Focus on California Life Science 7th Grade Unit 2 - Interdisciplinary Exploration Dogs

Interdisciplinary Exploration Egyptian Art More than years ago , an artist drew three dogs chasing a hyena . Loyal Companions What your image of a dog ?

A powerful Great Dane ?

A tiny , lively Chihuahua ?

A protective German shepherd guide dog ?

A friendly , lovable mutt ?

Most dogs are descendants of the gray wolf , which was originally found throughout Europe , Asia , and North America . Dogs were the first animals to be domesticated , or tamed . As far back as years ago , farmers who raised sheep , cattle . and goats tamed dogs to herd and guard the livestock . Girl with dalmatian After taming dogs , people began to breed them for traits that people valued . Early herding dogs helped shepherds . Speedy hunting dogs learned to chase deer and other game . Strong . sturdy working dogs pulled sleds and even rescued people . Small , quick terriers hunted animals , such as rats . Toy dogs were companions to people of wealth and leisure . More recently , sporting dogs were trained to out and retrieve birds . Still others were bred to be guard dogs . But perhaps the real reasons people bred dogs were for loyalty and companionship .

From Wolf to Purebred About years ago , some wolves may have been attracted to human settlements . They may have found it easier to feed on food scraps than to hunt for themselves . Gradually the wolves came to depend on people for food . The wolves , in turn , kept the campsites clean and safe . They ate the garbage and barked to warn of approaching strangers . These wolves were the ancestors of the dogs you know today . Over time , dogs became more and more a part of human society . People began to breed dogs for the traits needed for tasks such as herding sheep and hunting . Large , aggressive dogs , for example , were bred to be herding dogs , while fast dogs with a keen sense of smell were bred to be hunting dogs . Today , there are Today , people breed dogs mostly for their appearance and personality . Physical features such as long ears or a narrow snout are valued in particular breeds of dogs . To create pure breeds of dogs . breeders use a method known as inbreeding . Inbreeding involves mating dogs that are genetically very similar . Inbreeding is the surest way to produce dogs with a uniform physical appearance . One undesirable result of inbreeding is an increase in genetic disorders . Experts estimate that 25 percent of all purebred dogs have a genetic disorder . Dalmatians , for example , often inherit deafness . German shepherds may develop severe hip problems . dogs . in contrast , are less likely to inherit genetic disorders . hundreds of breeds . They range from the tiny Chihuahua to the massive Saint Bernard , one of which can weigh as much as 50 Chihuahuas . Most traits that dogs are bred for are controlled by more than one gene . A few traits , however , show simpler inheritance patterns . For example , in Labrador , a single gene with one , dominant and one recessive allele determines whether the dog fur will be dark or yellow . The allele for dark fur ( is dominant over the allele for yellow fur ( Construct a square for a cross between two Labrador retrievers that are both heterozygous for dark fur ( Science Activity Fur Color in Retrievers In Labrador retrievers , the allele for fur is dominant over the allele for yellow fur . Suppose there were eight puppies in the litter . Predict how many would have dark fur and how many would have yellow fur . Construct a second square for a cross between a Labrador retriever with yellow fur ( and one with dark fur ( In a litter with six puppies , predict how many would have dark fur and how many would have yellow fur . 307

Social Studies Dogs and People Over thousands of years , people have developed many different breeds of dogs . Each of the dogs at shown on the map was bred for a hunting , herding , guarding , pulling well Bode i as companionship . Every breed has its own story , am , All 00 This breed was developed in the counties near the border between England and Scotland for herding sheep . The border collie ancestors were of local sheepdogs and dogs brought to Scotland by the Vikings Germany , AD . These dogs were bred to catch badgers or rats . Their short legs ' and long body can fit into a badgers burrow . In fact . in German the word Dachshund means badger dog . Golden Retriever Great Britain , AD . 1870 Lord developed this breed to help hunters retrieve waterfowl and other small ' France , AL . 15005 Second only to the . hound at following a scent , the basset hound has ' short legs and a compact . vi , body that help it run through underbrush . Greyhound 3000 ac . These speedy , slender hounds were bred for . chasing prey . Today , greyhounds are famous as racers . 3089

