So What Do You Think Today’s Lesson Is About? AP Biology Tuesday 10/7/14

Objectives Level 6 EXPLAIN Produce the best cow by selective breeding. Level 5 PRODUCE Explain which cows you needed to breed with which bulls to get the best offspring. Level 7 EVALUATE Describe the advantages and disadvantages of selective breeding

What features would you choose from these dogs to make an ideal dog of YOUR choice

Gamekeepers in the 1800s had a problem. Poachers were entering their land and stealing their game-birds before the shooting season. Their dogs (mastiffs) were big, strong dogs and great companions but they were not aggressive or fast enough to chase after the poachers. Mastiff Bulldog Another breed known to them was the bulldog. This was quick and aggressive but not strong enough to pull the poachers down and hold them until a gamekeeper arrived. What could they do?

Humans have changed the way dogs look and act by choosing which dogs to breed together. Mastiff – large and strong but slow and not aggressive. Bulldog – Aggressive and quick but small. Bullmastiff – Large, quick, strong and aggressive This is called Selective Breeding Perfect! +

This dog is a more modern example of selective breeding. It is a relatively new breed called a labradoodle. What two dogs do you think were bred to make it?

Modern Selective Breeding  Traditionally, selective breeding was the selection of two likely parents and then breeding the two together.  Modern scientific advances have made it possible to be even more precise.

 Plants can now be grown from fragments of another – this is called cloning.  Not only do you know what the new plants will look like, it is also quicker than waiting for seeds to form and then grow.

 Breeding farm animals traditionally involved putting the two parent animals together. This could be dangerous and could involve transporting livestock long distances.

 Nowadays, sperm and eggs can be transported instead of the whole animal.  This is far more convenient.  Sperm and eggs can even be cold-stored until needed.

 Selected mother cattle can then be artificially inseminated with stored sperm.  This is safer than handling a bull!

 Going one step further still, sperm and egg can be obtained from the parents. They are then combined in the lab to produce developing embryos.

 All pigs have been selectively bred from the wild boar.  They are now:  less aggressive so easier to farm  longer to produce more meat  less hairy so they make better scratchings.

 Food production has been greatly increased by selective breeding.  It is an example of artificial selection.