1. Selective Breeding Noadswood Science, 2012

2. Selective Breeding  What do you understand by the term ‘selective breeding’?

3. Natural Selection  Species gradually evolve by a process of natural selection  Individuals in a species show a wide variation (due to gene differences)  Individuals with inherited features best suited to their environment are most likely to survive and reproduce: passing on their genetic information to their offspring

4. Natural Selection  Over time, a species can change its appearance, and may even become a new species, unable to reproduce successfully with individuals of the original species  Individuals with the most favourable genes for the environment they live in are selected over time: this is natural selection

5. Selective Breeding  To understand the importance of selective breeding Friday, October 09, 2015

6. Selective Breeding  Selective breeding is a process used to produce different breeds of animals or varieties of plants that have useful characteristics  Using selective breeding you can produce a specific offspring with useful characteristics of both parents  What organisms do farmers ‘selectively breed’?

7. Selective Breeding  Farmers can choose individual cows to mate in order to produce a generation of cows that will yield more milk  Farmers could also selectively breed for docile animals  Apple growers want to produce a type of apple that is tasty and resistant to disease. This can be done by crossing a variety of apple known for taste with another variety that shows strong resistance to disease  Farmers could also selectively breed for crops of a uniform height / when they are ready for harvest

8. Animals  To selectively breed animals often a ‘stud’ male is used to breed.  Artificial insemination is also used (where a vet will deliberately introduce semen into the female)

9. E.g. Cows  Suppose you wanted a variety of cow that produced a lot of milk: -  Choose or select the cows in your herd that produce the most milk  Only let these cows reproduce  Select the offspring that produce the most milk  Only let these offspring reproduce  Keep repeating the process of selection and breeding until you achieve your goal

10. Perfect Pet  Imagine you wanted to create your perfect dog – how would you selectively breed for it?  What two parents are you going to choose?  What qualities do each of them have (which you want)  How are you going to ‘get’ these qualities in your pet?  Draw out and annotate creating your perfect dog…

11. Dog Parents

12. Labradoodle  Look at the following dogs - crossing a Poodle and a Labrador results in a ‘Labradoodle’  What features has the Labradoodle inherited from the Labrador?  What features has the Labradoodle inherited from the Poodle? PoodleLabrador Labradoodle + +

13.  The Labradoodle is large (like the Labrador), has a fluffy coat (like the Poodle) which sheds much less than a Labrador’s coat. They are also generally well tempered and good swimmers (like both its parents breeds).  So the Labradoodle has favourable characteristics from both of its parents breeds PoodleLabrador Labradoodle + +

14. Summary  The key is to identify the feature you want, and only breed from the individuals that have that feature – it is achieved by…  Select parents with the desired traits (things you want)  Cross the parents (breed them)  Select from the offspring  Repeat (over many generations)…  Selective breeding is used to: -  Choose characteristics of the food item required  Produce a more uniform crop (size / harvest time)  Extend the tolerance range of an organism