Siberian Husky Siberia , 1000 ac . The people of northeastern Siberia , used these strong ' working dogs to pull sleds long distances across the snow . I i Pekingese China , AD . 7005 , These lapdogs were bred as pets in ancient China . One Chinese name for a Pekingese means lion ( dog . which refers to the dog long , golden mane . China , 150 ac . Chow ( hows , the working dogs of ancient China , worked as hunters , herders , and guard dogs . Akita lo Japan , 16005 This breed was developed in the cold mountains of , northern Japan as a guard dog and hunting dog . The Akita is ' able to hunt in deep snow and , AD . 7700 is also a powerful swimmer . I This breed has a long , thick coat that protects it . from the cold air of the high plateau . In spite of its small size , the Lhasa guarded homes and temples , Social Studies Activity Draw a timeline that shows the ' approximate date of origin of different I breeds of domestic dogs from 7000 , to the present . Use the information on the map to fill out your ' Include information about where each I breed was developed . 309

Language Arts Picking a Puppy People look for different traits in the dogs they choose . Here is how one expert selected his dog based on good breeding and personality . James . a country veterinarian in Yorkshire , England , had owned several dogs during his lifetime . But he had always wanted a Border terrier . These small , sturdy dogs are descendants of working terrier breeds that lived on the border of England and Scotland . For centuries they were used to hunt foxes , rats , and other small animals . In this story , and his wife , Helen , follow up on an advertisement for Border terrier puppies . James Herriot In several popular books published in the 19705 and , James Herriot wrote warm , humorous stories about the animals he cared for . Border terriers ' She Helen , his wife turned to me and spoke They lived in little barrels which served as kennels agitatedly , I got Mason on the line now . and both of them darted out and stood up at our There only one pup left out of the litter and legs , tails lashing , mouths panting in delight . I felt there are people coming from as far as eighty vastly reassured . With happy , healthy ancestors miles away to see it . have to hurry . What a like those I knew we had every chance of a long time you been out there ! rate dog . We bolted our lunch and Helen , Rosie , As we drove home with the puppy in Emma granddaughter Emma and I drove out to . arms , the warm thought came to me . The wheel Mason led us into the kitchen and pointed to had indeed turned . After nearly fifty years I had a tiny brindle creature twisting and writhing my Border terrier . under the table . Tim him the ' Lang Arts Activity I reached down and lifted the puppy as he curled his body round , apparently trying to James Herriot describes this scene using dialog touch his tag with his now But that my wagged and narrative . The narrative furiously and the pink tongue was busy at my describes Herriot feelings about a memorable hami I knew he was ours before my quick finding the dog he had wanted for so long . Write a narrative . examination for hernia and overshot jaw . The deal was quickly struck and we went outside to inspect the puppy relations . His mother and grandmother were out there . describing a memorable event in your life You might choose a childhood memory or a personal achievement at school . What emotions did you feel ?

How did you make your decision ?

If possible . use dialog in your writing . 310 Math Activity Standard poodle Popular Breeds The popularity of different breeds of dogs changes over time . For example , the line graph shows how the number of poodles registered with the American Kennel Club changed between 1970 and 2000 . Use the table below to create your own line graph for Labrador retrievers and cocker spaniels . Which breed was more popular in 1980 , Labrador retrievers or cocker spaniels ?

How has the number of Labrador retrievers changed from 1970 to 20007 How has the number of cocker spaniels changed over the same time ?

Dog Populations Poodles in the Breed 1970 1930 1990 , Poodle 100000 ' 25667 95 768 172341 ' Retriever ' 21811 75113 105 642 29393 mo Spaniel ' Year Tie It Together Show List your breed characteristics , height , In many places , proud dog owners of all ages weight ' bring their animals to compete in dog shows . the ' 305 behavior . Organize your own dog show . With a partner , choose one specific breed of dog . Pick a breed shown on the map on the weaknesses may develop as a result previous page , or use library resources to ' research another breed . Make a poster for your breed . Include a . Find out what the breed looks like , the time drawing or photo and the Information that and place where it originated , and what traits researched it was first bred for . With your class , organize the dog displays . into categories of breeds , such as hunting dogs , herding dogs , and toy dogs . Find out your breed strengths . Learn what 311