 5 minutes

17. Hydroponics advantages No need for soil Can be used anywhere (there are experiments being carried out in space). an intensive system that can provide high yields. Easy to harvest. Nutrients given are in exact quantities. Water is recycled, so used efficiently.  No weeds or pests and diseases in the soil. Pollutants are not released into the environment.

18. Hydroponics disadvantages Expensive to set up. Only suitable for small production areas. Requires a lot of technical knowledge. Disease, if present, is rapidly spread through the water supply to all plants. Plants can die quickly if conditions are not maintained at optimum levels.

19. plenary: past-paper check 5 minutes

20. Learning Objectives: Keywords: Mechanisation Selective breeding Genetically modified organism (GMO) Core: Identify the methods used to increase agricultural yields. Extended: Describe the importance of mechanisation , selective breeding, GMO and controlled environments to increase agricultural yield. Challenge: Research ow IR8 strain of rice averted the famine in india   3.4 Increasing agricultural yields