Let s recap from last time!

Transcription

1 Selective Breeding

2 Let s recap from last time! Natural selection - The process by which individuals that are better adapted to the environment survive and reproduce more successfully than other members of their species These adaptations are incredibly varied

3 Examples: Counter shading in fish Bird beaks

4 Where we come in Human Intervention

5 Selective Breeding Scientists pick out the best traits in organisms to create the species they prefer. Selective breeding is the process of breeding plants and animals for particular genetic traits. Domestic animals are commonly bred for various traits. *Domestic animal: animal that has been tamed and kept by humans for work, food or as a pet.

6 Selective Breeding - Dogs Dogs are bred for many reasons such as their intelligence, trainability, and good looks

7 Selective Breeding - Livestock Longhorn Cattle Good trail cattle, lean meat Hereford Cattle Good beef

8 Selective Breeding - Food Crops

9 Selective Breeding - Flowers

10 Selective Breeding - Bees Africanized honey bees high productivity

11 Problems with Selective Breeding undesirable traits Hip Dysplasia in dogs Purebreds are more prone to this disease than cross-breeds (mutts) Inbreeding encourages negative traits the gene pool is less diverse Hip dysplasia is common in: Saint Bernard Great Danes Labs German Shepherd and more

12 Problems in Selective Breeding WHITE GREAT DANES DEAFNESS AND EYE ANOMALIES

13 Problems in Selective Breeding Africanized honey bees, known as "killer bees," are hybrids of the African honey bee with various European honey bees - bred for their high productivity accidentally released from an apiary Brazil in 1957 far more aggressive than the European subspecies 500 bee stings are equivalent to a rattlesnake bite

14 Back to dogs: Dogs belong to a single species, Canis familiaris, but that species is comprised of about 400 different breeds. Since they are a single species, they can mate and have viable offspring. Recognized dog breeds take generations to establish through selective breeding or artificial selection. Many of the breeds we have today are the result of people's desire to have dogs with specific features that make them suitable for performing particular tasks, such as retrieving, protection, assistance, hunting, and companionship, to name just a few. The process of breeding a new type of dog often involves identifying desired features, finding dogs with those features, then performing a series of matings to produce offspring with the appropriate combination of traits. After a number of generations, a new breed may be established.

15 Activity Selective Breeding of Dogs You will begin by examining canine features and their functions. Then you will be given a scenario that describes the type of task they need a new breed of dog to perform. Then select two existing breeds that will most likely produce a successful new breed and determine the resulting offspring's characteristics.

16 "How to Get an American Foxhound and Why" What are your thoughts?

17 "How to Get an American Foxhound and Why" The American Foxhound is half descended from the English Foxhounds that were brought to America in The English hounds were crossed with a French hound. The combination breed became an excellent hunter of wild animals. The American Foxhound has great speed and an excellent sense of smell. It can run at high speed for long periods and has a musical bay that is easy to follow. American Foxhounds are still used as hunting dogs today but are also used as companions and watchdogs.

18 Dog Breeds Describe the features or abilities of dogs for which humans might breed. It is possible to select dogs to breed for particular traits because all dogs are from the same species, Canis familiaris. The various breeds can mate with each other to produce offspring. Most breeds today are a result of artificial or selective breeding

19 Let s make a dog breed! I will put up pictures and we need to identify which traits would match what we are looking for

20 Which traits? We did a dog to hear a polar bear and then alarm the bear

21 What did we pick? Pointed ears are good for hearing and a loud bark will travel a longer distance. Long fur will help the dogs stay warmer out in the cold. Which traits are probably not very important? (eye color). Which breeds would probably be best to cross? (Breed 1 and Breed 3)

22 Physical Traits Physical traits serve a very specific function for dogs. Each of these could play an important role, or have significance for humans when they need a dog to perform a particular function.

23 Discussion question How has selective breeding impacted scientific thought and society?

24 Artificial Selection